Introduction to Environmental Anthropology | UPSC Important Notes & Study Material

Introduction

Humans have a long history of interacting with their immediate environment
that has resulted in shaping biological as well as cultural evolution to a large
extent.Anthropology as a discipline, specializing in bio-cultural study of humans,
right from its inception has taken keen interest in such interactions. The ancient
Greeko-Roman philosophers as observers of human behaviour and values have
hypothesized that environmental factors like climate and humidity, etc. determine
human culture. Although strict environmental determinism has been rejected,
environmental anthropologists have long focused on how humans adjust and
adapt to their natural environment. Therefore, the question of the degree to which
human action is conditioned by the environment and how human groups might
be classified according to the ways in which they interact with their environment
are some of the on-going anthropological concerns.

As a sub-branch of socio-cultural anthropology, environmental anthropology
concentrates on basic scientific and academic research on the relationship between
people and their environment and how culture mediates in this relationship. It
can be the basis for understanding how past and present human populations
contribute and respond to local and global environmental change. The relationship
between humans and environment through the looking glass of culture can help
understanding the major environmental problems that we confront today and
their possible solutions.

In this Block, assuming that the learner has no prior knowledge of the subject of
Environmental Anthropology, the Unit 1 tries to introduce a basic understanding
of the subject, from introduction to environmental enthropology to its scientific
inquiry, and ends upwith a brief history of its growth and development.The Unit
2 provides an introduction to the basic concepts used in ecology and environmental
anthropology.The Unit 3 describes various environmental pressures which shape
primate behaviour and evaluates different bio-cultural activities adopted as
adaptive strategies by the humans.The Unit 4 discusses about environmental
stress and how these stresses disturb homeostasis. Further, itprovides information
about how the human population with its biological plasticity and cultural

adaptability tries to minimise environmentalstress or increases its strain tolerance.
All the Units in this Block explore key concepts, theories and approaches in the
study of human culture and social activity in relation to ecological systems and
environment. This Block introduces the learners to Environmental Anthropology
and focuses on developing an understanding of natural resources and community
values. Emphasis is placed on cultural, social, economic and political linkages
in natural resource use regimes. The Block also identifies some key areas where
Anthropology can contribute to our understanding of human-environmental
relations.

Introduction to
Environmental
Anthropology
5
History and Development of
Environmental
Anthropology
UNIT 1 HISTORY AND DEVELOPMENT OF
ENVIRONMENTAL
ANTHROPOLOGY
Contents

1.1 Introduction
1.2 Development of Ecological Perspective in Anthropology
1.2.1 Defining Ecological Anthropology
1.2.2 Environmental Determinism versus Cultural Determinism
1.2.3 The Ecosystem Approach, Human Ecology and Processual Human Ecology
1.3 Development of Environmentalism Perspective in Anthropology
1.3.1 Anthropological Engagement with Environmentalism
1.3.2 Emergence and Development of Environmental Anthropology
1.3.3 Definition and Scope of Environmental Anthropology
1.4 Summary
1.5 References
Suggested Reading
Sample Questions
Learning Objectives
By the end of this unit, you will be able to:

• gain understanding of the ecological relationships between humans and the
environment;
• learn the aims and scope of ecological and environmental anthropology;
• know the key authors and theoretical perspectives in environmental anthropology;
• be familiar with the emergence and development of environmental
anthropology; and
• discover how ecological and environmental anthropology is shaping new
ways of thinking about current local, national and global environmental
problems.
1.1 INTRODUCTION
Since its inception, the discipline of Anthropology has broadly dealt with
“environmental” questions, including human perceptions of the natural world
and the relationship between “Nature” and “Culture,” as well as the ways human
populations use culture as an adaptive strategy to cope up with their habitats and
ecosystems. Late in the 19th century and early in the 20th studies of humans and
their environment moved from the “environmental determinism” of the
anthropogeographers, to the “environmental possibilism” of the ethnographers,
and to the “cultural ecology” of Julian Steward (for detail see block 2, unit 1).
More recently, “Environmental Anthropology” has grown as a specialisation
within Anthropology, focusing broadly on the study of environmental issues,
problems, and solutions from an anthropological perspective.Assuming that the

Introduction to
Environmental
Anthropology
learner has no prior knowledge of the subject or Environmental Anthropology,
the unit tries to build an understanding from the ground up introduction to
ecological anthropology, to scientific inquiry, and endswith an overview of growth
and development of Environmental Anthropology.
Ecology is the study of the interaction between living things and their
environment. Human ecology is the study of the relationships and interactions
among humans, their biology, their cultures, and their physical environments.
Before going to know the meaning, definition and scope of Environmental
Anthropology, it is important to first understand what Ecological Anthropology
is historically and philosophically speaking, the roots of Western notions of the
interrelations between man and environment are very old. Since the 1950s
Anthropology has developed approaches to human-environment interactions and
developed the concept Ecological Anthropology. Ecological Anthropology is the
study of how people interact with their social and biophysical environments.

Mostly we try to understand why people behave or think the way that they do. It
represents the link between the sciences of ecology and human culture. The core
ideas – human adaptation, ecosystems, and environmental change – are similar
to those of traditional ecology, but the anthropological notion of culture is added
as an additional level of complexity.

1.2 DEVELOPMENT OF ECOLOGICAL PERSPECTIVE IN ANTHROPOLOGY

Interest in the study between people and the environment around them has a
long history in anthropology. Since the beginnings of the discipline in the 19th
century, scholars have been concerned with the ways in which societies interact
with their environment and utilise natural resources, as with the ways in which
natural processes are conceptualised and classified (Rival, 1998). Much of this
interest centered on the study of subsistence patterns by which populations adapted
to particular biophysical conditions. Precisely for this, according to E. F. Moran
(1996) environmental researchin Anthropology has been a part of the discipline
from its very beginning. It is often referred to as the ecological approach in
Anthropology. Ecological or environmental approach in Anthropology includes
topics as diverse as Primate Ecology, Human Ecology, Ethno-ecology, Historical
Ecology, Political Ecology, Ecofeminism, Environmentalism, Environmental
Justice, Evolutionary ecology, Traditional Ecological Knowledge (TEK),
Conservation, Environmental Risk, Liberation Ecology, and a number of other
areas, many of them interdisciplinary in scope and methodology.

1.2.1 Defining Ecological Anthropology
Ecological Anthropology is broadly concerned with people’s perceptions of and
interactions with their physical and biological surroundings, and the various
linkages between biological, cultural, and linguistic diversity. In Ecological
Anthropology topics to be explored from simple to complex and general to
specific which include subsistence strategies, the ecology of ethnic foodways,
human alteration of the environment, traditional knowledge of wild plants,
ethnobiological classification, natural resource sustainability, intellectual property
rights among indigenous peoples, the Anthropology of tourism, environmental
racism, and conservation policies in both simple and complex societies. It can
involve skills like analyzing tape recordings of conversations to find out what
7
History and Development of Environmental
Anthropology
environmental themes are important to people, following people and recording
their behaviour, or archeology. Ecological anthropology tries to explore the
multilevel ways in which humans adjust to their surrounding by both biological
and socio-cultural processes.
Salzman and Attwood (1996 ) defined Ecological Anthropology is a subfield of
anthropology that deals with complex relationships between humans and their
environment, or between nature and culture, over time and space. It investigates
the ways that a population shapes its environment and may be shaped by it, and
the subsequent manners in which these relations form the population’s social,
economic, and political life. In a general sense Seymour-Smith (1986) describe
show Ecological Anthropology attempts to provide a materialist explanation of
human society and culture as products of adaptation to given environmental
conditions.According to Ellen (1982) Ecological Anthropology applies a systems
approach to the study of the interrelationship between culture and environment.
At the heart of contemporary ecological anthropology is an at the heart of
contemporary ecological anthropology is an “understanding that proceeds from
a notion of the mutualism of person and environment” (Ingold, 1992) and the
reciprocity between nature and culture (Harvey, 1996). As such, ecological
anthropology is itself closely related to human behavioural ecology and
environmental anthropology (Stacy McGrath).
Activity
What is the difference between Ecology and Ecological Anthropology?
1.2.2 Environmental Determinism Vs. Cultural Determinism
There have been several attempts to structure and organize the area of manenvironment
relations in anthropology over roughly hundred from now. In the
era before the turn of the century, when anthropology was evolving as a distinct
discipline, anthropologists and geographers were concerned about the manenvironment
relationships.Development of basic conceptsin ecological
anthropology was not as a smooth accumulation of information and insights, but
as a series of stages.Every stage was a reaction to the previous one rather than
merely an addition to it. “The first stage, is characterised by the work of Julian
Steward and Leslie White, the second is termed neo-functionalism and neoevolutionism,
and the third one is called processual ecological anthropology.The
attempts to address the similarities and differences of Steward and White mark
the second stage of Ecological Anthropology. Boldly oversimplifying, one could
argue that there are two main trends in this second stage: the neoevolutionists,
who claimed that Steward and White were both correct, and the neofunctionalists,
who argued that they were both wrong”. (see Orlove, 1980).
During thue late 19th and early the 20th centuries a number of comprehensive
treatment of environmental thinking in Anthropology and the environment vs
culture controversy have been complied by socio-cultural anthropologists who
have found that an ecological approach is fruitful both in research and teaching.
The framework of these theoretical perspectives reviews has been provided by
some contrasting major schools of thoughts or conceptual approaches, viz,
environmental determinism, environmental possibilsm, functionalism, culturearea
approaches, cultural ecology, racism, evolutionism, historicismand current
approaches in ecological Anthropology including actor-based model, eco-system
based model, ethno-ecology and systems-ecology model etc.

Introduction to Environmental Anthropology

The above conceptual and theoretical perspectives you will learn in detail in the
block 2, unit 1, 2, and 3.In this unit, I will briefly discuss development stages of
basic theoretical Concepts in Ecological Anthropology and history of development
of an environmental perspective in Anthropology.
The concept of cultural evolution and the series of ideas on the relationship
between culture and environment were developed in early Greek view. This idea
was widely accepted throughout the nineteenth century. In the twentieth century
ecological anthropology has proposed, or drawn on, several useful and innovative
theories. Smith, along with Thomas Malthus (1977), developed the ideas of
competition in nature and in human affairs that later fed into contemporary
ecological theories.
Ecological Anthropology was named as such during the 1960s, but it has many
ancestors, including Daryll Forde, Alfred Kroeber, and, especially, Julian Steward.
Columbia University can be identified as the birthplace of Ecological
Anthropology. Early studies of humans and their environment moved from the
“environmental determinism” of the anthropogeographers, to the “Environmental
Possibilism” of the ethnographers, and to the “cultural ecology” of Julian Steward
(Michael A. Little, 2007). The first major theory regarding the interaction between
culture and environment, one that has been in circulation since the time of classical
Greece, is Environmental Determinism (ED), or Environmentalism.In this concept
the idea basically states that environment mechanically “dictates” how a culture
adapts(for detail see block 2, unit 1).For example, the Polynesians must fish and
live in grass huts because they live on tropical islands.
The general orientation of explanations of man-environment interrelations in
the United States shifted towards what came to be called “possibilism”/
environmental possibilism (EP) in the late 1920s and the 1930s. In possibilism,
the environment is seen as a limiting or enabling factor rather than a determining
factor. Possibilism is really an interactive process between culture and the
environment.Daryll Forde, Boas, Wissler and Kroeber are the believers of this
thought (for detail see block 2, unit 1)The common features of the above themes
ED and EP are that they conceptualised the interaction between the human and
their environment as mainly unidirectional, rather than systematic. They
emphasised stages rather than the process.

During the 1920s-30s the time was ripe for a reassessment of the prevalent views
on the relation between man, culture, and environment; as well as the evolution
of cultures. The inadequacy in explaining cultural diversity, however, remained
an issue and in a search for a more precise understanding of the effect of the
environment on cultures Steward (1955) developed a methodology called Cultural
Ecology.Due to contact with noted geographer Carl Sauer, Steward’s work in
cultural ecology led him to examine the effect of environment on culture. In the
1950s-60s significant progress came from the development of what came to be
known as “Cultural Ecology,” engaged with the analysis of cultural adaptation
to natural environments.He conducted pioneering field research on the interaction
of a particular human society and its natural environment in the Western United
States working with Shoshone, Paiute, and other Native Americans. He moved
cultural ecology a step forward by rejecting the “fruitless assumption that culture
comes from culture” (Steward, 1955). Steward searched for the adaptive responses
of various cultures to similar environments (Orlove, 1980). He examined the
9
History and Development of Environmental
Anthropology

available resources and distribution in relation to the technology, economic
arrangements, social organisation and demography of a certain place. As a result,
he identified a ‘culture core’ consisting of the elements of a culture influenced
by the environment, i.e. the features most closely related to subsistence activities
and economic arrangements. Yet, cultural ecology could neither provide a model
for explaining the origin and persistence of cultural features, nor for determining
the extent of environmental influence in the evolution of specific cultures (Netting
1977; Orlove, 1980).
As a reaction, in the 1960s and 1970s new schools of thought were formed based
on cultural determinism, i.e. the idea that culture influences the environment.
One of those schools, ethno-ecology, describes the conceptual models that people
have of their environment (see details in the block 2, unit 3). Researchers like
Brent Berlin, Harold Conklin, Charles Frake, and others pioneered the
development of ethno-ecology. It distinguished, for example, ‘folk nature’ or the
perceptions that people have on nature, from ‘real nature’ on which these
perceptions are based. The approach used classifications and shared its methods
and underlying premises with cognitive Anthropology. In the end, however, neither
environmental nor cultural determinism formed a satisfactory basis to describe
human-environment relationships. Alternatively, instead of shaping or being
shaped by environmental factors, human beings were understood to interact with
their environments in mutually constructive ways (Milton, 1996).

1.2.3 The Ecosystem Approach, Human Ecology and Processual
Human Ecology
Other approaches followed Cultural Ecology that expanded the scope of
environmental research inAnthropology. In the 1960s and 1970s, the field became
influenced by new concepts developed by anthropologists who largely structured
their data based on ecological models. Roy A. Rappaport, and Andrew P. Vayda
(1968), developed an ecosystem approach that treated human populations as one
of a number of interacting species and physical components and transformed
Cultural Ecology into Ecological Anthropology.While Steward tied culture with
the environment, a new approach, called the “new ecology,” tied culture with the
emerging science of systems ecology (e.g.,Vayda and Rappaport, 1968). The
ecosystem approach, brought into play by anthropologists like Rappaport (1968)
and Vayda (1969), conceptualised human populations as participants in
ecosystems. It was a first attempt to reconcile ecological sciences with
functionalismin Anthropology. Research focused, amongst others, on the material
outcomes of economic activities and the efficiency of subsistence systems.
Yet,
the approach was limited with its focus on ‘units’ and ‘populations’ rather than
cultures and its preference for small-scale (Island) societies (Rappaport,
1969).They suggested that instead of studying how cultures are adapted to the
environment, attention should be focused on the relationship of specific human
population to specific ecosystem. In their view, human beings constitute simply
another population among the many populations of plants and animals species
that interact with each other with the non-living components (climate, soil, water
etc) of their local ecosystem. Thus, the ecosystem rather that culture, constitutes
the fundamental unit of analysis in their conceptual framework for human ecology.
The analytic unit shifted from “culture” to the ecological population, which was
seen as using culture as a means (the primary means) of adaptation to
environments. It was argued that human cultures were not unique but formed
10
Introduction to

Environmental Anthropology
only one of the population units interacting “to form food webs, biotic
communities, and ecosystems” (Vayda and Rappaport, 1968). A broader focus
was presented by Human Ecology which was concerned with the ways human
populations interact with their environment. Yet, even though it acknowledged
the importance of knowledge, information, and people’s understanding of the
world (Ellen, 1982), the ecosystem approach excluded the unobservable
components of culture.
In the mid 1970s, in contrast to Cultural Ecology, neo-evolutionism and
neofunctionalism, another approach emerged: Processual Ecological
Anthropology. The use of the term “process” refers to the importance of diachronic
studies in Ecological Anthropology and to the need to examine mechanisms of
change. However, the term “ProcessualEcological Anthropology” signifying
current developments in the field does appear to be new. It focused on the
processual relationship between the local population and their immediate
environment conditioned by the intervention of external political, legal, and
economic factors. Important research trends were, amongst others, the relation
between demographic variables and production systems, the response of
populations to environmental stress, and the formation and consolidation of
adaptive strategies (Orlove, 1980). ProcessualEcological Anthropology examined
shifts and changes in individual and group activities and focused on the
mechanisms by which behaviour and external constraints influenced each other.
It stimulated the importance of decision-making models in Ecological
Anthropology.

Two additional theoretical and methodological frameworks were developed
mainly in the 1980s and 1990s to try to render Ecological Anthropology more
scientific. The Neomaterialist, Marvin Harris, developed the approach of Cultural
Materialism. It is a practical, rather straightforward, functionalist approach to
Anthropology with a focus on the specific hows and whys of culture.Marvin
Harris vigorously pursued explicitly and systematically the development of
cultural materialism as a research strategy to reveal and explain the ecological
rationale underlying various aspects of culture. He divided the cultural system
into three components infrastructure,structure, and superstructure. Harris argued
that the infrastructure is most basic and most influential because it functions as
the ultimate adaptive mechanism for the very survival and maintenance of
individuals and society as a whole (see details in the block 2, unit 2).

