1. CHAPTER 5 HOW ECOSYSTEMS WORK

2. Chapter 5 - section 3 How Ecosystems Change
ECOSYSTEMS ARE CONSTANTLY CHANGING!!!

3. * the process may take hundreds or thousands of years
Ecological Succession - a regular pattern of changes in a community that occur over time
* the process may take hundreds or thousands of years

4. ECOLOGICAL SUCCESSION occurs when 1
ECOLOGICAL SUCCESSION occurs when 1. a new land area is exposed or when 2. an existing land area is disturbed

5. Primary Succession occurs on new land areas or where no soil exists
What are some examples of primary succession?

6. occurs when an existing community had been disturbed
Secondary Succession
occurs when an existing community had been disturbed
What are some examples of secondary succession?
due to humans or natural causes ?

7. How are fires a necessary part of secondary succession?
Some trees only release seeds after exposure to the intense heat of a fire
Minor fires remove brush and dead wood that accumulates
Some animals depend on vegetation that sprout s after a fire has cleared the land

8. FIRES IN YELLOWSTONE
Since 1972 National Park Service policy on fires has been to …..
- allows fires caused by lightning to burn unless they threaten lives, property or unique scenic areas
- put out all human-caused fires
Fires of 1988 – conditions were unusual
little rain during the summer
summer turned out to be driest on record
the previous winters were dry

9. 1988

11. 1988

12. 1988

13. 2010 – 22 years later

14. 2010 – 22 years later

15. Primary or Secondary Succession?

16. Primary or Secondary Succession?

17. Primary or Secondary Succession?

18. Primary or Secondary Succession?

19. Primary or Secondary Succession?

20. Primary or Secondary Succession?

21. Primary or Secondary Succession?

22. the first species to inhabit an area
Pioneer Species –
the first species to inhabit an area
Pioneer Community – the first community of living things to inhabit an area
Lichens
Mosses
Small Plants

23. LICHEN
What is a lichen?
a mutualistic relationship between a fungus and alga
Alga – produces food (by photosynthesis)
Fungi – absorbs nutrients from rocks and makes the environment hospitable for the alga
Why are lichens important?
the action of lichens begins to break down rock which begins the formation of soil so that succession can occur

30. Succession CULMINATES when…
a final, stable community is established –
the final community is called a CLIMAX COMMUNITY
climax community in
Baja, California
is a DESERT

31. SERAL COMMUNITY = a transitional community or communities that occur before a climax community is established
PIONEER COMMUNTIY to SERAL COMMUNITY(IES) to CLIMAX COMMUNITY

32. What would be the climax community in the eastern US?
Deciduous Forest

33. What do you think old-field succession is?