ECOLOGICAL SUCCESSION Obj: 11D Describe how events and processes that occur during ecological succession can change populations and species diversity.

What is ecological succession? orderly process of change in an ecosystem brought about by the progressive replacement of one community by another until a stable climax is established

What differences do you see in these pictures?

What disasters could affect the plant population? Tornados Hurricanes Forest fires Volcanoes Floods

Climax Community The ideal end community in any given ecosystem https://www.youtube.com/watch?v=iZA5yfrzLV8&feature=player_embedded

Primary Succession Occurs on bare rock or hardened lava on which no soil organisms exist Begins with arrival of lichens, a pioneer species

Pioneer Species Able to grow on barren rock First organisms to grow during primary succession Ex: lichens, mosses

Secondary Succession Occurs after an event in which the ecosystem is damaged, but not destroyed. Because soil remains, secondary succession is faster than primary succession

On Hwy 31 going to Kilgore…

How long is the time?

https://www.youtube.com/watch?feature=player_embedded&v=4RsMyVavT2Q

Succession also in bodies of water

large deep lakes shallow ponds grassland

How does succession affect population size? Forest fire or volcanic eruption will decrease population and diversity If the soil is intact, over time, the populations will recover Ex: insects deposit eggs in the soil & these eggs can survive and hatch after a fire

How does succession affect population diversity? Animals that survived may move to other regions which reduced competition for other species Can lead to entirely new ecosystems if new herbivores move in where there were once none. Eventually carnivores will move in to eat new herbivores.

How do population and species diversity change as succession progresses? Population size and species diversity both increase during ecological succession Over time, more species are able to survive and become established

Smaller producers are replaced by larger ones, such as small trees and shrubs As insects increase, birds and other animals that eat insects arrive Eventually a climax community will build again