Human behavioural or evolutionary ecology is the second innovative framework
pioneered by Eric Alden Smith and Bruce Winterhalder. It shifts attention to
individuals as the locus of adaptation with an emphasis on decision making in
the use of natural resources ranked according to their relative costs and benefits
(optimal foraging theory). This connects human ecology more directly with natural
selection and other evolutionary theories. Both of these special frameworks,
cultural materialism and human behavioural ecology, have been criticized as
simplistic and reductionistic. Nevertheless, both have proven to have some validity
and utility in advancing the anthropological understanding of human-environment
interactions.

In the following years, anthropologist who had borrowed analytic concepts from
other disciplines used them to critique then-prevailing understandings of humanenvironment
relations, including the view that indigenous landuse systems were
11
History and Development of Environmental Anthropology.

inferior to modern scientific models. Numerous research experiences by
ecological anthropologists demonstrated the intimate associations between local
communities and their environments and the extensive knowledge generated
through these associations. The insights acquired into such resource use systems
contributed to undermining orthodoxy in natural sciences. Of particular
importance was that they showed that these systems were not always destructive
for the environment. This was critical for the late-modern move away from a
dichotomised conception of nature and culture (Dove, 2001).

Previous research had been largely synchronic, examining a particular society as
if it wereisolated, traditional, static, and timeless, and also as if the society had
no lasting cumulative impact on its environment and the latter was static as well.
Ecological anthropology diversified further in 1990s by adding research variously
focused on historical, political, or spiritual aspects of human ecology and
adaptation. William Balee, John Bennett, and Carole Crumley, among others,
developed a diachronic approach to examining the interactions between the
sociocultural and environmental systems over extended periods of time as they
transformed one another within a regional landscape. Since the 1990s substantial
diversification of approaches within ecological anthropology involves a growing
emphasis on applied rather than basic research, although certainly the two are
often interdependent. However, with the worsening ecocrisis and other factors,
increasingly research has concentrated on identifying and solving practical
environmental questions, problems, and issues. This is the arena of environmental
anthropology per se. Researchers in this arena still pursue various approaches
within Ecological Anthropology to investigate matters of survival, adaptation,
and change with an emphasis on culture, communities, and fieldwork.

Activity
Explain how analytic unit shifted from culture to the ecological population?
1.3 DEVELOPMENT OF ENVIRONMENTALISM
PERSPECTIVE IN ANTHROPOLOGY
Anthropology traditionally has strong links to the study of the environment
through its focus on human interaction in environmental context. This basic
connection is depicted by Milton, who says: ‘If one accepts the anthropological
cliche´ that culture is the mechanism through which human beings interact with
(or, more controversially, adapt to) their environment (Ingold, 1992), then the
whole field of cultural anthropology can be characterised as human ecology’.
Since the 1980s, anthropological research on environmental issues has been part
of a broad public sphere that has witnessed a sharp increase in environmental
concerns and activism throughout the world. That has, in turn, been accompanied
by significant interrelational changes between humans and their environment,
resulting from the use of new communication and biological technologies.
Given
the breadth and complexity of environmental issues, academic disciplinary
boundaries are easily crossed and new sites of transdisciplinary research have
emerged that combine natural and social-scientific approaches in unique ways.
Anthropology, however, has specific contributions to make to the wider
environmental research field (Paul Little, 1999).
12
Introduction to
Environmental
Anthropology

1.3.1 Anthropological Engagement with Environmentalism
In common usage, the term environment is often used as a synonym for Nature
(i.e. the biophysical or nonhuman environment), but this usage creates great
conceptual confusion because the environment of a particular human group
includes both cultural and biophysical elements. By extension, the organism/
environment dynamic, which is relational and perspectivist, is often incorrectly
fused with the nature/cultured dualism, which is essentialist and substantive.
The concept of environment as a research tool allows for the delimitation of a
wide range of socio-natural units of analysis that transect the nature/culture
division orthogonally (see Paul Little, 1999).

In this context, Paul Little and other anthropologists preferthe term
environmentalism to an explicit, active concern with the relationship between
human groups and their respective environments. Although “environmentalist”
usually refersto political activists, the termcan reasonablyinclude persons and
groups that are directly involved with understandingand/or mediating
thisrelationship. Thus, anthropologists and other social scientistswho are involved
in environmental research can be considered as representingthe environmental
wing of their respective disciplines.

Current environmental research in Anthropology falls into two major areas that
have distinct methodologies and objects of study. The first, called Ecological
Anthropology, uses ecological methodologies to study the interrelations between
human groups and their environment. The second, called Environmental
Anthropology involve policy and value orientation, application,analytic unit,
scale, and method to study environmentalism as a type of human action.
The sub field Environmental Anthropology holisticallyunderstands the importance
of cultural perceptions when dealing with environmental issues. There are number
of anthropologists who are concerned to engage with the discourse of
environmentalism. Initially, let us consider Brosius’ (1999) statement that
environmentalism refers broadly to the field of ‘discursive constructions of nature
and human agency’. He makes the point that the study of environmentalism
should encompass much more than an analysis of the different social movements
involved and their various trajectories over time and space. As stated above, he
feels that at the crux of environmentalism is the ongoing discourse about human
beings and their place within nature. As a postmodernist thinker and an
anthropologist, Brosius declares that the relevance of Anthropology in this field
of investigation is due to its unique concentration upon the phenomenon of culture.
He urges anthropologists to see environmentalism as a ‘rich site of cultural
production’ (ibid:277) and stresses that ‘a whole new discursive regime is
emerging and giving shape to the relationships between and among natures,
nations, movements, individuals, and institutions’ (ibid).

Similarly, Milton depictsenvironmentalism as a trans-cultural discourse that, not
being rooted in any specific culture, spans the local through to the global and
now has become a specific cultural discourse existing within, although not
bounded by, other cultural systems. Thus, environmentalism is perceived by her
to transcend many traditional geographical and conceptual boundaries such as
east/west, north/south, first world/third world and left/right. As Milton describes
it, environmentalism incorporates ‘all culturally defined environmental
13
History and Development of
Environmental
Anthropology

responsibilities, whether they are innovative or conventional, radical or
conservative’.Obviously, these responsibilities vary between cultural settings but,
as Milton observes, they originate from the recognition that environmental
problems are caused by human interaction with the environment. She feels that
the key to a viable future lies in a better understanding of human activity (ibid:11).
Furthermore, in her view environ-mental discourse does not merely articulate
perceptions of the environment, it contributes to their formulation. In this way,
the whole spectrum of thought is included in Milton’s analysis because a proenvironmentalist
stance is not required for discourse to be considered

environmental (ibid:8). If we also take into account Brosius’ description of
environmentalism provided earlier, we see that anthropologists have begun to
discern environmentalism as being expressed through a myriad of social and
cultural relationships and situations. Milton explains this well when she writes:
“In this framework, social movements and political ideologies become specific
cultural forms through which environmental responsibilities might be expressed
and communicated. Instead of environmentalism being seen as a category of
social movement or ideology, these forms of cultural expression become types
of environmentalism”. (ibid: 8).

Many environmental problems that have emerged from the multiplicity of
interrelations between humans and their environments have been accompanied
by a concomitant surge in environmentalisms, each with their respective
environmentalists. The ethnographic analysis of and political involvement in
these many environmentalisms on the part of anthropologists and other social
scientists have generated, during the past two decades, a field of study in its own
right.

In recent past there has been much discussion about the relevance of the discipline
of Anthropology to the various emergent discourses on the environment. Kay
Milton has made a number of important contributions to this area of
anthropological investigation over recent years. In 1993 she edited a work, entitled
Environmentalism: The View from Anthropology, which attempted to position
anthropology more centrally with in the multi-disciplinary study of
environmentalism (see Milton, 1993).Eeva Berglund is another anthropologist
who wishes to establish Anthropology as a legitimate participant in the study of
environmentalism. In her book, Knowing Nature, Knowing Science:
An
Ethnography of Environmental Activism, she explores the role of what she terms
‘techno-science’ in environmental discourse (see Berglund, 1998).
Brosius in his article in Current Anthropology (1999) provides an overview of
the engagement by anthropologists in the field of environmentalism, which
includes aspects of the past, present and future. He says the recent trend toward
anthropological engagement with environmentalism was not at all inevitable.

Rather, it is the result of a series of particular historical contingencies, both
practical and theoretical. He addressed this by noting significant differences
between ‘the Ecological Anthropology of the 1960s and early 1970s and what
some are calling the ‘‘Environmental Anthropology’’ of the present. Drawing its
insights primarily from the field of ecology, the former is characterised by a
persistent interest in localised adaptations to specific ecosystems and by an abiding
scientism: to the extent that cultural or ideational factors enter into analyses of
this sort, they are viewed primarily with respect to their adaptive significance.
14
Introduction to
Environmental
Anthropology

The latter draws its insights from a range of sources: poststructuralist social and
cultural theory, political economy, and recent explorations of transnationalism
and globalisation, among others.
Brosius’ (1999: 278) assertion that environmentalism refers broadly to the field
of ‘discursive constructions of nature and human agency’. He makes the point
that the study of environmentalism should encompass much more than an analysis
of the different social movements involved and their various trajectories over
time and space. As stated above, he feels that at the crux of environmentalism is
the ongoing discourse about human beings and their place within nature. As a
postmodernist thinker and an anthropologist, Brosius declares that the relevance
of Anthropology in this field of investigation is due to its unique concentration
upon the phenomenon of culture. He urges anthropologists to see
environmentalism as a ‘rich site of cultural production’ (ibid: 277) and stresses
that ‘a whole new discursive regime is emerging and giving shape to the
relationships between and among natures, nations, movements, individuals, and
institutions’ (ibid).

In assessing what lies behind the rather striking growth in interest in
environmentalism among anthropologists,Brosiuscites three factors. The first is
simplythe more general trajectory of growth in environmentalscholarship across
a wide range of disciplines, a processwhich accelerated in the late 1980s. Indeed,
the past decadehas witnessed a remarkable florescence in environmental scholarship
and the emergence or growth ofa host of new subdisciplines: environmental
history, environmental ethics, environmental economics, environmentallaw,
environmental security, and politicalecology, to name just a few. To the extent
that anthropologistshave developed an interest in environmentalism,then, we
are participating in a larger, transdisciplinaryprocess. One of the things that makes
thecurrent moment so promising is the degree to whichscholars from a range of
disciplines—geography, politicalscience, history, legal studies, science and
technologystudies, media studies, and others—are engaged inprojects that
converge on an interest in environmentalism.

This a period with great potential for buildingrich transdisciplinaryintersections,
and many anthropologistsappear to be doing that. One might go so faras to claim
that, in the study of environmentalism atleast, the boundaries between disciplines
are eroding toa degree not seen before.

A second factor leading to the present anthropological interest in environmentalism
is the simple fact that so many of us have witnessed the emergence (or arrival) of
environmental movements at our field sites. According to Brosius, Fisher and
Turner environmental NGOs have become highly visible players in the terrain
that we once thought we could claim as our own—the rural/remote community.
As this has occurred, we have seen local communities mobilise or adopt elements
of transnational environmental discourse in ways we had not witnessed before
(see Brosius, 1999).

A third element that has engendered an interest in environmentalism among
anthropologists has been a series of recent theoretical trends both within our
discipline and beyond. This is a rather complicated scenario, with a considerable
degree of overlap between various areas of theoretical and empirical focus. Most
notable, perhaps, has been the trend since the mid-1980s toward what Marcus
15
History and Development of
Environmental
Anthropology
and Fischer refer to as ‘‘the repatriation of anthropology as cultural critique’’
(1986). Uncomfortable with the way we see otherness essentialised in indigenous
rights campaigns, acculturative processes elided in an effort to stress the
authenticity of indigenous peoples, and concepts such as ‘‘wilderness’’ deployed
in environmentalist campaigns, we have taken it as our task to provide critical
commentary (see Brosius, 1999).

The study of social movements with environmental concerns has expanded the
notion of environmentalism in Anthropology to include not only explicitly
environmentalist nongovernmental organisations (NGOs) in the northern
hemisphere, but also a large number of movements in the industrializing nations
of poor or marginalised peoples that are struggling with such environmentally
based issues as control over and access to natural resources, encroachment on
their lands and livelihood, and protests against environmentally destructive
development projects. Martinez-Alier developed the concept of the
environmentalism of the poor and it has been applied to India by Guha, who
mentions situations that have “pitted rich against poor: logging companies against
hill villagers, dam builders against forest tribals, multinational corporations
deploying trawlers against artisanal fisherfolk rowing country-boats (see Paul
Little, 1999).

In the meantime, women’s environmental movements tend to arise when gender
is a determining factor in issues involving the division of labor, access to natural
resources, and property relations in ways that are disadvantageous to women
(Carney, 1996). In efforts to maintain existing rights or to resist new policies that
seek to extinguish them, the emergence of women’s resistance movements that
are directly related to environmental issues has generated the new fields of feminist
political ecology and ecofeminism.The ways in which these insights have been
refracted into other concerns is an important part of the Anthropology engagement
with environmentalism (see Paul Little, 1999).

