Succession and Change in Ecosystems

1
Succession and Change in Ecosystems

• Topic 6
• Science 7

2
Succession

• The gradual process by which some species replace
  other species in an ecosystem

3
Primary Succession

• The gradual growth of organisms in an area that
  was previously bare, such as rock.

4
Secondary Succession

• The gradual growth of organisms in an area that
  previously had a number of organisms. (ex. Burned
  forest)

5
Changes are caused by human activity

• Some species adapt better than others

6
Pest Control

• Sometimes when a pesticide like DDT is used to
  kill one species it ends up killing beneficial
  organisms living in the same environment.

7
Biological Control

• Using a pests natural enemy to control pests
• But BEWARE when introducing new species

8
Introduced Species

• Species brought to an environment where they are
  not naturally found.

Zebra mussels were introduced by accident to the
Great Lakes from ships. With no natural
predators their population exploded and they took
over the niche of naturally occurring species
(plus they clog pipes!)
9
Species in Danger

• Extinct organisms that no longer exist anywhere
  in the world
• Some causes
• Habitat loss
• Introduced species
• Pollution
• Changes in climate

10
Extirpated

• When a species no longer exists in a habitat it
  used to exist in.
• caribou

11
Endangered

• When a species is threatened with extinction