1. Ecosystems
Chapter 21

2. Definition
All of the living and nonliving elements in a particular place.
Living elements: incude plants, animals, and people
Nonliving elements; include sunlight, soil, air, water, and temperature.

3. Ecosystems Large and Small
The planet, the ocean, a forest
Small:
A puddle, a tree, a flower

4. Divisions within an Ecosystem
Organisms: found within populations
Ex: one rabbit
Community: groups of plants and animals adapted to similar conditions
Populations: found within communities
Ex: rabbits

5. Changes in Ecosystems Balanced ecosystems: Unbalanced ecosystem:
Population sizes of different species don’t change relative to each other
Unbalanced ecosystem:
A change in predator or prey population

6. Whole System Affected
A change in one feature can affect the whole system
Ex: forest fire, nonative species, deforestation
The good: ecosystems eventually return to original conditions

7. Short Term Changes Are easily reversed
Seasonal changes: birds migrating, trees lose leaves, animals hibernate

8. Long Term Changes Harder to reverse
Examples: volcanic activity, global warming, melting ice caps
How can these change ecosystems?

9. Changes by Human Activity
Growing crops, constructing roads and buildings, and building dams.
How can these affect ecosystems?

10. Nonnative Species Starlings, zebra mussels, dandelions
Organisms that are from another ecosystem
Compete with native species for food and shelter