According to Miller (1993) the complex domain of environmental rights refers
to those cases where the claims and rights of peoples to territories, natural
resources, knowledge systems, and even their bodies are being ignored or abused.
The rights of “indigenous or tribal peoplesto the lands and natural resources they
have historically occupied and continue to use have been a central focus of
anthropologists working with these groups. Anthropological research on various
environmental rights issues has been ethnographically well documented by
anthropologists.Studies of other environmental issues like biodiversity
conservation, displacement, ecodevelopment, and planning are explored by
anthropologists within the framework of the concept of resident peoples, which
defines highly diverse societies in relation to their presence in protected areas
that are taken for granted as an existing good.Importance in contributing
anthropologists’ interest in environmentalism has been the work of a series of
writers interested in critical examinations of contemporary discourses of
development. Anthropologists interventions and efforts to understand the
phenomenon of globalisation and the forms of articulation between ‘‘the local’’
and globalizing processes of environmentalism have also been of significance in
the field of Environmental Anthropology(see Paul Little, 1999).
Activity
What is environmentalism according to anthropologists?
16
Introduction to
Environmental
Anthropology
1.3.2 Emergence and Development of Environmental
Anthropology
Although the discipline of Anthropology has its origin in the study of smallscale
societies, anthropologists began to consider human entities and their
environments as located in complex social processes. Greater appreciation of
the complexity of social and ecological systems developed alongside a growing
interest in interpreting the dynamics of ecological systems in terms of the dynamics
of larger political systems. Beyond the study of subsistence communities, scholars
enlarged their frame of reference to encompass global structures and situated the
cultures they studied within the broader international political economy. The
changes in Ecological Anthropology reflect a more general shift in anthropological
research drawing attention towards the intersection of global, national, regional
and local systems. New approaches emerged mainly in the 1990s concerned
with the impact of markets, social inequalities, and political conflicts to analyse
forms of social and cultural disintegration associated with the incorporation of
local communities into a modern world system (Paulson et al., 2005). It became
a challenge for anthropology to study local environmental and social changes
associated with global trends. Thereby, anthropologists have shown an extensive
interest in questions of nationalism and identity, of focusing on the hybrid
relationships between local integration and global politics, places-in-between,
and on what has come to be termed modernity (Lovell, 1999). While looking at
the mutual processes of definition and appropriation that take place between
what has been termed local and global settings, conceptual, spatial, and cultural
scales expanded in academic discourse.
A major difficulty in analysing the complexity of human-nature relationship is
that no single social theory of environmental phenomena in human experience
has been developed, just as there is a lack of methods and basic categories to
study them (Arizpe et al., 1996). Finding an appropriate methodology to shed
light on amalgamations between nature and culture is the prime challenge in
cross-cultural investigation. The understanding of how nature is constructed and
resource management is conceived in different cultural settings is not an easy
task, for the questions raised and the answers sought lie along the margins of
several disciplines. Referring to recent theoretical trends, Brosius writes of a
rather complicated scenario that is informed by a considerable degree of overlap
between various areas of theoretical and empirical focus (1999). To address both
the dynamics of culture and natural resources requires not only transcending
disciplinary lines but also that natural and social sciences be brought together.
The result, it has been suggested by Nakashima (1998), may be compared to a
labyrinth through which one must navigate with caution. This challenge has
been taken up by a number of anthropologists with different scopes and research
traditions. Out of the multi-layered engagement an environmental anthropology
emerged (see Townsend, 2000; Haenn and Wilk, 2006). While the Ecological
Anthropology of the 1960s and 1970s was characterised by an interest in localised
adaptations to specific ecosystems and by an ethnoscientific gaze, contemporary
environmental anthropology is more attentive to issues of power and inequality,
the contingency of cultural and historical formations, the significance of regimes
of knowledge production, and the acceleration of translocal processes (Brosius,
1999).The primary approaches within contemporary Ecological Anthropology
are cultural ecology, historical ecology, political ecology, and spiritual ecology.
Environmental anthropology builds on the above past experience of
17
History and Development of
Environmental
Anthropology
anthropologists work. Environmental anthropology blends theory and analysis
with political awareness and policy concerns. Accordingly, new subfields have
emerged, such as applied ecological anthropology and political ecology
(Greenberg and Park, 1994).
As it is threaded through all subfields of the discipline, environmental
anthropology combines a multitude of prevailing perspectives and conceptual
approaches in multi-sited contexts. Focusing on the interactions of local and
global patterns of resource management, a growing body of contributions has
appeared examining the dynamic linkages of human societies with their natural
environments. The implication of pluralist genres of research involves a wide
range of orientations in the emergence of new disciplinary factions. The scale
ranges from site-specific studies focused on local economies to perspectives
aimed at questions of global scope. At the same time, accounts on
environmentalism itself (Argyrou, 2005) and environmental bureaucracies and
agencies (Little, 1995) appeared as objects of recent study.
Environmental Anthropology, as you will learn, is a general term that can be
applied to many ways of studying humans as integral components of the
environment. Environmental Anthropology may be viewed as the study of applied
action and/or advocacy research to address practical environmental questions,
problems, and concerns. Often, new policy is the outcome of such applied action
or research. In most cases, such study centers upon the dynamic interaction
between human beings and their ecosystems or natural environments. Although
Environmental Anthropology only emerged in the 1980s, it has flourished since
the 1990s.
1.3.3 Definition and Scope of Environmental Anthropology
Environmental Anthropology is a more recent outgrowth of Ecological
Anthropology, which can be characterised as the study of the interrelationship
between human groups, cultures, and societies and the ecosystems in which they
are embedded in all times and all places across planet earth. Scholars have
delineated Environmental Anthropology as becoming more prominent in the
1980s and typically focusing on analysis and application of anthropological
knowledge to contemporary environmental issues. Ecological and Environmental
anthropology can most productively be viewed as a single interrelated discipline,
with Ecological Anthropology focusing more on basic academic research and
Environmental Anthropology being more focused on contemporary environmental
issues and having more of an applied, practicing, critical, and/or advocacy
approach.
According to Peter Brosius (1999) Environmental Anthropology provides a broad
disciplinary framework.He describes Environmental Anthropology as
investigating discourse, power, knowledge, resistance, development, cultural
studies, and political ecology through transdisciplinary work, and he identifies
three major current trends: a critique of essentialised images, an emphasis on
contestation and consideration of stakeholders, and an interest in globalisation.
Environment anthropology studies the way communities and social groups
identify and solve environmental problems by examining culturally diverse
perceptions, values and behaviours. Environmental anthropology contributes to
policy formulation and planning by improving and facilitating the communication
18
Introduction to
Environmental
Anthropology
process among diverse stakeholder groups. Environmental Anthropology helps
bridge the gaps between scientists, resource managers and resource users and
the public (Society for Applied Anthropology, 2002).
Kottak (1999) describe Environmental Anthropology is a new approach linking
global to local systems, blends theoretical and applied research, focuses on
political aspects, and recognizes culture as mediating in ecological processes
rather than as merely an adaptive tool.In Environmental Anthropology, everything
is on a larger scale. The focus is no longer mainly the local ecosystem. The
“outsiders” who impinge on local and regional ecosystems become key players
in the analysis, as contact with external agents and agencies (for example,
migrants, refugees, warriors, tourists, developers) has become commonplace.
Concerned with proposing and evaluating policy, Environmental Anthropology
attempts not only to understand but also to devise culturally informed and
appropriate solutions to such problems and issues as environmental degradation,
environmental racism, and the role of the media, NGOs, and various kinds of
hazards in triggering ecological awareness, action, and sustainability.
Environmental anthropologists focus on new units of analysis—national and
international, in addition to the local and regional, as these levels vary and link
in time and space. Entering into a dialogue with schools of natural resources and
the environment, anthropology’s comparative perspective adds an international
dimension to the understanding of issues like environmental justice and
ecosystems management, which natural resource specialists have been studying
for decades.
Environmental Anthropology increasingly contributing research of broader
relevance to the local, national, international, and global communities in coping
with natural resources, hazards, and other environmental problems and issues.
In various ways anthropologists have addressed pivotal environmental issues
including the population explosion, natural resource depletion such as soil erosion,
unsustainable economic development and consumption levels, habitat destruction
like deforestation, biodiversity loss, environmental mismanagement, pollution,
hazards, environmental problems, conflict zones, climate change and
environmental justice. Environmental anthropology have developed the
foundation, maturity, momentum, and achievements to continue to contribute to
our understanding and advancement of human ecology and adaptation from the
local to the global levels as long as humanity has a future.
Increasing interest in environmentalism in recent years has shaped anthropology’s
role in analyzing these efforts. Brosius (1999) believes the goal is not simply to
understand human impact on the environment, but also to investigate how the
environment is constructed, represented, and contested, recognizing the power
of discourse in creating reality, especially in the perpetuation of structures of
domination. He discusses the recent growth of environmental NGOs, national
agencies, and transnational institutions concerned with the environment as well
as the resulting theoretical trends in Anthropology that critique environmental
movements, rhetoric, and representations of indigenous people. He also describes
eco-politics, community-based conservation, and environmental racism as other
current topics of interest in environmental anthropology.
As Thin (1996) writes, Environmental Anthropology enhances the understanding
not only of natural resources, human needs and uses of those resources, but also
19
History and Development of
Environmental
Anthropology
of the spatial arrangements by which resources are appropriated and managed.
Cross-cultural comparison based on evidence from long-term studies of such
locally adapted arrangements may promote better global understanding of the
conditions under which resource management remains sustainable or else results
in deterioration. Multidisciplinary research teams incorporating high tech
resources such as geographical information systems, remote sensing, and satellite
data imaging etc.
Activity
What is environmental anthropology and how did it emerge?
1.4 SUMMARY
Anthropology has a long history of exploring many facets of human-environment
interaction. Since the beginnings of the discipline in the 19th century and early
in the 20th century, scholars have been concerned with the ways in which societies
interact with their environment and utilise natural resources, as with the ways in
which natural processes are conceptualised and classified. Since, the 1950s and
60s Anthropology has developed approaches to human-environment interactions
in Ecological Anthropology. Ecological Anthropology is the study of how people
interact with their social and biophysical environments.
Ecological Anthropology was named as such during the 1960s, but it has many
ancestors, including Daryll Forde, Alfred Kroeber, and, especially, Julian Steward.
Columbia University can be identified as the birthplace of Ecological
Anthropology. Early studies of humans and their environment moved from the
“Environmental Determinism” of the anthropogeographers, to the “environmental
possibilism” of the ethnographers, and to the “Cultural Ecology” of Julian Steward
(Michael A. Little, 2009). Steward’s cultural ecology influenced the ecological
anthropology of Roy Rappaport and Andrew P.Vayda, but the analytic unit shifted
from “culture” to the ecological population, which was seen as using culture as
a means (the primary means) of adaptation to environments.
The Ecological Anthropology of the 1960s and 70swas known for its
functionalism, and systems theory.The studies in the in Ecological Anthropology
pointed out that natives did a reasonable job of managing their resources and
preserving their ecosystems but those studies, relying on the norm of cultural
relativism, generally aimed at being value-neutral. Anthropologists examined
the role of cultural practices and beliefs in enabling human populations to optimize
their adaptations to their environments and in maintaining undegraded local and
regional ecosystems.
By contrast, the new ecological, or environmental, Anthropology blends theory
and analysis with political awareness and policy concerns. Accordingly, new
subfields have emerged, such as applied Ecological Anthropology and Political
ecology (Greenberg and Park,1994).
Environmental Anthropology is a more recent outgrowth of Ecological
Anthropology, which can be characterised as the study of the interrelationship
between human groups, cultures, and societies and the ecosystems in which they
are embedded in all times and all places across planet earth. Scholars have
20
Introduction to
Environmental
Anthropology
delineated Environmental Anthropology as becoming more prominent in the
1980s and typically focusing on analysis and application of anthropological
knowledge to contemporary environmental issues. Ecological and Environmental
Anthropology can most productively be viewed as a single interrelated discipline,
with Ecological Anthropology focusing more on basic academic research and
Environmental Anthropology being more focused on contemporary environmental
issues, problems and having more of an applied, practicing, critical, and/or
advocacy approach.
Environmental Anthropology increasingly contributing research of broader
relevance to the local, national, international, and global communities in coping
with natural resources, hazards, and other environmental problems and issues.
In various ways anthropologists have addressed pivotal environmental issues
including the population explosion, natural resource depletion such as soil erosion,
unsustainable economic development and consumption levels, habitat destruction
like deforestation, biodiversity loss, environmental mismanagement, pollution,
hazards, environmental problems, conflict zones, and climate change.
Environmental Anthropology have developed the foundation, maturity,
momentum, and achievements to continue to contribute to our understanding
and advancement of human ecology and adaptation from the local to the global
levels as long as humanity has a future.
1.5 REFERENCES
Argyrou, Vassos. 2005.The Logic of Environmentalism. Anthropology, Ecology
and Postcoloniality. New York [u.a.]: Berghahn Books (Studies in Environmental
Anthropology and Ethnobiology, 1).
Arizpe L., Fernanda P., Margarita V. 1996.Culture and Global Change: Social
Perceptions of Deforestation in the Lacandona Rain Forest in Mexico. Ann Arbor:
University of Michigan Press.
Berlin, B. 1992.Etbnobiological Classification.Princeton: Princeton University
Press.
Berglund, E. 1998.Knowing Nature, knowing science: An Ethnography of
environmental activism. Cambridge, UK:White Horse Press.
Brosius, Peter J. 1999.Analyses and Interventions: Anthropological Engagements
with Environmentalism. Current Anthropology40 (3), 277-309.
Dove, M. 2001.Interdisciplinary Borrowing in Environmental Anthropology and
the Critique of Modern Science. In: C. L. Crumley (ed.), New Directions in
Anthropology and Environment. Intersections, 90-110. Walnut Creek: Altamira
Press.
Ellen, R. 1982.Environment, Subsistence and System: The Ecology of Smallscale
Social Formations. Cambridge University Press, Cambridge.
Greenberg, James B., and Thomas K. Park. 1994.Political Ecology. Political
Ecology 1:1-12.
21
History and Development of
Environmental
Anthropology
Haenn, Nora & Richard Wilk (eds.) 2006.The Environment in Anthropology: A
Reader in Ecology, Culture, and Sustainable Living. New York [u.a.]: New York
University Press.
Harney, Dawid. 1996 Justice, Nature and the Geography of Difference. London
Blackwell.
Ingold, T.1992.Culture and the perception of the environment.In: E.Croll&
D.Parkin (Eds), Bush base: Forest farm: Culture, environment and development.
London: Routledge.
Kottak, Conrad P. 1999.“The New Ecological Anthropology.”American
Anthropologist, 101(1): 23-35.
Little, P.E. 1999.Environments and Environmentalisms in Anthropological
Research: Facing a New Millennium. Annual Review of Anthropology.28:253-
284.
Lovell, Nadia 1999.Introduction. Belonging in Need of Emplacement? In N.
Lovell (ed.), Locality and Belonging, 1-24. London [u.a]: Routledge.
Milton, K., ed. 1993.Environmentalism: The view from anthropology. London:
Routledge.
Milton, K. 1996.Environmentalism and Cultural Theory: Exploring the Role of
Anthropology in Environmental Discourse. Routledge, London/New York.
Moran, E. F. 1979.Human Adaptability.North Scituate, Mass: Duxbury Press.
Moran, E. F. 1996.Environmental Anthropology: In Encyclopedia of Cultural
Anthropology Vol. 2. D. Levinsion, M. Ember (eds.). Henry Holt and company,
New York.
Nakashima, Douglas. 1998.Conceptualizing Nature. The Cultural Context of
ResourceManagement.Nature & Resources.34 (2), 8-22.
Netting, R. McC. 1977.Cultural Ecology.Cummings Publishing Company,
Reading, Massachusetts.
Orlove, Benjamin S. 1980.Ecological Anthropology, Annual Review of
Anthropology Vol 9: 235-273.
Paulson, S., Lisa L. Gezon., Michael Watts. 2005.Politics, Ecologies,
Genealogies. In : S. Paulson & L. Gezon (eds.), Political Ecology Across Spaces,
Scales, and Social Groups, 17-37. New Brunswick [u.a.]: Rutgers University
Press.
Rappaport, R.A. 1968.Pigs for the Ancestors: Ritual in the Ecology of a New
Guinea People. Yale University Press, New haven.
Rappaport, R.A. 1969.Some Suggestions Concerning Concept and Method in
Ecological Anthropology. In: D. Damas, Ed. Contributions to Anthropology:
Ecological Essays. National Museum of Canada, Bulletin 230. Queens Printers
for Canada, Ottawa.
22
Introduction to
Environmental
Anthropology
Rival, Laura (ed.) 1998.The Social Life of Trees.Anthropological Perspectives
on Tree Symbolism. Oxford: Berg.
Salzman, Phillip Carl and Donald W. Attwood.1996.Ecological Anthropology
In Encyclopedia of Social and Cultural Anthropology. Alan Barnard and Jonathan
Spencer, eds. Pp. 169-172. London: Routledge.
Smith, Thomas. 1977.Nakahara: Family Farming and Population in a Japanese
Village, 1717–1830, Stanford, CA: Stanford University Press.
Society for Applied Anthropology. 2003. Retrieved May 3, 2002 from: http://
www.sfaa.net/eap/ea.html.
Steward, J. 1955.“The Concept and Method of Cultural Ecology.” In Theory of
Culture Change: The Methodology of Multilinear Evolution, Urbana: University
of Illinois Press.
Thin, Neil.1996.Environment In: A. Barnard & J. Spencer (eds.), Encyclopedia
of Social and Cultural Anthropology, 185-188. London [u.a.]: Routledge.
Townsend, Patricia K. 2000.Environmental Anthropology:From Pigs to Policies.
Prospect Heights: Waveland Press.
Vayda, Andrew P., and Roy A. Rappaport.1968.Ecology, Cultural and
Noncultural. In: Introduction to Cultural Anthropology: Essays in the Scope and
Methods of the Science of Man. James A. Clifton, ed., pp. 477–497. Boston:
Houghton Mifflin.
Vayda, A.P., Ed. 1969.Environment and Cultural Behaviour. The Natural History
Press, New York.
Suggested Reading
Peace, A. 1996. Loggers are environmentalists too: towards an ethnography of
environmental discourse. The Australian Journal of Anthropology.7(1): 43-66.
Michael R. Dove and Carol Carpenter.2007.Environmental Anthropology: A
Historical Reader.Blackwell publishing.
Sample Questions
1) Distinguish between Ecological and Environmental anthropology?
2) Describe briefly about theoretical perspectives and current approaches in
Ecological Anthropology?
3) Define EnvironmentalAnthropology and its scope?
4) Discussthe aspects of anthropological engagements with environmental
discourse?
5) How did environmental anthropology emergence explain?
23
History and Development of
Environmental
Anthropology
UNIT 2 BASIC CONCEPTS OF ECOLOGY
Contents
2.1 Introduction
2.2 What is Environment and Ecology?
2.3 Ecosystem Development
2.4 Community and Population
2.5 Habitat and Ecological Niche
2.6 Homeostasis of the Ecosystem
2.7 Ecological Succession
2.8 Summary
2.9 References
Suggested Reading
Sample Questions
Learning Objectives
