Our Environment

Lesson

Part 1 — how living things and their surroundings work together in an ecosystem, how food and energy pass along food chains, and why harmful chemicals build up in top predators.

In this lesson you will

Identify biotic and abiotic components of an ecosystem
Classify organisms as producers, consumers and decomposers
Construct food chains and food webs and name trophic levels
Apply the 10 percent law of energy transfer
Explain biological magnification of pesticides

Concept

What is an ecosystem?

An ecosystem consists of all the interacting organisms in an area together with the non-living constituents of the environment.

Table: natural ecosystems include forests, ponds, lakes, grasslands and seas; artificial, human-made ecosystems include gardens, crop fields and aquariums
Type	Examples
Natural ecosystems	Forest, pond, lake, grassland, sea
Artificial (human-made) ecosystems	Garden, crop field, aquarium

Diagram

A pond ecosystem

Producers, consumers and decomposers share the pond with its water, mud, light and air.

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