Download Ecological Succession

Ecological Succession
7 October 2016
Bellwork
• Please pick up a CH 5 Vocab (Practice) Quiz
from the back table.
• Please be working silently and independently
on the practice quiz when the bell rings.
Agenda
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Bellwork
Go over IP
Finish Ch 5 Notes
Ch 4 Quiz
Keystone Species Poster presentations
IP: Ch 5 MC & FRQ
5-4: How do communities and ecosystems
respond to changing environmental conditions?
• Concept 5-4: The structure and species
composition of communities and ecosystems
change in response to changing environmental
conditions through a process called ecological
succession.
Ecological Succession
• The gradual change in species composition in
a given area during which some species
colonize an area and their populations
become more numerous, while populations of
other species decline and may even disappear.
– Colonizing (pioneer) species arrive first
Primary vs. Secondary Succession
• Primary succession: gradual establishment of
biotic communities in lifeless areas where
there is no soil in a terrestrial ecosystem or no
bottom sediment in an aquatic ecosystem.
• Secondary succession: a species of
communities or ecosystems with different
species develop in places containing soil or
bottom sediment.
Primary Succession
• Some ecosystems start from scratch.
• Begins with an essentially lifeless area.
– Bare rock exposed by glacier
– Newly cooled lava
– Abandoned highway or parking lot
Secondary Succession
• Ecosystem has been disturbed, removed, or
destroyed, but soil or bottom sediment
remains.
– Abandoned farm ground
– Burned or cut forests
– Heavily polluted streams
– Land that has been flooded
Succession doesn’t follow a
predictable path
• There is a general tendency for succession to
lead to a more complex, diverse, and
presumably stable ecosystem.
• However, ecosystems are ever changing.
• There is no “end point” for succession.