Available at http://planet.uwc.ac.za/nisl/Eco_people/Presentations/

Ecology Primer: What is Ecology?

Nicklaus KrugerNISL

nicklaus@webmail.co.za

An Optional Graphiccan go here

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”

What is Ecology?What is Ecology?1,2,31,2,3

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)

Ecology: A bit about it allEcology: A bit about it all1,2,31,2,3

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 (non-living) interactions in an ecosystem

The Many Faces of EcologyThe Many Faces of Ecology2,3,42,3,4

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

The Many Faces of Ecology (cont)The Many Faces of Ecology (cont)1,41,4

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

Sciences associated with EcologySciences associated with Ecology1,41,4

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 HistoryNatural History1,3,4,51,3,4,5

Natural History: Some famous facesNatural History: Some famous faces

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

Ecology: Some important points1Ecology: Some important points1

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

Physical resources and limiting factorsPhysical resources and limiting factors11

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 Ecosystem ConceptThe Ecosystem Concept6,7,86,7,8

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

The BiosphereThe Biosphere99

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

BiomesBiomes

Biomes: A few examplesBiomes: A few examples

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 NicheEcological Niche10,11,1210,11,12

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)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

Ecological Niche (cont…)Ecological Niche (cont…)

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 117:893-922

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

ReferencesReferences