Transcript ecological succession

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
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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=pla
yer_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