Introduction to Introduction to EcologyEcology

[BIO 3510][BIO 3510]

Greek originOIKOS = householdLOGOS = study of…

Study of the “house/environment” in which we live.

Origin of the word “ecology”

Definitionsthe study of relationships of organisms to their

environment and to one another. a branch of science describing, explaining and

predicting where organisms live (distribution and abundance).

literally means the study of ‘houses’, ‘home conditions’, ‘habitats or more broadly ‘environment’ of plants and animals.

according to Crebs (1972), “Ecology is the scientific study of the interactions that determine the distribution and abundance of organisms”

systems are dynamic, not static.

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What is Ecology?What is Ecology?The The study of interactionsstudy of interactions that take that take

place place between organisms and their between organisms and their environmentenvironment..

It It explainsexplains how living organisms how living organisms affectaffect each other and the world they each other and the world they live in.live in.

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Habitat & NicheHabitat & Niche

HabitatHabitat is the is the place a place a plant or animal livesplant or animal lives

NicheNiche is an organism’s is an organism’s total way of lifetotal way of life

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History of EcologyIn 1859, a French Zoologist St. Hilaire, had

employed the word ‘ethology’ for the study of organisms in relation to their environment.

The term ‘ecology’ was first defined by a German biologist Ernst Haeckel in 1866.

The term ‘ecology’ is derived from the Greek word ‘Oikos-meaning ‘house or dwelling place and ‘logos’ meaning discourse.

Ecology - A Science for Today!We have a great need for ecological

understanding:what are the best policies for managing our

environmental support systems -- our watersheds, agricultural lands, wetlands?

we must apply ecological principles to: solve or prevent environmental problems inform our economic, political, and social thought

and practice.

Ecology and Environmentalism

Ecology is a science and is different from environmentalism.

Ecology provides the science behind many questions related to human impacts on the environment but it is not the same as environmentalism.

Environmentalism is an advocacy or concern for the environments.

However, most ecologists would tend to support efforts to protect natural systems and restore degraded environments

Scopes of Ecology:Interactions determine distribution and abundance of

organisms.Two main themes in ecology are:

Where do organisms live? & Why?How many organisms are present? & Why?

By understanding the principals of ecology we can then apply them to management of both plants and animals

By studying ecology, we expect to be carried through the sequence i.e. observation, explanation, hypothesis, experiment and conclusion where we are now on the path to understanding.

We are not only interested in the structure of the population or community but also how it functions. In other words, we are interested in “cause and effect”.

Divisions of Ecology:Divisions of Ecology

Autecology- ecological study of individual species

Synecology – ecological study of a population of a species growing together or communities.

How Ecologists Study the Natural World

Ecologists, like other scientists, employ a scientific method:observation and description of natural

phenomenadevelopment of hypotheses or explanationstesting the predictions of these hypotheses

We test hypotheses because many explanations are plausible (reasonable). Which is best?

Ecology Employs the Scientific Method

ObservationObservation

HypothesisHypothesis oror modelmodel

PredictionPrediction

ExperimentExperiment

DeductionDeductionDeductionDeduction

InductionInductionInductionInduction

1.Observing• What species live here?

• How many individuals of species are there? 2.Experimenting

• Used to test a hypothesis • Ex - making artificial environments in the

lab

3.Modeling • Making models to gain insight into complex

phenomena • Ex. - Global warming

What is an hypothesis?An hypothesis is an idea about how the

world works:e.g., “Frogs sing on warm nights after periods

of rain.”

We often wish to understand two components of such a phenomenon:how? (encompasses physiological processes)why? (encompasses costs and benefits of the

behavior to the individual)

Experiments test predictions.Hypotheses generate predictions:

if observations confirm the prediction, the hypothesis is strengthened

if observations fail to confirm the prediction, the hypothesis is weakened (or rejected)

Best tests of hypotheses are experiments:independently manipulate one/few variablesestablish appropriate controls.

Methods to Study EcologyTheoretical

Mathematical modelsLaboratory

Highly controlled but lack realismField

Highly realistic but may lack control.

Mathematical models are powerful tools:researcher portrays system as set of

equationsmodel is an hypothesis and yields

predictions that can be tested.examples include:

models of disease spread models of global carbon

Field Study