After reading this unit, you will understand:
• the difference between environment and ecology;
• how does ecosystem develop;
• how community and population understand environmental anthropology;
• the habitat and ecological niche;
• homeostasis of the ecosystem; and
• the ecological succession.
2.1 INTRODUCTION
Understanding ecology is very important to the understanding of man’s future. It
provides the basis for considerable utilisation of natural resources facilitating in
the conservation of habitats and species, and also for the prediction on reflection
of man’s activities on natural environment. This clearly explains that ecology is
concerned with relationships between living organisms: plants, animals,
microorganisms and their environment. Ecologists study the way in which
organisms, populations, communities and ecosystems function and in doing so
encompass many other areas of knowledge.
2.2 WHAT IS ENVIRONMENT AND ECOLOGY?
Before going to know the other fundamental concepts, it is important to first
understand the meaning of terms ‘Ecology and Environment’. The term ecology
or “oekologie” formed by two Greek words oikos and logos which mean “study
of household” was coined by the German Biologist Ernst Haeckel (1866). Ecology
in most simple term refers to the branch of science that studies the interactions
between organisms and their environment. What is this interaction? It is with
&
24
Introduction to
Environmental
Anthropology
habitat, climate, geology and other aspects of its surroundings. The environment
of an organism includes both its physical habitat, which is described as the sum
total of all local factors like climate and geology, as well as other organisms
which share its habitat. To follow ecology it is imperative to understand the
fundamental concepts of biological ecology that the basis of its foundation. The
branch of social sciences which is concerned with the study of relationships
between human groups and their physical and social environments is referred to
as Human Ecology.
Ecology in the most common sense symbolises the dynamic interrelation of the
community with its total environment. Adjustments required for successful
existence in a particular habitat are adaptations. The term ‘Ecology’ which has
its root in the Greek word, came into use in the latter part of 19th century in the
works of biologists to describe the study the ways in which organisms live in.
their environments. Haekel coined our modern understanding of ecology in 1870,
defining it as “the study of the economy, of the household, of animal organisms.
This includes the relationships of animals with the inorganic and organic
environments, above all the beneficial and inimical relations Darwin referred to
as the conditions for the “struggle of existence” (Netting, 1977). Therefore, an
ecosystem concept consists of organisms acting in a bounded environment.
Whereas the term ‘environment’ is derived from the French words ‘environ’ or
environner’ meaning ‘around’, ‘round about’, ‘to surround’, “to encompass”. In
the dictionary sense, ‘environment’ is the total of things or circumstances around
an organism, which include its nature. What do we understand by the
environment? Broadly speaking, environment with seamless expanse comprises
of surroundings within which the population under consideration functions.
Environment in simple terms is multifaceted set of physical, chemical, biological
and social factors where a living organism or community exits. Environment
plays a significant role in influencing the growth and outlook of people living in
it. It also includes the built-in world of human creation to fulfill our need.
Environment is the setting for, or surrounding of all human interactions in society.
Environment, according to United Nations (1978) consists of natural and manmade
resources available at a given time for the satisfaction of human needs. It
is the totality of all external conditions and influences, both natural and cultural
influencing the life and development of human beings at any point in time on the
earth surface (Olorunfemi & Ajibade, 2000).
Abiotic and biotic form the two primary components of environment in ecosystem.
Environment and ecosystem though are at times used interchangeably but are
not the same. Environment is the surrounding in which a person lives whereas
ecosystem can be compared to a community, functioning with an environment
building one big unit. Environment is total surrounding of an organism but that
necessarily does not mean any ecological relationship between the members while
ecosystem is a definite ecological unit comprising of living and non-living
components that functions together as a system.
The abiotic component is the inorganic materials present in the environment i.e.
oxygen, nitrogen, sodium, carbon, as well as water and carbon dioxide alongside
the physical factors like weather, climate, temperature, radiation, light, geological
materials, geography, time, solar radiation and even the cosmos. What are the
biotic components? They consist of all materials that are biological in origin:
25
plants, animals, and microbes, either living or dead. Let’ Basic Concept of Ecology s take tree as an example
to understand these components; it forms part of the biotic environment, even
when dead, fallen or decomposed. Ultimately, when the tree is broken down into
its inorganic constituents, it enters the abiotic environment. Any variation in one
ecological or environmental factor can simultaneously reflect the dynamic state
of the whole ecosystem.
Environment has varied definition based on any number of reasons and operational
definitions. Environment too has different conceptual meanings like ecology
and to many these expressions also overlap with the concept of nature.
Distinguished on the basis of scale, two basic divisions of the biotic environment
are biomes and ecozones. Biome is a widened region which is characterised by
similar temperature, rainfall, and biology. Anthropologists use this concept as a
general descriptive category and as an initial stage for classification and analysis.
Whereas ecozone or environmental zone, is a geographic area distinguished by
definite biotic communities. Dominant plant communities define the ecozones
generally since it is easier to recognize and map them than animals. “Pine belt,”
is a typical example of ecozones.
An ecotone is the geographic intersection of as well as the transition between
ecozones. Since ecozone boundaries may also be biome boundaries, ecotones
exist between biomes as well. For example ecotone include estuaries (places
where freshwater meets saltwater, such as where a river empties into the ocean),
shorelines, and areas where forests and grasslands meet. An ecotone is usually a
more productive place than either of the individual ecozones because species of
both zones intermingle within it. Even in cases where there is less diversity, an
ecotone is a good place for an organism to be located as access to both ecozones
is easier. This same concept could be applied directly to cultural systems, where
the border between two cultures would form a cultural ecotone. This might create
a more “culturally productive” place, where ideas and goods could intermingle.
Examples of such places would be trading centers, ports, and centers of learning
(Mark Q. Sutton and E. N. Anderson, 2010).
Most biomes and ecozones are defined based on the current distribution of plants
and animals. Researchers studying past environments also use the ecozone concept
but define an ecozone based on past biotic distributions. Occasionally, a remnant
of a past biome or ecozone will survive into the present as sort of a living fossil.
These areas, and the life within them, are called refugia and can be quite valuable
in the study of past environments. For example, a number of desert regions once
contained different vegetation. If a small pine forest was found on top of a
mountain now within a desert, the forest may be a surviving remnant of a larger
forest that once covered the area. This refugium could provide clues to the past
plant and animal life within the region and provide a starting point for the
reconstruction of the ecozone at that time (Mark Q. Sutton and E. N. Anderson,
2010)
2.3 ECOSYSTEM DEVELOPMENT
Ecosystem is noticeably a geographically restricted system where a particular
group of organisms interact with both the components of the environment, abiotic
and biotic. The magnitude of ecosystems is dependent on how and why it is
defined. Presently biosphere occupies the position of largest ecosystem.
26
Introduction to
Environmental
Anthropology
It goes to the credit of Odum (1953) who formalised the concept of the ecosystem,
and Golley (1993) with the history of the idea. Ecosystems essentially have
conceptual component, therefore are defined on context of reference. Say if you
are studying tundra region you would define it as an ecosystem and would find it
inhabited by a different sort of plants; which would form a community related to
one another in an overall symbiotic relationship. Similar would be situation for
various species, how they are related to one another, their population cycles, and
so on. However, it must be clearly understood that tundra or for that matter any
other ecosystem is linked to other things as well, thus being a part of a larger
system.
Ecology spans a broad spectrum of interacting levels of organisation right from
micro-level (e.g., cells) to planetary scale (e.g., ecosphere) phenomena. Another
significant aspect – the time span is undefined in an ecosystem; it can take
thousands of years for ecological processes to mature through and until the final
successional stages of a forest. The area of an ecosystem can be from very small
to very big. While classifying a forest ecosystem a single tree holds no importance
but then it is of vital importance to the smaller organisms living in and on it. The
nature of associations in ecological communities cannot be elucidated by only
having knowing particulars of each species in isolation. This holds significance
because the developing pattern is neither discovered nor envisaged unless the
ecosystem is studied in totality.
Thus, we realise that ecosystems are defined at a variety of scales for different
rationale, but are eventually connected to one another. This creates the division
of ecosystems rather random. Interestingly, islands can be designated as “more
separate” ecosystem serving as better laboratories to study ecological interaction.
What could be the origin of ecology is quite complex since its interdisciplinary
nature has resulted in its multifaceted origin. It is unambiguous that Ancient
Greek Philosophers especially Hippocrates and Aristotle were amongst the first
ones to have recorded observations on natural history. Interestingly the ancient
Greek theorist are of belief that life is an unchanging element, in such a situation
there is no question of adaptation which primarily is the basis of contemporary
ecological theory.
In 1700s, with the published works of microscopist Antoni van Leeuwenhoek
and botanist Richard Bradley, modern concepts such as food chains, population
regulation and productivity were developed. Biogeographer Alexander von
Humbolt was also one among the early ecological thinkers and was pioneer in
recognizing ecological gradients. Ecology was an analytical form of natural history
evaluating the interaction of organisms with both their environment and their
community, during the early 20th century. Natural historians, including James
Hutton and Jean-Baptiste Lamarck, laid the foundation for noteworthy works
that placed the foundations of the modern ecological sciences.
The term “ecology” was first coined by the German biologist Ernst Haeckel in
his book Generelle Morphologie der Organismen (1866). Haeckel was not only
a zoologist, but was also an artist, writer, and later in life a professor of
comparative anatomy. There has been differing opinions about the founder of
modern ecological theory. Some perceived Haeckel’s definition as the beginning
of modern ecological theory, while others marked that it was Eugenius Warming
27
Basic Concept of Ecology from the writing of Oecology of Plants: An Introduction to the Study of Plant
Communities (1895). Carl Linnaeus’ research principals on the economy of nature
that matured in the early 18th century may also be noted as the beginning. His
works influenced Darwin and in The Origin of Species he adopted the usage of
Linnaeus’ phrase on the economy or polity of nature. Linnaeus was the first to
frame the balance of Nature to be a testable hypothesis. While Charles Darwin is
known for his theories on evolution, he is also credited as one of the founders of
soil ecology. In his book The Origin of Species Darwin also made note of the
first ecological experiment. With the gaining popularity of the theories of
evolution, there was scientific paradigm changed in the way researchers
approached the ecological sciences.
The modern synthesis of ecology first fascinated considerable formal concern
towards the end of the 19th century and became even more popular during the
1960s environmental movement, though many observations, interpretations and
discoveries relating to ecology go back to much earlier studies in Natural History.
Aristotle is designated as one of the earliest naturalists who had a prominent role
in the philosophical development of ecological sciences. Aristotle and his student,
Theophrastus made extensive observations on animal and plant biogeography,
migrations, physiology, and their habits what could be similar to the modern
ecological niche. Greek philosopher, Hippocrates, has also been recognized with
reference to ecological studies in its initial developments.
The first ecological text, Natural History of Selborne was suggested to be
published in 1789, by Gilbert White. In 1905, the first American ecology book
was published by Frederic Clements. His book promoted the idea of plant
communities as a super organism, which sprung a debate between ecological
holism and individualism that lasted until the 1970s. The Clements super organism
concept argued that ecosystems progress through regular and determined stages
of serial development that are similar to developmental stages of an organism
whose parts function to maintain the integrity of the whole. The Clement concept
was challenged by Henry Gleason who reasoned that ecological communities
develop from the unique and coincidental association of individual organisms.
This conceptual shift placed the focus back onto the life histories of individual
organisms and how it relates to the development of community associations.
The notion of food chains was initiated by Charles Elton in his classical book
“Animal Ecology”. Elton defined ecological relations using concepts of food
chains, food size, food cycles, and described numerical relations among various
functional groups and their relative abundance. Elton’s ‘food cycle’ was
substituted subsequently in ecological text by ‘food web’.
It is realised that eecology has spread its wings globally, but the inputs to ecology
from other cultures are hindered by language and translation hurdles.
2.4 COMMUNITY AND POPULATION
As we just read earlier that Ecology is the study of the interaction between living
things and their environment; and the relationships and interactions among
humans- their both aspects biological and cultural, and the physical environments
conceptualise human ecology.
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Human ecology is thus a study of total ecosystem with a stance specifically from
the viewpoint of human factor within the entire system. Humans are found in
any habitat be it cold tundra region or hot equatorial belt, consequently qualifies
human populations to be polytypic both in the characteristic of the population
and their ecological relationship.
It is imperative to study the complex relationship between man and the physical
setting in which they live to understand the environment. Man has made immense
contributions to environment. What we witness today are results of our scientific
and development strategies. Human-made Environment is the environment which
has been created by human himself to fulfill his needs and to make his life more
convenient and easy. There are many issues related to man made environment.
The consequence of poor environment directly affects the habitat resulting in the
formation of slums, heap of garbage, congested roads etc. The environment also
has pollution component in it. Air pollution, water pollution, noise pollution and
all other pollution do have an impact on human beings.
There are number of sources of energy which has an impact on the environment.
Solar, wind, hydro and tidal energy- the non- conventional methods of energy
sources are environment friendly whereas thermal power stations and nuclear
energy have negative environmental impact.
2.5 HABITAT AND ECOLOGICAL NICHE
The geographic setting where a species lives and functions is called its habitat.
Niche and habitat have a close relationship and are dependent on each other. Let
us take an example: some species of primates eat only fruit, while others only
leaves, and still others eat just about anything. Now all three species of primates
probably coexist in the same habitat yet occupying three different niches. In a
forest, on the same tree two different species may occupy different habitats, one
may live in the canopy while others live on the ground.
There have been many definitions of niche since 1917 but G. Evelyn Hutchinson
made conceptual developments in 1957 with the presentation of the most
extensively accepted definition, “which a species is able to persist and maintain
stable population sizes.” In the ecology of organisms, ecological niche is a central
concept and has been sub-divided into fundamental and realised niche.
Fundamental niche denotes the set of environmental conditions under which a
species is capable of persisting; where as realised niche signifies the set of
environmental plus ecological settings under which a species persists.
Each species have explicit functional traits that are entirely adapted to particular
ecological niche. Trait stimuli performance of an organism and is an assessable
property, phenotype, or characteristic. In the development and expression of traits,
it is the gene which plays a vital role. The appreciation of a species traits and
niche necessities are essential in elucidating or foreseeing the bio-geographical
patterns and range distributions. Occupant species develop their traits that are
tailored to their resident environment, which gives them a competitive advantage
and discourages comparable species adaptation from taking an overlapping
geographic range. This competitive exclusion principle proposes that two species
cannot coexist indefinitely by living off the same restrictive resource. Closer
examination into equally adapted species, found to overlap geographically
29
divulges elusive ecological dif Basic Concept of Ecology ferences in their habitat or dietary requirements.
The ecotope which combines both habitat and the niche is a complete range of
environmental and biological variables having an impact on entire species.
Niche is defined by the species activity, what it eats and by how it reproduces
whereas habitat is the geographic location of a species in which it lives and
operates. Habitat and niche are interrelated and dependent to some extent on
each other since the nature of habitat will influence the probable niches there.
Ecosystems contain numerous niches. Even though several organisms may be
competing to occupy a niche, it is specific and can be engaged by only one
organism in the same geographic place, which would serve as habitat to a large
number of species in diverse niches. The same niche may be inhabited by different
organisms in different geographically isolated habitats.
What is Niche construction? It has been defined as the process and concept of
ecosystem engineering. Ecosystem engineers are defined as “…organisms that
directly or indirectly modulate the availability of resources to other species, by
causing physical state changes in biotic or abiotic materials. In so doing they
modify, maintain and create habitats.” Organisms are modifiers of their habitats,
though they are also subject to environmental pressures.
The terms niche construction is usually used in reference to the mechanism of
natural selection imparting forces on the abiotic niche. Ecosystem engineering
concept has motivated a new approval for the degree of influence organisms
encompassing on the ecosystem and evolutionary process.
Niches come into reality and go out as systems change. In a young forest, the
niche of a high-canopy leaf eater does not occur, so it would not work as habitat
to the animal. But as the forest develops, habitat apt for high-canopy leaf eater
comes into being, and then the niche survives, which may lead to their movement
and settlement into the niche in the new habitat or the niche may even remain
unused. On the other hand, an existing species may evolve and adapt to the
niche.
Human beings have succeeded in occupying and dominated most of the terrestrial
habitats. Through the use of modern technology, humans modify habitat to suit
their needs even creating artificial habitats like cities. Adding to adaptability it is
the ability of humans to quickly alter their practices and diet. Humans occupy a
very broad niche and modern human culture has created a new urban-industrial
niche to suit their requirements.
2.6 HOMEOSTASIS OF THE ECOSYSTEM
Homeostasis of the ecosystem is also acknowledged as a biological equilibrium;
in other words balance of Nature. Homeostasis is the state when an ecosystem
maintains a biological equilibrium between the different components. It continues
to change with the time and is not stationary yet it maintains a stability which is
sustained by the number of factors including the carrying capacity of the
environment and the capacity for recycling of the waste.
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The effect of density on the reproductive potential deals with the self regulation.
Feedback system plays an important role in the ecosystem in which one
component of ecosystem maintains check on the population of the other
component. There are positive or negative feedback systems. Positive feedback
is the increase in the population of the organisms at the different levels increases
the population of organisms at a lower level. For example, when there is an
increase in the population of plants it promotes to increase in the population of
herbivore animals. Now, it increases the population of frogs and birds. In the
