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

ECOLOGICAL SUCCESSIONObj: 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?

• Tornados• Hurricanes• Forest fires• Volcanoes• Floods

What disasters could affect the plant population?

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

• Beings 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

• 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 does succession affect population diversity?

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