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3-1 What Is Ecology?

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• Interactions and Interdependence • Ecology - the study of interactions among organisms and

between organisms and their environment (surroundings).

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– Biosphere • portions of the planet in which all of life exists

– land – water – Air (atmosphere)

• extends from about 8 kilometers above Earth's surface • 11 kilometers below the surface of the ocean.

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– Interactions within the biosphere • between organisms and the environment in which they

live. • contributes to an ever-changing (dynamic) biosphere.

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• Levels of Organization

– range in complexity from a single individual to the entire biosphere.

– levels of organization include:

• individuals

• Populations

• Communities

• Ecosystems

• biomes.

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Ecosystem

Community

Population

Individual

Biome

Biosphere

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– Species • a group of organisms so similar to one another that they

can breed and produce fertile offspring.

– Populations • groups of individuals that belong to the same species and

live in the same area.

– Communities • groups of different populations that live together in a

defined area.

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– ecosystem • collection of all the organisms that live in a particular place • Living and nonliving, or physical, environment.

– Biome • A group of ecosystems that have the same climate and

similar dominant communities.

– Biosphere • The highest level of organization

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• Ecological Methods – three basic approaches:

• observing • experimenting • modeling

– rely on the scientific method

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– Observing • often the first step • Some are simple • Some are complex • may form the first step in designing experiments and

models.

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– Experimenting • can be used to test hypotheses. • may set up an artificial environment

– to imitate and manipulate conditions

• May be conducted within natural ecosystems.

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– Modeling • To gain insight into complex phenomena. • May consist of mathematical formulas

– based on data collected through observation and experimentation.

• predictions made by models – tested by further observations and experiments.

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END OF SECTION