same way, the increased population of insectivorous animals predates on the
herbivorous insect which is termed as the negative feedback.
2.7 ECOLOGICAL SUCCESSION
Ecological succession is a course of action by which a community gradually
transforms itself until a stable community is formed. This is the foundation in
ecology, and the alteration that occurs is comparatively expected formation of
an ecological community. The genesis of succession lies either by formation of
new, unoccupied habitat (e.g., a lava flow or a severe landslide) or by some form
of disturbance (e.g. fire, severe wind throw, logging) of an existing community.
There are two types of succession: Primary succession and Secondary Succession.
Primary succession is the chain of community transformation which takes place
on a totally new habitat which has never been colonized earlier e.g. a newly
quarried rock face or sand dunes. Whereas secondary succession is the chain of
community transformation which take place on a previously colonized, though
on disturbed or damaged habitat e.g. subsequent to felling trees in a woodland,
land clearance or a fire. Another distinguishing feature is that primary succession
begins in areas where no soil is initially present whereas secondary succession
begins in areas where soil is already present.
An Ecological succession is the process in which change in the structure of species
of an ecological community takes place over a period. This process results at
times in some species becoming abundant or appearance of a new species or
may some even fade away entirely from an ecosystem. This visible transformation,
over a period of time in what is living in a particular ecosystem is “ecological
succession”.
Now, the question arises why does this phenomenon of ecological succession
happen? We all will agree that every species need certain optimal environmental
situation which is complacent for its growth and reproduction. In such a situation
in a given ecosystem all those species which are most suited to conditions to
grow and reproduce will become abundant. This means if ecosystem’s set of
environmental conditions remain unchanged, the species which are the best
adapted to those conditions will prosper. The original environment may have
quite conducive for first species be it plant or animal, but the modified
environment is often conducive for some other species of plant or animal. With
the change in the condition of the environment, the earlier dominant species
may not prosper and another species may increase.
Another scenario when the ecological succession may occur is when the
conditions of an environment unexpectedly and severely change. The conditions
like forest fires, wind storms, and human activities like agriculture contribute
significantly in modifying the conditions of an environment. These colossal forces
31
are capable of wiping out of species thereby altering the dynamics of the prompting Basic Concept of Ecology
a rush for dominance among the species still present in the ecological community.
The concept of succession holds importance. There is a very well defined and
predictable pattern through different stages of development until the final stage
each with differing measure of efficiency and diversity as a community evolves.
The stages of succession are concerned with the classification system of a definite
group and its use of the environment. For instance some faction of present-day
Maya believes that there are six stages of forest regrowth once the land is cleared
for agriculture. This becomes significant in appreciating the succession and its
allied agricultural implication which are critical to the timing of reuse of the
land for agriculture. The processes involved in succession would be the same;
however, the actual species involved in the process in a specific area are influenced
by Geology and History of the area, the climate, microclimate, weather, soil type
and other environmental factors. The time period of succession is not definite
and may vary in timescales, ranging from a few days to hundreds of years. It
takes hundreds of years for a succession of climax woodland to develop, whereas
the succession of invertebrates and fungi within single cow dung may be over
within as little as 3 months- the dung would have been changed into humus and
nutrients and recycled back into the soil. The holes evidently observable in the
cow dung are result of animals which have colonized it.
Is man affected by ecological succession? The answer is in the affirmative.
Ecological succession is not man-made but a power of nature. Ecosystems as we
understand are in continuous state of change and restructuring. Let us take an
example to appreciate how ecological succession affects humans and realise the
unbelievable time and money involved in ecological succession. Imagine a newly
ploughed garden plot. The land has been cleared by preparing the soil for new
planting has resulted in the disruption and restructuring of the earlier stable
ecosystem- this is major external event executed by man. The disturbed ecosystem
will without delay begin the progression of ecological succession.
Does ecological succession reach the stage of standstill?
There is a notion in ecological succession termed as the “climax” community.
Earlier school of thought was of the opinion that ecological succession finally
culminated having a stable end-stage called the climax. This proposal has been
discarded by modern ecologists in support of non-equilibrium ideas of how
ecosystems function. The climax community characterises a steady end product
of the succession sequence. There are certain species in plants that maintain
itself for a very long time i.e. their structure and composition would not alter
noticeably over an observable time. We can to this extent believe that ecological
succession has stopped. But then, it is a known fact that any ecosystem to whatever
degree it may be naturally established and constant; is susceptible to substantial
external upsetting forces like fires and storms that could reorganize and re-start
the succession process. Till these probable calamities exist, it is incorrect to
believe that succession has stopped. One point to be appreciated is that over
long periods of time there is a change in the climate conditions and other original
characteristics of an ecosystem. These changes are not evident in our “ecological”
time, but it is certain that their fundamental existence and historical reality is not
doubtful. Hence, no ecosystem whether it is past or future will continue living
unaffected or fixed over a geological time scale. Let us take concept of climax
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vegetation: subsequent to a forest burns; there are different stages of succession
which vegetation goes through. They include the grass and herbs, then shrubs
and vines, then weedy trees and finally the “climax forest” that grows up under
the weedy trees. The climax vegetation goes on until the next fire. However,
there is never so simple and static model.
Plant species adapted to the changed soil conditions would dominate the scene.
It is mostly the weeds that has significant ecological role and functions, take
over. However weeds are vying amid the garden plants for nutrients, water and
physical space. The garden would soon be infested with weed that are intensely
productive and the garden plants would struggle to strive if left unattended. The
only way to combat the situation is weeding the garden which requires lot of
time and energy. Now, this energy contribution is directly proportional to the
“energy” inherent in the force of ecological succession. Imagine, if this small
scale situation is applicable to all the agricultural fields and systems on Earth,
then how much load would be there for all of the farmers and gardeners who are
growing our food. This gives an idea of the huge cost in terms of time, fuel,
herbicides and pesticides that we pay every growing season because of the force
of ecological succession.Ecology has spread its wings globally, but the inputs to
ecology from other cultures are hindered by language and translation hurdles.
2.8 SUMMARY
Ecology plays a significant role for considerable utilisation of natural resources
facilitating in the conservation of habitats and species, and also for the prediction
on reflection of man’s activities on natural environment. Ecology refers to the
branch of science that studies the interactions between organisms and their
environment. Ecology in the most common sense symbolises the dynamic
interrelation of the community with its total environment. Environments have
both abiotic and biotic components in which all organisms interact. Environments
can be defined based on any number of criteria, and operational definitions differ
depending on the situation. There are two basic divisions of the biotic
environment, biomes and ecozones, differentiated based on scale. A biome is a
large-scale, broad region of similar temperature, rainfall, and biology. An
environmental zone, or ecozone, is a geographic area defined by fairly specific
biotic communities within biomes.
An ecosystem is a geographically bounded system within which a defined group
of organisms interact with both the abiotic and biotic components of the
environment. Each species occupies a niche, the role it plays within its
environment, community, or ecosystem. A niche is defined by what the species
eats, how it reproduces, and what it does. The geographic location where a species
lives and operates is called its habitat. Niche and habitat are interrelated and
somewhat dependent on each other as the type of habitat will influence the possible
niches present. Adjustments required for successful existence in a particular
habitat are adaptation. The magnitude of ecosystems is dependent on how and
why it is defined. Presently biosphere occupies the position of largest ecosystem.
They are defined at a variety of scales for different rationale, but are eventually
connected to one another. Niche and habitat have a close relationship and are
dependent on each other. Through the use of modern technology, humans modify
habitat to suit their needs even creating artificial habitats like cities. Homeostasis
33
of the ecosystem is also acknowledged as a biological equilibrium; in other words Basic Concept of Ecology
balance of Nature. Ecological succession is a course of action by which a
community gradually transforms itself until a stable community is formed and it
is the process in which change in the structure of species of an ecological
community takes place over a period. Lots of work has been done all around the
world, but the inputs to ecology discipline from other cultures are hindered by
language and translation hurdles.
2.9 REFERENCES
Mark Q. Sutton and E. N. Anderson. 2010. Introduction to cultural ecology. A
division of Rowman & Littlefield Publishers, Inc.
Suggested Reading
Hardesty, Donald L. 1975. The Niche Concept: Suggestions for Its Use in Studies
of Human Ecology. Human Ecology 3(2):71–85.
Odum, Eugene P. 1953. Fundamentals of Ecology. Philadelphia:W. B. Saunders.
Kormondy, Edward J., and Daniel E. Brown. 1998. Fundamentals of Human
Ecology. Upper Saddle River, NJ: Prentice Hall.
Richerson, Peter J. 1977. Ecology and Human Ecology: A Comparison of Theories
in the Biological and Social Sciences. American Ethnologist 4(1):1–26.
Sample Questions
1) How ecological developments take place?
2) What is the difference between Habitat and Ecological niche?
3) Define Environment and Ecology.
4) Discuss ecological succession.
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Anthropology
UNIT 3 HUMAN BIO-CULTURAL
ADAPTATIONS
Contents
3.1 Introduction
3.2 Emergence of Primates
3.3 Primate Ecology
3.4 Primate Behaviour and Social Structure
3.4.1 Dominance
3.4.2 Aggressive Behaviour
3.4.3 Affiliative Behaviour
3.4.4 Communication
3.4.5 Tools and Culture
3.5 Human: Bio-cultural Adaptation
3.5.1 Response to Heat
3.5.2 Response to Cold
3.5.3 Response to High Altitude
3.6 Summary
3.7 References
Suggested Reading
Sample Questions
Learning Objectives
After going through this unit, you will be able to:
• recognize the basic ways humans adapt to different environments;
• describe the various environmental pressures which shape the primate’s
behaviour; and evaluate various bio-cultural activities adopted as adaptive
strategies by human; and
• apply anthropological perspectives on human evolution and adaptation to
theories of human-habitat interaction from Biological and Cultural Ecology.
3.1 INTRODUCTION
Darwin’s publication “On the origin of species” has crystallised the understanding
of the evolutionary process revealing natural selection as the key to evolution. In
the struggle for existence the individuals with favorable variations were selected
for survival by nature while unfavorable were eliminated. From genetic
perspective evolution is defined as change in allele frequency from one generation
to the next. The mechanism of evolutionary changes produced by natural selection
can be summarized as:
a) A trait must be inherited from parents.
b) Natural selection acts on existing variation within species which is potentially
impasse without inheritance of characteristics.
&
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Human Bio-cultural
Adaptations
c) Fitness is relative measure that will change as the environment changes.
Better adapted individuals generally produce more offspring over
generations, thereby the frequency of adaptive trait generally increase in
subsequent generations. A new species emerge when changes in trait or
geographic barrier result in reproductive isolation of the population.
In the context of ‘Modern Evolutionary Theory’, evolution may be defined as
two stage process:
a) The production and redistribution of variation (inherited differences between
individuals). As for speciation, the development and divergence of different
species would occur when sub-populations become isolated by geographic
barriers or when different subpopulation encountered different climatic
conditions or moved into new ecological niches, those environmental
isolating process would eventually result in the development of reproductive
isolation and new species.
b) Natural Selection acts on these variations whereby inherited differences or
variations among individuals differentially affect their ability to reproduce
successfully.
The evolutionary factors – mutation, gene flow, genetic drift & recombination
interactively affect the gene frequency & produce variation within and between
populations. Though these evolutionary changes can occur even in absence of
natural selection, directional evolutionary trends have been sustained only by
natural selection.
Anthropologists today are concerned with human variation because of its adaptive
significance and to elucidate the genetic and related evolutionary factors that act
to produce variation. In other words, many traits that typify certain populations
are seen as having evolved as biological adaptation or adjustments to local
environmental conditions (including infectious diseases). Thus, human presents
the contemporary component of vast biological continuum. They share a common
ancestry with modern African apes since 6-8 million years ago. Evolutionary
approach correlates specific aspects of primate social structure with the elements
of their habitats, since all living organisms must adapt behaviourally as well as
physically to their environment. By elucidating the various environmental
pressures involved and understanding how they have influenced non-human
primate behaviour, we can better comprehend the factors that led to human
emergence.
3.2 EMERGENCE OF PRIMATES
Primate displays a wide range of behaviours and social organisations that vary
from species to species as well as within species under different environmental
situations such as predation intensities and population densities (Swindler, 1988).
It is generally agreed that the primates may have emerged by the Paleocene, 65
million to 55 million years approximately and perhaps earlier in late Cretaceous
climatic changes due to continental drift that had profound effect on the evolution
of primates. Expansion and diversification of deciduous trees and flowering plants
probably led to mammalian expansion and diversification. Primates evolved from
one of these mammalian radiations, probably from the insectivora order of
mammals that was is adapted to eating insects.
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The traditional view of primate evolution was that arboreal life would have
favored many of the common primate features such as dentition, greater reliance
on vision over smell, three dimensional binocular vision and grasping hands and
feet. Alternatively, Cartmill’s visual predation theory (1974) proposes that the
distinctive primate character were selectively advantageous for hunting insects
on the slender veins and branches that filled the undergrowth of Tropical forests.
Robert Sussman’s theory, conceal that the basic primate traits have arisen in
response to fine visual and tactile discriminate necessary locating flowers, fruits
and seed on slender branches in dim light.
3.3 PRIMATE ECOLOGY
Primates occupy all the seven continents – Africa, Asia, South America, Europe,
North America Australia, Antarctica and the nearby islands. Although primates
occupy only marginal areas of Europe (Gibraltor) and North America (Central
and Southern Mexico), they were formally wide spread on both the continents.
Within this geographic range, living primates are found in a variety of habitats,
ranging from deserts to tropical rain forests. Despite, they are largely restricted
to the tropical forested regions of Central and South America, Sub – Saharan
Africa, Madagascar and Southern Asia. Each of these bio-geographical regions
has a distinctive climate, topography, geology, flora and fauna. In a tropical forest
which reaches a height of 80 m; the temperature and humidity, the kind of plant
food, shapes of branches, and the type of other animals a species encounters are
usually quite different on the ground level where they are subjected to inadequate
light and terrestrial predators (Fleagle, 1999). However, in higher canopy
horizontally spread branches provide convenient highways for arboreal travel
and abundance of leaves and fruits. Still higher in the emergent layer, the canopy
become discontinuous and heat from sun may be quite intense and primates are
exposed to aerial predators. Primates are gregarious and social animals. However,
not all primates are found in larger groups and solitarity in some species is
probably related to diet, distribution of resources and predator avoidance.
The nutritional requirements of animal are related to the body size and basal
metabolic rate. Smaller animals have high BMR than larger ones and require
energy rich diet rich in protein (insects), fat (nuts and seeds), and carbohydrates
(fruits and seeds). While larger primates don’t depend on high energy diet/food
and consume leaves, stems and other types. Insect on the other hand, may be
widely scattered and the animals that rely on them usually feed alone and in
small groups of 2 or 3. Fruits, nuts and berries in dispersed trees and shrubs
occur in clumps. They can most efficiently be exploited by smaller groups of
animals, so large groups frequently break up into smaller subunits may consist
of one male, multi female group and matrilines (a line of descent in which an
individual is considered to belong to the same descent group as her or his mother).
Species that feed on abundantly distributed resources may also live in one-male,
multi female groups and because food is plentiful, these units are able to join
with others to form large, stable communities which may appear to be multi
male and multi female groups.
In tropical forests attacks by birds of prey, cats, large animals and humans are all
potentials cause of mortality. Typically when predation pressure is high, large
communities are advantageous and when body size is small, large communities
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Adaptations
are advantageous. These may be multi male-multi female groups or congregation
of one male group. Most primates are diurnal, but several small bodied Prosimians
and New World Monkeys (the owl monkey) are nocturnal. Nocturnal primates
tend to forage for food alone or in groups of two or three and many use
concealment to avoid predators.
Thus, procurement of food and avoidance of predation are the basic requisites of
life as a primate. These as adaptive strategies influences the social structure and
behaviour of the species. The complex social organisation has evolved through
the process of natural selection. It enhances protection from predators, wider
access to mates, better reproductive success and assistance in raising offspring
and better access to food resources. They participate in a number of activities to
reinforce the integrity of groups which can be summarized as follows:
3.4 PRIMATE BEHAVIOUR AND SOCIAL
STRUCTURE
3.4.1 Dominance
As most of the primate lives in groups, they compete with one another from time
to time for food and mates. This result in establishment of dominance hierarchy
that involves individual differences in behaviour based on size, age, sex, status
and kinship. It imposes a certain degree of order within groups by establishing
parameters of individual behaviour, thereby reducing causes of intergroup
agonistic behaviour (Jurmain et al., 2006). Dominant animal exerts control over
aggressive behaviour of other animals by making a dominating, threatening
gesture or behaviour. Higher ranking individuals have greater access to preferred
food items and mating partners than lower ranking individuals. Dominance
hierarchies have sometimes been referred to as “Pecking Orders”. Dominance
increases the reproductive success of the animal. Higher ranking females have
greater access to food than subordinate females and are provided with more
energy for offspring production and care (Fedigan, 1983) For instance, offspring
of high ranking female chimpanzee at Gombe National Park , Tanzania had
significantly higher rates of infant survival. Their daughter matured faster
indicating shorter inter-birth interval and consequently produced more offsprings
(Pusey et al., 1997).
Males are usually dominant over females. However, in multi female groups
associated with one or several adult males, males and females have separate
hierarchies. Although very high ranking females can dominate the lowest ranking
males and among many species female are dominant sex (lemur) or among species
