1. KEY CONCEPT Every ecosystem includes both living and nonliving factors.

2. An ecosystem includes both biotic and abiotic factors.
Biotic factors are living things.
plants
animals
fungi
bacteria
plants

3. Abiotic factors are nonliving things. moisture temperature wind
sunlight
soil
moisture
sunlight

4. Changing one factor in an ecosystem can affect many other factors.
Biodiversity is the assortment, or variety, of living things in an ecosystem.
Rain forests have more biodiversity than other locations in the world, but are threatened by human activities.

5. A keystone species is a species that has an unusually large effect on its ecosystem.

6. Keystone species form and maintain a complex web of life.
creation of
wetland
ecosystem
increased waterfowl
Population
increased fish
population
nesting sites for birds
keystone species

7. Which of the following is an example of a biotic factor in an ecosystem?
Sunlight
Stream
Tree
Rock

8. Wind is considered to be an abiotic factor because it
Is not related to biodiversity
Is a nonliving thing
Is in equilibrium
Is not in any ecosystem

9. A rainforest has a high level of biodiversity because it has
Many abiotic factors
Some endangered species
Few connections between living things
A wide variety of living things

10. A keystone species is a species that
Goes unnoticed if its numbers decrease
Alters an area by building bridges and dams
Leads to a decrease in an area’s biodiversity
Has an unusually large impact on its ecosystem.

11. Beavers are sometimes trapped for their fur
Beavers are sometimes trapped for their fur. What could be one effect of increased trapping of beavers in an area?
Biodiversity among the area’s fish would increase
The number of herons and kingfishers would decrease
There would be more nesting areas for waterfowl
More trees would be cut down