1. Ecological Succession Notes

2. The environment is constantly changing as a result of weather or the activities of humans & other organisms.

4. These changes can naturally happen slowly over time or quickly as a result of natural disasters or catastrophic events.

5. A community of organisms that occupy an area is also constantly changing and result in long-term changes in an ecosystem.

6. All of these changes that occur in an ecosystem over time result in ecological succession.

7. Primary succession occurs in an area where no ecosystem existed.

8. Examples: after a volcanic eruption or bare rock under a glacier.

9. The first species to populate an area during primary succession, called pioneer species…

10. …are usually mosses or lichens which are able to grow on bare rock… release acids that begin to break down rock to create soil.

11. As colonies of grasses & ferns are established, small animals will move into the area that feed on the plants.

12. Larger animals can then move in & feed on the smaller animals.

13. More soil is formed that can support larger plants like shrubs which can provide new habitats for more animals.

14. More soil continues to form & become richer & deeper so that trees can now be supported & the community continues to grow.

15. Given enough time and the right conditions, primary succession may lead to a community in equilibrium that will not change drastically unless the ecosystem is disturbed.

16. This type of community is known as a climax or mature community.

17. Secondary succession occurs after a disturbance in an existing ecosystem where soil is already established so weeds and grasses can start to grow immediately.

18. Examples: after forest fires, tornadoes, hurricanes, floods, etc…

19. Secondary succession occurs more rapidly than primary succession to restore the ecosystem to a state of equilibrium that can be maintained over time.

20. Stages of primary succession: (forest) bare rock=> mosses / lichens => grasses & ferns=> bushes & shrubs=> trees (young forest) => mature forest (climax community)

21. Stages of primary succession
mosses & lichens
mature forest=> climax community
trees- young forest
bushes & shrubs
grasses & ferns
bare rock
Time

22. Stages of secondary succession: (forest) weeds=> grasses & ferns=> bushes & shrubs=> trees (young forest) => mature forest (climax community)

23. Stages of secondary succession
mature forest=> climax community
bushes & shrubs
trees- young forest
grasses & ferns
weeds
Time