that form monogamous pairs, males and females are co-dominant (eg. Indris,
gibbons). An individual’s position in the hierarchy is not permanent and changes
throughout life. It is influenced by factors including sex, age, level of aggression,
amount of time spent in the group, intelligence and sometimes the mother’s
social position (Jurmain et al., 2006).
3.4.2 Aggressive Behaviour
Primate groups are associated with a home range where they remain permanently.
The sizes of the home ranges vary considerably for a variety of ecological and
social reasons such as size and proximity of neighbouring troops and the
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Anthropology
concentration of food plants. Within the home range is a more restricted area
called the core area, which contains the highest concentration of predictable
resources, and here the group is most frequently found. Although parts of a group’s
home range may overlap with the home ranges of other groups, core areas of
adjacent groups do not overlap. These area are exclusively used by the group is
said to be a group’s territory which is defended against intruders and can lead to
outright aggressive behaviours. Similarly, conflict within a group frequently
develops out of competition for resources, including mating partners or food
which often leads to such behaviours. Most intragroup aggression occurs in the
form of various signals and displays, frequently within the context of a dominance
hierarchy. Therefore, the majority of tense situations are resolved through various
submissive and appeasement behaviours. However, all conflicts are not resolved
peacefully and frequently results in injury and even death. For instance, male
chimpanzees are highly intolerant of unfamiliar chimpanzees, especially other
males, and they fiercely defend their territories and resources. Intergroup
interactions are almost always characterised by aggressive displays, chasing, and
frequently actual fighting.
3.4.3 Affiliative Behaviour
A certain amount of aggression maintains order within groups and protects
resources. However, to minimise actual violence and to defuse potentially
dangerous situations, there are many behaviours that reinforce bonds between
individuals and enhance group stability. These affiliative behaviours include
reconciliation, consolation, and simple amicable interactions between friends
and relatives (Jurmain et al., 2006).
a) Grooming
Grooming is a tactile activity practiced by all primates from prosimiams to
great apes whereupon the groomer inspect the skin of the groomee, picking
off piece of dirt, flakes of skins, and any ecto-parasites that might be present.
This hygienic behaviour in time has developed into a much more important
social behaviour preserving group stability and solidarity. It reduces tension,
reinforce social relationship, dominance hierarchy and proximity between
the primates. Grooming takes place more often among related than among
nonrelated individuals in many primate species and infants usually receive
more grooming than older offsprings. Prosimians use their tooth combs
(lower incisors and canines) and toilet or grooming claws (on the second
digit of the foot) for grooming. They seem to use dental comb when grooming
other individuals and generally reserve their grooming claws for cleaning
and maintaining their own fur (Swindler, 1988)
b) Altruism
Altruistic act involves some risk or sacrifice to the performer to protect
others from attacks by conspecifics or predators. The protection of dependent
offspring, is ubiquitous who may or may not be related to the performer.
Stelzner and Strier (1981) witnessed a female baboon chasing a hyena that
was in pursuit of a young adult male baboon. Adoption of orphans has been
reported for macaques, baboons, and gorillas, and it is common in
chimpanzees. When chimpanzee youngsters are orphaned, they are almost
always adopted, usually by older siblings who are solicitous and highly
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Adaptations
protective. Empathy, or the ability to identify with the feelings and thoughts
of another individual, is required for altruistic behaviour. Evolutionary
explanations of altruism are usually based on one of two premises: First,
individuals perform acts that benefit others because they share genes with
the recipient; thus, by helping a relative, the performer is helping to ensure
the survival of the genes they have in common. The second explanation,
sometimes called “reciprocal altruism,” is that one individual helps another
to increase the chances that, at a future date, the recipient might return the
favor (Jurmain et al. 2006).
3.4.4 Communication
Communication in primates refers to scents and unintentional, autonomic
responses and behaviours that convey meaning. These include a wide variety of
gestures, facial expressions, and vocalisations.
a) Olfactory: The odors of pheromones secreted by the scent glands in various
areas of the body eg armpit, along forearm or near the base of tail are generally
used for sexual interaction. In many species the males smell the anoperineal
region of the female or even examine her vagina to monitor her reproductive
status. At height of estrus there may be several males following one female.
Other than sexual attraction, many primates use scent markings to establish
territories, as alarm mechanisms and in aggressive encounters.
b) Visual signals include body postures, gestures, facial expressions and
different positions of tail. These ritualised visual behaviours stimulate both
friendly and competitive interactions. The social relationships are manipulated
by reducing tension within a group and maintaining cohesion by preventing
fights. For instance, during a series of displays by dominant male macaque,
the subordinate animal can terminate the action by performing a conciliatory
gesture such as presenting its rear end to the dominant male. Rhesus monkey
display dominance by holding the tail high above the body with a slight Scurve
near the end, while a lower rank male carries his tail low below the
level of his back while walking. Facial expressions such as yawn is a threat
signal particularly when the upper canines are exposed (eg. baboons). Lip
smacking often accompanied by tongue thrusting is an invitation to approach.
The play-face is often a friendly gesture in which an animal looks towards
another animal with open mouth but don’t stare while staring makes it a
threat gesture.
‘Sting-fight’ among lemur presents an interesting illustration of both olfactory
and visual communication. The males rub their chests and forearm scent
glands together stimulating the flow of pheromones, and then rub their tails
through their forearms and across theirs chest, after which they quiver and
shake their tails at their adversary, who receives an odiferous blast from the
waving tail. This results into withdrawal of troops to favorable positions
and escape from the enemy (Swindler, 1988).
c) Auditory: With evolution, enhanced visual communication along with
vocalisation among diurnal primates has replaced the varied olfactory signals
of the nocturnal Prosimians. The warning calls of the arboreal species alert
the members of the group of impending danger from a bird or snake eg.
Vervet monkeys. Chimpanzee makes pant-hoots vocalisation during feeding,
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Anthropology
when groups meet or when they begin to nest in the evening. Howler monkeys
probably have 15-20 separate vocal patters in their repertoire. It includes
hoarse clucks that initiate troop movements, gurgling sounds made only by
males as defensive vocalisation and the wailing sounds made by a mother
when her infant has fallen or otherwise been removed from her. The ‘great
call’ among gibbon serves to identify the boundaries among gibbon territories
and is unique for each species. As they approach near another group, the
two groups engage in a vocal battle that becomes louder and faster until one
group moves away thus lessening the chances of actual physical contact
(Swindler, 1988).
3.4.5 Tools and Culture
Many animals were known to use unmodified objects as tools but fabricating
tools was the unique activity of the genus Homo. However, chimpanzees have
been found to make and use tools as probes for termite fishing. These tools have
usually been modified by stripping off the leaves or breaking the twigs into
different shapes for later use at termite mounds. The termites attach to the stick
inserted into the hole and when it is removed, the chimpanzee licks off the
termites. In addition to termite fishing, the repertoire of chimpanzee cultural
behaviours include nest building, hunting and throwing sticks and stones as
offensive weapons. Tools use has been reported occasionally among the wild
orangutans such as waving sticks to ward off wasps or to scratch one’s back.
Washing of sweet potatoes in nearby sea portray the cultural behaviours among
the primates (macaques). The sweet potatoes were not only cleaned by the washing
but the monkeys preferred the added taste of salt.
3.5 HUMAN BIO-CULTURALADAPTATION
Humans have occupied a wide range of habitats because of their ability to
intervene environment- the living and inanimate, for their purposes. This approach
is largely based on a notion of adaptability, which regards individuals as being
equipped with a set of biological traits that provide means of survival within
certain limits. It involves physiological, structural, behavioural or cultural changes
aimed at improving the organism’s functional performance in the face of
environmental stress. These adjustment can either be temporary or permanent,
acquired either through short term or lifetime processes. Thereby expressed in
terms of phenotype variation of continuous trait, physiological acclimatisation
and learned behaviour. There seems to be few situations in which human
population develop genetic adaption to specific environment expressed in terms
of phenotypic variation which eventually leads to differences in allele frequency
between populations. On the other hand, decades of research affirm that biological
plasticity or physiological acclimatisation is species wide adaptive mechanisms
which enable individuals to maintain internal constancy or homeostasis. These
adaptive strategies represent the continuum and elaboration of adaptive patterns
which characterise primate.
Within the broader content of Human Evolution coping with ecological constrains
include culturally coded survival strategies. Culture is a complex entity of
technological inventiveness, social institutions, belief systems and idiosyncratic
amalgamation with our evolutionary biological and behavioural heritage. It
includes technology which range from computers, subsistence pattern ranging
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Human Bio-cultural
Adaptations
from hunting and gathering to agri-business on a global scale, housing type from
thatched huts to skyscrapers and clothing from animal skin to high tech synthetic
fibres (Jurmain et al., 2006).
“the use of human population in ecological analyses preserves a view
of humanity as a part of nature at the same time that it recognizes the
uniqueness conferred upon the species by culture. As such it preserves
the terms defining the condition of a creature that can live only in terms
of meanings, largely culturally constituted, in a world to which law is
intrinsic but meaning is not.” (Rappaport, 1990)
Culture is learned and passed on from one generation to the other. It shapes
people’s perception of external environment in particular way that distinguishes
one culture from another. It is, however, important to emphasise that culture is
not genetically determined and the human predisposition to assimilate culture
and function within is influenced by biological factors. Indeed, over the past
several million years of human evolution, biology and culture have interacted in
such a manner that human are said to be the product of bio-cultural evolution.
Thus the aspect of human variation includes the bio-cultural response of
population to different kinds of environmentally induced stress i.e high attitude,
cold and heat.
3.5.1 Response to Heat
Human maintain a relatively constant internal body temperature independent of
environmental temperature through a complex mechanism of heat gain and heat
loss. In hot climate, the fundamental response of human exposed to heat stress is
heat dissipation. The process of heat transference between the body and
environment includes radiation, conduction, convection and evaporation. It has
been observed in all human to an almost equal degree, with the average number
of sweat glands per individuals (approx 1.6 million) being fairly constant.
However, the non-acclimatized individual, on exposure to heat stress exhibits
significantly increased perspiration rates (Frisancho, 1993). Further, the effectiveness
of the heat removal process depends, on the gradient of heat between the body
core and the external environment which involves three factors:
1) The magnitude of heat gradient between the environment and body core.
2) The rate of heat exchange between the interior and skin surface.
3) The rate at which metabolic heat is produced.
People from the hottest regions (South Asia, Africa, India and Australia)
had the largest surface area to body mass ratios. Such a morphological
configuration is ideally suited to the more energy-efficient dry heat exchanges,
and to a reduced reliance upon evaporative cooling (Taylor, 2006).
Another adaptive mechanism involves vasodilation, whereby blood capillaries
near the skin surface widen to permit increased flow to the skin and hence
enhanced peripheral heat conductance.
Skin color is another adaptive mechanism to the distinct climatic conditions.
Melanin pigment produced by melanocytes present beneath the epidermis
provides protection from overexposure to ultra violet radiation which can cause
genetic mutation in skin cell leading to skin cancer.
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Anthropology
Thereby, natural selection has favored dark skinned individuals in area near the
equator where exposure to UV radiations is the most. Biotopes with high densites
of UV radiation are also characterised by high temperature. In such biotopes a
dark skin color would actually be disadvantageous, as it causes a strong heating
of body surface, due to relatively low reflectance. This is explained by differences
in numbers and function of the sweat glands among dark skinned individuals.
The African groups have been able to maintain a lower body and skin temperature
as compared to European light skinned people as a consequence of lower
suppression of sweat rate than Europeans (Walter, 1971). Thus darkening of
skin is of prime biological importance so not only in Negroid, but a functionally
effective melanisation is present in South Indians and other ethnic groups also
(Weiner, 1964).
Cultural adaptation
It pertains to the creation and maintenance of favorable environmental conditions
near the individual – microclimate, different from those in the general area. The
ideal microclimate involves lowered skin temperature, a vapour pressure gradient
favoring evaporative heat loss, and protection from conductive, convective and
radiation heat gain.It is within the extrasomatic zone that behavioural and social
adaptations play a major role by maintaining a favorable microclimate within a
larger and more stressful macroenvironment. (Hanna, 1983).
Material Culture as habitations and clothing establish a favorable microclimate
while behavioural adaptation centre’s largely upon avoidance. Houses are
constructed of high heat capacity materials such as adobe and stone, to delay
entry of heat. These materials absorb large amount of heat before passing it into
the interior and the stored heat is lost at night by radiation and convection. The
net effect is to dampen temperature fluctuation so that interior temperature remains
moderate. Pueblo Indians, Middle Eastern communities construct their house
several meters beneath the surfaces as the mean temperature of subsoil is more
comfortable that the surface with its extreme variation. In habitation above the
ground, compact geometry minimizing surface area to internal volume reduces
solar heat gain as well as convention heat gain from desert winds.
Clothing, another aspect of material culture reduces abrasions, prevents sunburn
and reduces solar heat gain. This in turn reduces level of perspiration required to
maintain equilibrium. It has been proposed that well-acclimatized individual
wearing clothes perspire 30% less than unclothed men at rest which reduces the
heat load of about 165 kcal/hr. (Henschel and Hanson, 1959)
Chaamba Arabs, tribal population of Sahara Desert wear clothing that minimises
conductive and radiant heat gains from the environment. The insulative effects
of trapped air reduce heat transmission to the skin surface. However, clothing is
less advantageous at work than at rest as it hinders the loss of internally generated
heat and loose fitting, baggy clothing is desirable. Such cases, favors ventilation
and evaporates from the skin surface. Furthermore, a light-colored external
garment may reflect radiation reducing heat gain.
3.5.2 Response to Cold
Human physiological responses to cold combine factors that increase heat
retention with those that enhance heat production (Jurmain et al., 2006). On
exposure to cold stress vasoconstriction limits the flow of warm blood from
43
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Adaptations
core to the skin thereby lowering the skin temperature. Consequently reduction
of temperature gradient between the skin surface and environment reduces the
rate of heat loss. The reduction in heat conductance of the blood is also caused
by deviation of the blood in the extremities from superficial vein to the deep
veins. The countercurrent heat exchange between arteries and vein lower the
heat conductance to the periphery.
In addition, subcutaneous fat layer provides an insulator layer throughout the
body. When vasoregulatory mechanisms are not sufficient to counteract heat
loss, the organism adjusts by increasing the rate of heat production. Shivering
augments the thermeogenesis of the muscle mass and the temperature of muscle
is raised to approach that of the core, thus eliminating the temperature gradient
heat loss (Frisancho, 1993) shivering also increase the metabolic rate to two
three times the basal value which consequently release energy in the form of
heat. In general, people exposed to chronic cold maintain higher metabolic rate
than those living in warmer climates. The Eskimo living in the Arctic maintain
rates between 13-45% higher that observed in non-Inuit.
Himalayan population of India wear several layers of cloth to combat cold, but
extremities remain exposed to cold stress. However, they are characterised by
elevated resting metabolic rate and high level of blood flow to the extremity to
maintain warm surface temperature during local exposure to cold (Little et al,
1977).
Body size and proportions are also important in regulating body temperature. In
general, within a species, body size increase with the distance from the equator.
Two rules that pertain to such relationship between body size, body proportion
and climate are:
1) Bergman rule
In mammalian species, body size tends to be greater in population inhabiting
colder climates. Increased mass, thereby decreased surface area allows greater
heat retention and reduced heat loss eg. Arctic region
2) Allen’s Rule
In colder climates, shorter appendages, with increased mass-to-surface ratios
are effective at preventive heat loss. Conversely longer appendages with
increased surface area relative to mass permit heat loss eg. Sub Saharan
Africans.
Cultural adaptation
The diurnal-nocturnal variation in the temperature exposes the Aborigines of
Australia to heat stress during day and moderate cold stress during night. As
they wore no clothing and did not built shelters, the heat against the cold stress is
provided by sleeping fires. They also experience continuous vasoconstriction
throughout the night which prevents them from excessive internal heat loss with
no threat of frostbite.
The Bushman of Kalahari Desert, like the Australian Aborigines are exposed to
moderate chronic cold stress during night. They have been able to create a
microclimate around their bodies that is close to the thermoneutral temperature
of 25°C through efficient use of fires and skin cloaks during cold nights
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Anthropology
(Frisancho, 1993). They sleep in a group of three or four in families or in single
sex groups. The heat made up of grass and boughs are placed in a half-circle as
wind breakers.
Eskimos occupy the northwestern coast of North America and across the Bering
Strait into Asia. They have well insulated housing known as ‘Igloo’. Their wall
made of whole rib rafters are covered with a double layer of seal skin attired
with moss. They place the source of heat usually an oil, blubber or coal lamp at
a lower level than the main floor; where by cold air is warmed before it reaches
the area where people live. The housing structure permits trapping of air which
in turn further provides insulation. Such an efficient heat exchange system
maintains between 10ºC to 21ºC for coastal Eskimos despite subzero
environmental temperature. Their clothing is made of caribou which provides
higher insulation as compared to seal skin. Coribou fur of 1½ and 3 inches
thickness provide insulation equivalent to 7 to 12 clo units (Scholander et al.,
1950) Although Eskimo wear snowshoes and short skin mittens at times, during
their daily activities such as fishing, their hands and feets are continuously subject
to cold stress. They experience intermittent periods of vasoconstriction and
vasodilation which prevent frost bite in below freezing temperatures. At the same
time, because vasodilation is intermittent, energy loss is restricted, with more
heat retained at body’s core. The high peripheral temperatures of extremities and
high tolerance to cold of Eskimos and highland Quenchas appear to reflect the
influence of developmental acclimatisation. Traditionally they have the highest
animal protein and fat diet than any other human population. Such a diet,
necessitated by the available resources base, served to maintain the high metabolic
rates required by exposures to chronic cold.
The highland Quenchua population from the Peruvian Andes and other mountain
areas of South America are exposed to a variety of stresses including hypoxia
