ECOLOGY

Ecology is: The study of the relationship between living organisms and their environment.

In other words—Ecology is the study of Ecosystems. An ecosystem is an interacting system of living organisms and their non-living environment.

An ecosystem is made up of two sets of factors: A) biotic factors—the living portion of the ecosystem. Living organisms such as plants, animals, fungi, and the list goes on.

The biotic factors in an ecosystem are grouped into two basic groupings: Populations: Groups of the same species of organism living in an area.

And Communities—all of the living organisms in an ecosystem.

B) Abiotic factors—the non-living portion of the ecosystem. This includes the following: Water Soil Temperature Sunlight

In order for an ecosystem to exist it must meet 3 criteria to be SELF-SUSTAINING: HAVE AN ENERGY SOURCE (SUN) ENERGY MUST BE CONVERTED OR STORED FOR USE BY ORGANISMS NUTRIENTS MUST BE RECYCLED

YOU DECIDE— ENVIRONMENT OR ECOSYSTEM?

ENVIRONMENT OR ECOSYSTEM?

ENERGY FLOW IN ECOSYSTEMS Food chains and webs show how eaters, the eaten, and the decomposed are connected to one another in an ecosystem. Figure 3-17

Food Webs Trophic levels are interconnected within a more complicated food web. Figure 3-18

Energy Flow in an Ecosystem: Losing Energy in Food Chains and Webs Ecological efficiency: percentage of useable energy transferred as biomass from one trophic level to the next. 10% rule- only 10% of energy moves up. Figure 3-19

Bioaccumulation—build up of toxins in the tissues of organisms through the food chain. Biomagnification—as toxins move up the food chain, they become more concentrated. The higher the organism is on the pyramid, the more toxins it builds up.