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Ecology Primer: What is Ecology?
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Nicklaus Kruger
NISL
[email protected]
Available at http://planet.uwc.ac.za/nisl/Eco_people/Presentations/
What is Ecology?1,2,3
 Ecology is the study of the interactions and interrelationships
between organisms and their environments
 The term “ecology” was coined by Ernst Haeckel in the nineteenth
century, from the Greek:
 Oikos, meaning “home”
 Logos, meaning “to study”
Ecology: A bit about it all1,2,3
 Organisms in different environments are exposed to different
stresses, and exhibit a variety of responses
 Ecologists are interested in individual organisms, but also in
patterns in nature beyond those embodied in organisms
 The diversity and complexity of biological communities
 Energy and nutrient flows
 The structure and function of ecosystems
 Ecologists are interested in individual organisms, but also in
patterns in nature beyond those embodied in organisms
 Human beings are a part of the natural world, having evolved to suit
our changing environments as other organisms did
 Recently, humans have acquired the ability to significantly alter our
environments (through the use of tools, from fire to automobiles)
The Many Faces of Ecology2,3,4
 Ecology is comprised of many sub-disciplines
 Autoecology deals with the individual organism in relation to its
environment
 Population ecology studies the dynamics of a single population in a
single species
 Community ecology examines the interactions among all the
populations of different species living in a specific area
 Ecosystem ecology is the study of the biotic (living) and abiotic (nonliving) interactions in an ecosystem
The Many Faces of Ecology (cont)1,4
 Other more specific and highly-specialized sub-disciplines of
modern ecology include:
 Physiological ecology: examines how the bodily processes of
an organism have adapted to its physical environment
 Genetic ecology: examines the ways in which genes affect
ecological processes, and vice versa
 Systems ecology: uses mathematical modeling to examine the
interactions among the many components of an ecosystem
 Landscape ecology: examines the spatial patterns associated
with ecological processes
Sciences associated with Ecology1,4
 Three fields of scientific study are particularly closely related to
ecology
 Natural history is the study of the habits, behaviour and interactions
of organisms in their natural environments
 Environmental science is the study of the ecological effects that
human activities have on the natural environment
 Conservation biology uses the principles of ecology to manage and
maintain biological diversity in both natural systems and systems
affected by human activity
Natural History1,3,4,5
 Long before there was a science of ecology or evolution, there was
natural history
 Through the ages, people have observed and documented
organisms and their interactions with the environment
 The chief difference between natural history and ecology is that
natural history is more of a descriptive study of natural phenomena,
while ecologists attempt to test hypotheses and answer specific
questions
Natural History: Some famous faces
Ecology: Some important points1
 The organism is the fundamental unit of ecology
 Organisms fall into natural groups called species
 The natural world can be conceived as a set of patterns
Physical resources and limiting factors1
 We have already defined ecology as the study of the interaction
between the biotic and abiotic environments
 Physical resources are abiotic factors that an organism requires for
survival
 Physical factors are abiotic parameters that define an area where a
particular organism may be able to prosper
 Limiting factors are factors that govern or control the presence of a
species within a certain area
The Ecosystem Concept6,7,8
 The ecosystem is an integral concept to ecology
 It can be defined as: any situation where there is interaction
between the biotic and abiotic environment
 This can apply to units of variable extent:
 Microecosystems
 Mesoecosystems
 Macroecosystems
The Biosphere9
 The outer layer of the Earth can be divided into three
compartments: the atmosphere, hydrosphere and lithosphere
 To this, ecologists normally add a fourth category: the biosphere
 The biosphere is usually defined as that porion of the Earth that is
inhabited by life
Biomes
 The biosphere is divided up into several different ecosystem types
 These are defined by climate
 the interaction of temperature and rainfall is particularly important
 Biomes vary in both biotic and abiotic make-up
Biomes: A few examples
Ecological Niche10,11,12
 The study of organisms at the community level is made more
difficult by the natures of communities themselves
 To deal with this difficulty, ecologists introduced the concept of the
ecological niche
 The niche concept expresses the relationship of the individual to all
aspects of its environment
 The term was originally introduced by Joseph Grinell, and
developed more fully by Charles Elton, and then George
Hutchinson
Ecological Niche (cont)
 Hutchnison defined the niche concept formally:
 The activity range of a species can be described along every
dimension of the environment, including biotic and abiotic factors
 Each of these dimensions can be thought of as a dimension in
space
 We cannot visualize n-dimensional space where more than three
dimensions are involved, but we can handle them mathematically
Ecological Niche (cont…)
 Niche overlap determines the degree to which species fulfill similar
roles in an ecosystem
 The more similar two species are, the greater the degree of competition
between them
 Within a species, all individuals are specialized to some degree with
respect to the population as a whole
References
1.
Krohne, D.T. (2001) General Ecology (2nd Ed.) Brooks/Cole, Pacific Grove
2.
Wikipedia contributors. Ecology [Internet]. Wikipedia, The Free Encyclopedia; 2006 Aug 26, 00:20 UTC
[cited 2006 Sep 1]. Available from:
http://en.wikipedia.org/w/index.php?title=Ecology&oldid=71913381.
3.
Weiner, J. (1995) On the practice of Ecology. The Journal of Ecology 83:153-158
4.
de Laplante, K. (2004) Toward a more expansive conception of ecological science. Biology and
Philosophy 19(2):263-281
5.
Downie, R. (1999 ) What is natural history, and what is its modern role? Glasgow Naturalist 23(4):1-6
6.
Golley F.B.: (1993) A History of the Ecosystem Concept in Ecology: More Than the Sum of the Parts,
Yale University Press, London.
7.
Wikipedia contributors. Ecosystem [Internet]. Wikipedia, The Free Encyclopedia; 2006 Aug 31, 12:39
UTC [cited 2006 Sep 1]. Available from:
http://en.wikipedia.org/w/index.php?title=Ecosystem&oldid=73013320.
8.
S.L. Pimm (1984)The complexity and stability of ecosystems. Nature 307:321 - 326
9.
Wikipedia contributors. Biosphere [Internet]. Wikipedia, The Free Encyclopedia; 2006 Aug 31, 23:53
UTC [cited 2006 Sep 1]. Available from:
http://en.wikipedia.org/w/index.php?title=Biosphere&oldid=73126352.
10. Patten, B.C. and G.T. Auble (1981) System theory of the ecological niche. American Naturalist 117:893922
11. G.E. Hutchinson (1959) Homage to Santa Rosalia, or Why are there so many kinds of animals? The
American Naturalist 870:145-159
12. Colwell, R.K. and D.J. Futuyma (1971) On the measurement of niche breadth and overlap. Ecology
52:567-576