cold, low humidity and high levels of solar radiations. Thus, interpretation of
cold adaptation of the highland population requires a synergic interpretation of
all these stresses. The success of the Quenchua population in preventing severe
body cold stress reflects the effectiveness of their technological adaptations, which
includes housing, bedding and clothing. The housing of the highland natives
differs with the variation in altitude and subsistence pattern. Population living
below 4000m has mixed economy owing to individual or community ownship
of land. They have permanent houses built of Abode which maintain the indoor
temperature more than 10ºC above the outdoor temperature. On the other hand,
housing at elevation above 4300m are temporary is a consequence of pastoral
economy requiring high mobility. However, these houses constructed of piled
stones and roofed with straw have inadequate insulative effectiveness with the
average indoor-outdoor differential temperature of 3.7ºC. They sleep within the
woolen sleeping bags providing adequate protection against cold stress. Clothing
results in 4ºC increase in temperature of the skin under clothing.
3.5.3 Response to High Altitude
A high attitude environment exerts multiple stresses on human which include
hypoxia, more intense solar radiation, cold, low humidity, wind, a reduced
nutritional base and rough terrain. Of these, hypoxia exerts greater degree of
stress on physiological functions and is not easily modified by cultural behavioural
practices or responses. Hypoxia results from a decrease in partial pressure of
45
Human Bio-cultural
Adaptations
oxygen in atmosphere proportionally to increase in the attitude which
consequently leads to reduction in O2
Heamoglobin saturation. It interferes with
the oxygen acquisition at the cardiopulmonary level and utilisation by the cells.
Hypoxia induced anorexia and dehydration due to increased ventilation and low
humidity at high attitude leading to weight loss. The multifaceted effect of hypoxia
also manifests through increased rates of infant mortality, miscarriage and
prematurity among people residing at higher elevation. Decreased foetal growth
due to impaired maternal foetal oxygen transportation also results into birth of
low birth weight babies.
Thus, acclimatisation to high attitude hypoxia is a complex phenomenon that
develops through the modification and synchronized interdependence of the
respiratory, circulatory and cardio vascular system to improve oxygen delivery
and utilisation. On exposure to high attitude low landers, acquire short term
modifications or partial acclimatisation in response to hypoxia which include
increase in respiration rate, heart rate, and production of RBC which contain
oxygen-transporting protein heamoglobin while high attitude dwellers adapt to
hypoxia during their lifetime, as they mature. During growth and development
environmental factors constantly condition and modify the expression of inherited
potentials. The environmental influences felt by the organisms depend on the
type of stress imposed and especially on the age at which the individual is
subjected to the stress. The respective contribution of genetic and environmental
factors varies with the development stage of the organism, in general (Frisancho,
1993).
The earlier the age or the longer the duration of stay at high altitude, the greater
the environmental influence on body dimensions and respiratory functions. For
instance, the altitude natives Anedean Indians have larger chests and greater
lung capacity as well as more surface areas in the capillaries of lungs which
facilitate the transfer of oxygen to the blood. Consistent with a presumed
environmental effect, the children of high attitude Peruvians who grow up in
low lands don’t develop larger chests. Peruvian who were born at sea level but
grew at up at high attitude developed the same amount of being capacity as
people who spent their entire lives at high attitudes (Ember & Ember, 2008).
Thereby larger chests among Andeans which was considered to be a genetic
adaptation, infact, presents acclimatisation which develops early in childhood
and persists for the lifetime of an individual. The Spitians who inhabit high
altitudes in the North West Himalayas showed large chest size in relation to
stature indicating developmental adaptation to low oxygen pressure of high
altitude (Singh et al. 1986). The larger chest circumference of the Bods of Ladakh
as compared to lowland Indians also suggests a structural response to the greater
lung function capacity and adaptation to high altitude hypoxia (Kapoor & Kapoor,
2005; Bhasin et al. 2008;). Rajis, a hunter-gatherer tribal population of Uttaranchal
showed lower chest circumferences comparable to the mid-altitude population
but lung functions comparable to those of other high-altitude populations. This
leads to the conclusion that indigenous high-altitude populations may possess
different genetic potential for thorax growth compared to low-altitude populations,
possible related to ethnic differences in the rate of growth of thorax related to
stature at high (Kapoor et al., 2009).
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Introduction to
Environmental
Anthropology
Altitude
Cultural adaptation
Acclimatisation to high altitude also concerns with the utilisation of glucose, a
critical O2
efficient source of energy for brain. There is an apparent dependency
on blood glucose under both resting and exercise conditions and increases with
the length of exposure to high altitude.
3.6 SUMMARY
As non- human primates are our closest living relatives, the identification of
underlying factors related to social behaviour, communication, infant care,
reproductive behaviour and so on aid in developing a better understanding of the
natural forces that have shaped so many aspects of human behaviour (Jurmain et
al, 2006). Since Homo sapiens evolved, populations have dispersed across the
planet, inhabiting niches that span the spectrum of available terrestrial habitats.
Many of these populations survived for millennia in extreme environments,
developing adaptations which have contributed significantly to the phenotypic
and to some extent genotypic variation found among present day people (James,
2010). So, in evaluating adaptations of ‘indigenous’ human populations living
in various extreme environments, the focus is really on how these populations
evolved so as to survive and reproduce under conditions that would seem to be
unfavourable (James, 2010). The study of many of these biological aspects of
humankind including adaptation and evolution could certainly be the purview of
human biologists. However, when such research also considers, the role of cultural
factors, it is placed within the discipline of Anthropology.
3.7 REFERENCES
Bhasin, M.K., Singh, L.P. and Kaur, B. 2008. “Biology of the People of Jammu
and Kashmir: The Growth Patterns and Physiological Variables of Various
Population Groups of the State”. Anthropologist , Vol. 10(2) : 89-118.
Ember, C. R., Ember, M. and Peregrine, P. N. 2008. Anthropology. Twelfth
edition, Pearson education.
Fedigan, L. M.1983. “Dominance and Reproductive Success in
Primates.”Yearbook of Physical Anthropology, Vol. (26): 91–129.
Fleagle, J.G. 1999. Primate Adaptation and Evolution. Second Edition, Academic
press: NY.
Frisancho, A. R. 1993. Human adaptation and accommodation. University of
Michigan Press.
Hanna, J.M. 1983. “Human heat tolerance: An anthropological perspective”.
Annual Review Anthropology, Vol. (12): 259-84.
Hanna & M Toel. 1985. “Human Heat Tolerance: An anthropological
perspective” Annual Review Anthropology, Vol. (12):259-84.
Henschel, A., HE Hanson. 1959. “Heat stress in desert environment”. Proc Am
Soc Mech Eng. Vol. (210): 1-4.
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Human Bio-cultural
Adaptations
James G.D. 2010. “Climate-Related Morphological Variation and Physiological
Adaptations in Homo sapiens”. In A Companion to Biological Anthropology
Edited by Clark Spencer Larsen. First edition. Blackwell Publishing Ltd. USA.
pp. 153-166.
Kapoor, S. and Kapoor, A. K. 2005. “Body structure and respiratory efficiency
among high altitude Himalayan populations”. Coll Antropol, Vol. 29 (1): 37-
43.
Kapoor, A.K., Tyagi, R. and Kapoor, S. 2009. “Nutritional status and cardiorespiratory
functions among adult Raji males, a hunter and gatherer tribe of the
Indian Himalayas”. Anthropological Science, Vol. 117(1): 1–7.
Little, M.A. and Hanna, J.M. “Cold response of high altitude population”. Int.
J. Biometeor, Vol. 21(2): 123-134.
Pusey, A., Williams, J., and Goodall, J. 1997. “The in?uence of dominance rank
on the reproductive success of female chimpanzees”. Science, Vol. 277: 828–
831.
Singh, S.P., Sidhu, L.S. and Malhotra, P. 1986. “Body morphology of high
altitude” Z. Morph. Anthrop, Vol. 72 (2):189-195. Scholander, P.F., V. Watters,
R. Hock & L. Irving. 1950. “Body insulation of some arctic and tropical mammals
and birds”. Bio Bull, Vol. (99): 225-36.
Stelzner, J. & K. Strier. 1981. “Hyena Predation on an Adult Male Baboon.”
Mammalia, Vol (45): 106–107.
Taylor, N.A.S. 2006. “Ethnic differences in thermoregulation: Genotypic versus
phenotypic heat adaptation”. Journal of Thermal Biology, Vol. 31(1–2): 90–
104.
Weiner, J.S. 1964. A note on acclimatisation and climatic differences: Their
bearing on racial differences. Expert meeting on biological aspects of race.
UNESCO. 1964.
Suggested Reading
Walter, H. 1971. “Remarks on Environmental Adaptation of man”. Human
Genetic, Vol. (13): 85-97.
Fleagle, J.G.1999. Primate Adaptation and Evolution. Second Edition, Academic
press.
Frisancho, A. R. 1993. Human Adaptation and Accommodation. University of
Michigan Press.
Jurmain, R., Lynn Kilgore & Wenda Trevathan. 2006. Essentials of Physical
Anthropology. Seventh Edition. Wadsworth, Cengage Learning: USA.
Relethford, J.H. 2002. The human species: An Introduction to Biological
Anthropology. The McGraw-Hill Companies: USA.
Swindler, D. R. 1998. An Introduction to the Primates. University of Washington
Press.
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Environmental
Anthropology
Sample Questions
1) Define adaptation and the bio-cultural strategies adopted by human for their
survival in cold climate.
2) Describe the influence of altitude environment on Human Physiology and
its consequences.
3) Elaborate the relation of Primate Ecology with their behaviour and social
structure.
4) Comment on ‘Human as biological continuum of primate’.
49
Human Bio-cultural UNIT 4 POTENTIAL ENVIRONMENTAL Adaptations
STRESSES
Contents
4.1 Introduction
4.2 Potential Environmental Stressors
4.2.1 Heat and Cold Stress
4.2.2 High Altitude Stress
4.2.3 Nutritional Stress
4.2.4 Infectious Disease
4.3 Summary
4.4 References
Suggested Reading
Sample Questions
Learning Objectives
At the end of this unit, you will be able to:
• understand about the potential environmental stressors that affects human
being;
• comprehend how human being by the process of their in-built biological
mechanism or by adopting some cultural practices make an effort to minimise
the effect of stress on their body; and
• know that the responses of human to these potential stressors are not the
same and there is variation in the response levels that exist in human
population.
4.1 INTRODUCTION
Human population inhabits almost all the parts of the world. Take for example
the Arctic dwellers like, Eskimos. These people are the original inhabitants of
the arctic regions. They have developed certain common adaptive features for
their survival in that environment. But, let us think of an individual or a group of
individuals who have migrated to the Arctic region from the tropical or temperate
region, what may happen to them? Since these tropical people do not have the
adaptive features like the Arctic dwellers, can they survive? The answer is yes.
This demonstrates the plasticity of human phenotypes in their capacity to adjust
to a wide range of environmental stress.
Human being has the capacity to endure various environmental stresses. Stressors
are conditions that threaten to disturb normal biological function or homeostasis.
Heat, cold, hypoxia, disease and malnutrition are some of the potential
environmental stressors that disturb homeostasis or increase the strain on human
being. The coping strategy of human beings with these environmental stressors
may be biological and/or cultural. Every individual with its own set of biological
potentiality tries to reduce strain or enhance the endurance of strain tolerance- a
&
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Anthropology
phenomenon defined as Acclimatisation. Although physiological and epidemiological
responses of individuals to a particular environment are representative of a species,
yet the concept that all population within a species would respond in the same
way was challenged. But remember that Adaptation and Acclimatisation cannot
be used synonymously. Adaptation is a genetically fixed condition of a species
or subspecies or of a specific group of organism, which favours survival in a
particular environment. In other words, adaptation is something which has genetic
endowment and the characters are transmitted generation after generation. On
the other hand acclimatisation is a temporary biological response to environmental
stress, and the response is withdrawn once the stress is removed.
4.2 POTENTIAL ENVIRONMENTAL STRESSORS
4.2.1 Heat and Cold Stress
Our body is divided into two parts (a) the core: inside which all the vital organs
are present and work and (b) the periphery or shell (or the extremities, like hands
and feet). The main heat reserve and production cite (because of metabolic
activities) of our body is the core. The core body temperature is 98.6° F (37° C).
But, this core body temperature varies between an acceptable range- 85°F or
29.4°C and 105°F or 40.6°C. However, the rise and fall of core body temperature
beyond this acceptable limit disturb the balance or homeostasis of the body. If
the core body temperature falls below 85°F or 29.4°C, an individual suffers
from hypothermia; and if it goes beyond 105°F or 40.6°C an individual suffers
from hyperthermia. The heat produced in the core is transmitted throughout the
body. On the other hand, the temperature of the periphery or shell is strongly
influenced by the environment and is not regulated within narrow limits like in
the core.
Heat transfer in the body Although heat is produced inside the body, it is lost
only through the tissues which are in contact with the external environment
(mostly through skin). Within the body, heat is transported by two meansconduction
through tissues and convection through blood. Heat flow by
conduction is proportional to the thermal conductivity of the tissues (like muscle
and adipose tissues), the change of temperature with distance in the direction of
heat flow and the area through which the heat flows. Heat flow by convection
depends on the rate of blood flow and the temperature difference between the
tissue and the blood supplying the tissue. Here, blood capillaries have a major
role to play. The blood capillaries have thin walls and together they form capillary
bed across a large surface area in various tissues. The heat is exchanged through
the thin walls of the capillaries between the tissues and blood.
When is the homeostasis of our body disturbed? During an endogenous heat
stress (or cold stress), when the ambient temperature remains below the skin
temperature, this heat flux may be enhanced by convective heat exchange between
circulatory blood and adjacent tissues with the circulatory blood carrying the
warmth from the central core to the peripheral tissues. During periods of
exogenous heat stress (or heat stress), when ambient temperature surpasses skin
temperature, the rate of sweating and the ability to move heat from the core to
the skin’s surface to facilitate evaporative heat loss. Both heat and cold stress
disturb the homeostasis of the body.
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Cold stress
Homo Sapiens is a species and thus its tolerance to cold stress is low. If you
carefully follow the record, you will observe that in India, the number of death
that takes place during cold season is higher than the hot season. A lesser extreme
condition that may develop out of cold stress is numbness and loss of mental
alertness.
When the ambient temperature falls much below the normal, the skin looses
heat (because of the development of thermal gradient). Under this condition, our
body tries to put a check to this heat loss by restricting the flow of blood to the
skin. This physiological response of the body to cold is called Vasoconstriction.
In this process the lumen of the blood vessels becomes narrow because of
contraction of muscular walls of the blood vessels, in response to the fall of
ambient temperature. The decrease in size of the lumen of the blood vessels
reduces the flow of the blood to the skin and hence, heat loss from the body is
reduced. However, prolonged absence of blood flow to the skin may affect energy
and oxygen supply to the tissues and may contribute to the etiology of cold
injury and in extreme situation may lead to frost bite. Here, another physiological
response to that is cold, ‘Cold induced vasodilation’ (CIVD) modulates the effect
of vasoconstriction. The response is termed as ‘hunting reaction’ or ‘Lewis wave’.
Let me give an example. If we put our finger tips in cold water we get a chilling
sensation for some time and later numbness develops that region because of
vasoconstriction. After some time, we regain sense in the fingers because of the
effect of CIVD. This suggests that a periodic oscillation of skin temperature
follows the initial decline in skin temperature during prolonged cold exposure.
But, the time interval of this periodic switching over from vasoconstriction to
vasodilation varies widely. For example, people who are habitual to this situation
(workers of ice factory or cold water fisher men) experience a less time interval
as compared to those who are not exposed to this situation regularly.
Activity
Take some ice cubes in a container and dip your fingers in it. Initially you
will feel a chilling sensation; this chilling sensation will subside after
sometime and your fingers will become numb. Gradually, you will regain
sense in your fingers.
Shivering thermogenesis is another way by which human population responds
to cold stress. Shivering is an involuntary pattern of repetitive, rhythmic muscle
contractions. This is often referred as a ‘Quasiexercising’ state, since the muscles
contract but do no external work. Shivering increases whole body oxygen uptake
(VO2) and thereby increasing the cardiac output. Since shivering is a muscular
activity, metabolic activity increases and thereby more energy produced.
The tolerance level to cold depends on various factors- individual’s familiarity
with cold exposure, age, physical fitness, type of body armour, intensity of wind
speed and duration of exposure. A lean individual, having a larger surface area to
body mass is more likely to suffer from cold stress since heat loss from the body
surface will be of higher degree. Young adult will be more tolerant to cold because
of their ability to generate adequate heat through physical activity. Again, adult
women, generally having shorter extremities and greater body weight compared
to men are more tolerant to cold stress. Greater body mass to body surface area
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means more heat production and greater average subcutaneous fat deposition
and thereby heat is restored. Wind speed expedites the heat loss from the body
and thereby reduces the heat tolerance.
Behavioural responses, such as taking shelter from the cold and wearing adequate
protective clothing, can greatly reduce the physiological strain of cold exposure
and obviate the need for nutritional interventions.
Heat stress
Similarly, during heat stress, i.e. when the external or ambient temperature
becomes higher than the peripheral or skin temperature, the heat load on the
individual rises. Extreme heat stress may lead to fatal heat stroke. In response to
this stress, the lumen of the blood vessel becomes wider n in order to allow more
blood to flow through it (cardiac output increases) and thus more heat is released
from the core to the environment via the shell or periphery. This physiological
response is called Vasodilation. Since vasodilation increases the pressure of the
blood down the vessels, cardiovascular strain also increases.
If the heat load still remains high, sweating through eccrine glands begins which
releases further heat from the body. Evaporation of 1 liter of sweat takes away
580 kcal of heat and humans can sweat up to 4 liters an hour at the extreme. But
the rate of sweating depends on the number of sweat glands that are active.
Studies show that people who live in high heat load regions have more number
of active sweat glands than their counter parts in cold regions. However, sweating
doesn’t remain as an effective cooling mechanism if the water vapour content in
the atmosphere is high.
The response to heat stress is not uniform. For example, if a person who is a
native dweller of cold climatic region visits Delhi during summer, the discomfort
level of that individual will be high. The person will sweat profusely, experience
cardiovascular strain (because of high level of vasodilatation) and may decide to
stay inside the room and take rest. Contrary to this, an individual who is a habitual
dweller of Delhi, will not face this discomfort level in a similar situation. Again,
all the people who are habitual dwellers of Delhi, will not respond similarly
because of their differential plasticity levels. Moreover, an individual who gets
the first exposure of heat load in the day will find a high level of discomfort level
but, will gradually feel stable as time passes.
Activity
If you start for your office from your home on a day in the hot summer
season, for the first 5-10 minutes you will sweat profusely, experience
tremendous heat load and cardiovascular strain. However, after some time
this discomforts will go, sweating rate will be reduced and cardiovascular
strain minimised.
The morphological factors impacting on thermal regulation in humans vary
substantially across the population. The impact of these morphological factors
becomes more pronounced when one examines the divergent subsets within a
population. Individuals differing in body size and composition appear to respond
differentially to variations in both ambient and core temperatures. Weight of an
individual has a significantly positive relationship with sweat loss. The size of
the skin surface also contributes positively towards effective cooling. If an
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individual has a larger skin surface compared to mass, then the tolerance level of
that individual will be high. A large skin surface means a wider surface area
through which heat is released by the process of vasodilation and sweating.
Apart from biological responses, people also adopt certain behavioural adjustment
and cultural practices to cope with heat stress. These include their clothing types,
structure of houses, building materials used to construct houses, time of activity
and food habits.
4.2.2 High Altitude Stress
High altitude environment is signified by decrease in air pressure, decrease in
water vapour pressure and increase in radiant energy penetration. Out of these
three, decrease in air pressure is crucial for human population. Now let us try to
understand with an example how the air pressure decreases with the increase in
altitude. Pile up books one above the other. Place your palm below the topmost
book and observe the pressure you are experiencing. Similarly place your palm
below the last book from the top and experience the pressure. I am sure that the
pressures will not be the same; the pressure in the latter case will be higher.
Similarly, air in the atmosphere appears to be like layers. Thus, at the sea level
the pressure of the air will be the highest and will gradually decrease as you
move above the sea level (towards higher altitude). The decrease in air pressure
at high altitude also signifies a decrease in oxygen pressure, since oxygen is a
component in the air. Breathing is a mechanical process. In this process we
voluntarily (subconsciously) develop a low pressure inside the chest cavity by
expanding the chest. In the way a pressure gradient develops between the
atmosphere (high pressure) and the chest cavity (low pressure) and air gushes
inside the lung. Now, if the air pressure in the atmosphere remains low, less
amount of air can enter inside the lung and thereby a less intake of oxygen. This
phenomenon is called Hypoxia. We all know that the red blood corpuscles (RBC)
of our body contain haemoglobin, which binds the oxygen that enters with the
air inside the lung. At sea level, the oxygen content of the inhaled air is high and
haemoglobin becomes 97% saturated with oxygen. But, with increase in altitude
level (around 4000m above the sea level), the oxygen pressure decreases and so
also the saturation level of the haemoglobin decreases.
An individual freshly exposed to high altitude will experience a low level of
oxygen intake, and will response to this stress by increasing the breathing and
heart beat rates in order to maintain comfortable supply of oxygen to the body.
This condition leads to certain health problems to the new comers of high altitude
like, fatigue, nausea, increase in breathing and heart beat rates, difficulty in sleep,
a reduction in aerobic capacity. It has been found that their aerobic capacity is
lost by 20-30 per cent compared to their capacity at sea level. However, aerobic
capacity is restored once they return to their native place (low altitude). The
natives of high altitude probably manage to cope with this stress by increasing
the count of their RBC, which in turn increases the oxygen saturation level of
haemoglobin. But, their work capacity is not improved if they (native high altitude
dwellers) go down to low altitude.
4.2.3 Nutritional Stress
Nutritional stress occurs when people fail to fulfill their nutritional requirement.
This may be caused by (i) non availability of particular nutrient(s) in an ecological
setup and (ii) unbalanced energy flow.
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i) The study of diet and nutrition has been a central component of much research
in human biology because it represents a critical interface between biology,
culture and the environment. It has been argued that the increasing ability
of our species to control and utilise energy was the key to understanding
cultural development over the history and prehistory of cultural change.
Patterns of nutritional and metabolic variation among human populations
provide additional insight into the influence of environmental and cultural
factors on evolution of nutrition in our species. It was commonly thought
that our early ancestors were heavily dependent on meat diet. The variety in
stone tool types and the depiction made by prehistoric human being in the
form of cave art can be cited as supportive evidence behind this perception.
In evolutionary framework, if one goes with this perception, then it becomes
difficult to exemplify why the structure of digestive system of modern human
signifies the requirement of some other nutrient for our body. A comparative
analysis of dietary practices between two contemporary human groups, the
Inuits (who are solely hunters) and Kung San (who are hunters and gatherers)
will help you to understand this thesis. Inuit diet is largely dependent on
meat or other animal body parts (like liver), since their habitat (arctic region)
is not conducive for faunal resource. On the other hand, the! Kung San
group lives in the jungles of South Africa, with plant and animal dietary
resources in abundance. Their dietary practice is more dependent on
diversified plant products, rather than meat. It has been observed that the
Inuits probably have a lower life expectancy and face more problems related
to mastication compared to their South African counterpart because of
excessive dependence on meat diet.
We all know that carbohydrate, protein and fat are the major sources of
nutrients in our body. Apart from these, vitamins and mineral salts also act
as nutrients for our body. Carbohydrate is the principal source of energy for
our body. Although fat produces more energy than carbohydrate, yet it is
less consumed by the people compared to carbohydrate because of difficulty
in digestion. However, there are regions in the earth, like the aArctic, where
people consume animal fat more than carbohydrate for energy because of
the easy availability of the former. Again, if we look at some Polynesian
communities, we will see that fat is the major source of energy and it is
derived from coconut. This demonstrates that people derive their nutrients
for their body from the available sources in that ecology. Protein is an
important nutrient and is essential for formation of all amino acids present
in our body. Human population, being omnivorous, derives this nutrient
both from animal and/or plant products. But, there are people who do not
consume animal products because of cultural proscriptions or dislike. Thus,
these people are totally dependent on plants to obtain protein. It has been
found that plants cannot supply variety of amino acids, like the animal
products. An inappropriate intake of these three nutrients causes certain
disorders among the human population. Kwashiorkor and marasmus are
two advanced forms of protein-calorie malnutrition. They are not two
different diseases with different dietary aetiology but two facets of the same
disease. It is suggested that marasmus, characterised by severe growth
retardation but remarkably well-preserved metabolic processes, represents
a state of good adaptation to the stress of protein-calorie malnutrition. The
response of the adrenal cortex may be crucial for this adaptation, a normal
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increase in plasma-cortisol helping in adequate mobilisation of muscle
protein and in maintenance of metabolic integrity. The failure of the adrenal
cortex to respond adequately may represent the crucial step in breakdown
of adaptation, resulting in the characteristic biochemical and clinical picture
of kwashiorkor. The representation of this nutritional disorder comes from
the countries like India, Africa, South East Asia, Caribbean and Mexico.
The common symptoms of this disorder are: changes in skin pigmentation,
decreased muscle mass, fatigue, large belly that sticks out and swelling.
Let me give some examples of other nutritional stress experienced by the
people of the world. (a) Water is a nutrient which acts as a medium of
transport and regulates the concentration of urine. In hot humid climate,
water is used up in the form of sweating as a mechanism of releasing body
heat. Again, in desert areas shortage of water in the environment leads to
fewer intakes. In both the situation, insufficient retention of water in the
body increases the chance of calculi (kidney stone formation). (b) Our body
has a high level of salinity and this is critical for many physiological
functions. People living in hot and humid climate lose a good amount of
salt from their body in the form of sweat. This loss of salt is supplemented
through selective dietary practices (plant and animal products). Human
beings probably have developed this practice in course of evolution, owing
to their origin in tropical regions of the world; may be by increased
dependency on meat diet, which is a good source of salt. (c) There are peoples
in this world (highland South Americans and Mesoamerican Indians) who
lack calcium in their diets. They supplement this deficiency by using burnt
limestone as spice in child’s food; the adults mix this burnt limestone with
coca leaves and chew. The staple food of Mesoamerican Indians is maize.
These people prepare maize by soaking it in lime water. This enhances their
calcium content of the body. (d) There are communities who consume leafy
vegetables, meat and iron rich organs of animals (heart and spleen) to
supplement iron deficiency. Use of iron cooking pots, as practiced in rural
India and some parts of Africa helps to remove iron deficiency in the body.
Again, over dependence of diet on meat and other blood rich organs (as
found among the Inuits) or continuous use of iron cooking pots might lead
to liver problems. (e) The importance of vitamins as a nutrient and its
supplementation through specific diets was understood during the first half
of the twentieth century. For example, people who take polished rice are
likely to be affected with thiamin deficiency as the rice husk contains thiamin.
Raw fish contains antithiamine compound called thiamase. Thus, the practice
of consuming raw fish (as practiced by coastal Japanese people) may lead
to thiamine deficiency. However, cooking of fish put an end to the action of
antithiamine substance and improves thiamine absorption.
ii) The energy requirement of our body varies with body size, levels of physical
activity and age. The minimum energy required by an individual when totally
inactive and in thermally neutral condition is called basal or resting
metabolism. Basal metabolism varies with other factors held constant
according to body size. Living in extreme climatic conditions generates
energy requirements. For example, living in hot climate leads to additional
requirement of energy, since high amount of heat loss takes place through
sweating and physical activity. Body size is another factor which varies
with energy requirements. A large body size requires greater energy. Some
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countries have their own energy requirement recommendations, specific to
body size. We perform various physical activities in our daily life. Some of
these activity types may be categorized as ‘heavy’, ‘medium’ and ‘light’.
Again, the duration of these activities also differ. For example, the energy
requirement of a person who is tailor by profession and the one who works
as an agricultural labour will not be the same. It has been found that a fit
young adult of 70 kg weight can spend four times more energy than its basal
metabolism for a period of 8 hours; but, the result for aged people and
children will be different from this estimate.
4.2.4 Infectious Disease
Infectious diseases are also called as communicable disease and are spread from
one individual to another through some pathogens. Pathogens are organisms
that cause infectious disease like, malaria, diarrhoea, AIDS, tuberculosis and
chicken pox. Pathogens may be micro (bacteria, protozoa, and virus) or macro
(helminthes) in nature. The time period between infection and development of
symptoms is called incubation period and it varies with the infection type of the
pathogen. The length of time between infection and the ability to infect somebody
else is called latent period.
Infectious diseases are a major cause of human mortality especially for the tropical
countries. In fact, the tropical environment is conducive for the growth and
survival of pathogens. The reasons are as follows: tropical region has a hot and
humid climate; it offers tremendous floral and faunal biodiversity and has high
human population density. Human beings are essentially warmth loving, and if
you look at the evolutionary discourse, you will find their distribution mostly in
the tropical regions, rather than in the temperate. The two most populous
continents of the world that come under this region are Asia and Africa. High
population density of these two regions leads to the spatial expansion of human
settlement and thereby more exploitation of natural resources. For example, large
scale denudation of forest took place at the cost of secured food supply and
expansion of human base started with the introduction of agriculture in the society.
This affected the biodiversity of this region. The pathogens that used to survive
on the nutrients of plants and animals are quickly shifting their hosts and finding
human as substitute. In this way many diseases which were once believed to
have affected non-humans are now becoming human specific. The unicellular
pathogens, with their simple cell structure, ability to modify their genotypes and
multiply fast are quickly adapting in the body of the new host (human). In the
process, human beings are becoming victims to emerging diseases (resulting
from new mutations) and are causing more severe stress, compared to the existing
ones. With the development of technology, people from the old world started
moving to the new world, i.e. North and South America and the Pacific islands.
In this way, the aborigines of the new world became victims to some new types
of infectious diseases (like small pox, measles and influenza) that are typical of
the old world. One may find this to be one of the reasons of dwindling number of
aborigines from the new world.
There are two kinds of immune responses to infectious diseases- antibody
mediated and cell mediated. Antibodies are proteins (also called immunoglobulin)
that appear in serum following exposure to antigen (foreign substance). Repeated
exposure to the same antigen elevates the immune response or the level of that
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antigen-specific antibody. The second kind of immune response is cell-mediated.
If a foreign body enters a cell, the infected cell is destroyed by special killer cells
like, lymphocyte and neutrophil through cell mediated immunity. However,
human immune system exhibits a complex set of responses to infectious agents
that varies with differential biological plasticity. As a result, some of us are more
susceptible to certain infections than others. Again, within human population,
stress caused by a particular infectious disease is not uniform. Communities that
get frequently exposed to a disease or have a historical episode of exposure to a
disease are likely to develop an immune system in their body. This immunological
adaptation causes less stress to its members than the ones who are newly exposed.
Travellers are recommended to protect from illnesses present in other parts of
the world and to prevent the importation of infectious diseases across international
borders. Which vaccinations you need depends on a number of factors including
your destination, whether you will be spending time in rural areas, the season of
the year you are traveling, your age, health status, and previous immunisations.
For example, there are some recommended vaccines for travel to India. One
such is anti-malarial vaccine. The Indians do not administer this vaccine, since
the disease is endemic.
An interacting complex between disease, vectors and its hosts should work
together for their co-evolution. For example, a disease can be considered as fit
(fit in the sense of the survival of the pathogen in the population), when (a)
causes less disturbance for host and vector, (b) survives on multiple host and (c)
gets adequate replacement of hosts. Pathogenic organisms use various strategies,
called modes of transmission, to spread from one host to another. The wide
variety of pathogens, vectors and transmission modes involved and the creative
intelligence of humans have all contributed to the incredible diversity of strategies
humans and other pathogens have evolved in order to survive. Modes of
transmission can broadly be divided into two types- direct and indirect. The
transmission of causal organisms for measles, influenza, HIV and so on takes
place directly from the body of an infected person to another by various means
like, sexual or simple body contact, through respiratory and fecal-oral
transmission. In case of diseases like malaria, plague and dengue fever, the causal
organisms are transmitted via intermediate hosts. Diseases like cholera, hepatitis
B and hook worm spread through any medium, may be soil/water/food. If you
take a close look at the different modes of transmission of these diseases, you
will find that human behaviour and activities like, high population density,
unhygienic sanitation and toilet practices, food habit, migration, agricultural
practices and construction of dams for irrigation and other purposes are
significantly responsible for the growth of pathogens and vectors and transmission
of diseases. Let me present few examples. (1) The causal organism(s) of diseases
like, measles, mumps and influenza, are found in the droplet of moisture released
from the body of an infected person. Thus, the chance of rapid spread of this
disease is high among the dwellers of slum and squatter and some areas of old
cities, owing to their close living situation. (2) The causal organism(s) of some
gastrointestinal illness (like worm infestation) are spread through fecal-oral
transmission. The infectious agents get excreted in feces of affected humans and
other animals. The susceptible humans come into direct contact with feces and
inadvertently introduce the infectious organisms into their mouths and in turn
cause illness.
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4.3 SUMMARY
Let us sum-up about what we learned in this module. We started our discussion
with heat and cold stress. Here we learned the various ways by which our body
maintains the heat balance between core and periphery. We further learned how
our body morphology is important in maintaining heat balance. Hypoxia is the
major stress related to high altitude, and people respond differentially to this
situation. Nutrition related stress is experienced by people all over the world.
This type of stress may occur because of the non-availability of macro or micro
nutrients in the ecology or unbalanced energy flow. It is interesting to learn how
different groups cope with these various types of nutritional stress with their
cultural practices. Human activities and in-activities are responsible for the spread
of infectious diseases in human population. But the differential immunological
response in human body makes some people more susceptible to infectious
diseases than others.
Thus, we learnt about some environmental stress and how these stresses disturb
homeostasis. We also learned how human population with their biological
plasticity and also by adoption of some cultural practices tries to minimise these
environmental stresses or increases their strain tolerance. It is also evident from
this discourse that the responses of human to these potential stressors are not the
same; there exist intra and inter group variations in response levels. In
Anthropology, it is important to studying the variation in the response levels to
different environmental stressors.
4.4 REFERENCES
Frisancho, A. R. 1993. Human Adaptation and Accommodation. Ann Arbor:
University of Michigan Press.
Harrison, G.A., Tanner, J.M., Pilbeam, D.R. and Baker, P.T. (Eds.). 1990. Human
Biology: An Introduction to Human Evolution, Variation, Growth and
Adaptability. Oxford University Press.
Jackson, F.L.C. 2000. Human Adaptations to Infectious Diseases. In: S Stinson,
B Bogin, R Huss-Ashmore and D O’Rourke (eds.) Human Biology: An
Evolutionary and Biocultural Perspective, New York: Wiley-Liss, 273-294.
Molnar, S. 1998. Human Variation: Races, Types and Ethnic Groups. (Chapter:
The adaptive significance of Human Variation, pp. 148-155.
Muehlenbein, M. 2010. Human Evolutionary Biology. Cambridge University
Press.
Sattenspiel, L. 2000. The Epidemiology of Human Diseases. In: S Stinson, B
Bogin, R Huss-Ashmore and D O’Rourke (eds.) Human Biology: An Evolutionary
and Biocultural Perspective, New York: Wiley-Liss, 225-272.
Stinson, S., Bogin, B., Huss-Ashmore, R and Rourke, D. O. (eds.) 2000. Human
Biology: An Evolutionary and Biocultural Perspective. New York: Wiley-Liss.
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Suggested Reading
Anderson, G.S.1999. Human morphology and temperature regulation.
International Journal of Biometerology, 43: 99-109.
Daanen, H.A.M. 2003. Finger cold-induced vasodilation: a review. European
Journal of Applied Psychology, 89: 411-426.
Moore, L.G., Neirmeyer, S. and Zamudio, S. 1998. Human adaptation to high
altitude: Regional and life-cycle perspectives. Yearbook of Physical Anthropology,
41: 25-64.
Sattenspiel, L. 2000. Tropical environments, human activities, and the transition
of infectious diseases. Yearbook of Physical Anthropology, 43:3-31.
Young, A.J., Sawka, N.S. and Pandolf, K.B. 1996. Physiology of cold exposure.
In: Nutritional Needs in Cold and High Altitude Environments. Washington DC:
National Academy Press, 127-147.
Young, A.J.1988. Human adaptation to cold. In: K.B. Pandolf, M.N. Sawka and
R.G.Gonzalez (eds.) Human Performance Psychology and Environmental
Medicine at Terrestrial Extremes. Benchmark Press Inc.: Indiananpolis, 401-
434.
Sample Questions
1) What is homeostasis?
2) What is hypoxia?
3) What are the ways by which human responses to cold stress?
4) How heat is transferred in our body?
5) Why tropical environment is conducive for the spread of infectious diseases?
6) When an infectious disease breaks, why the effect is not uniform in human
population?
7) What do you understand by co-evolution of disease and host?