Transcript 4.3 Succession

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Review- What effects do organisms do pioneer
species have on an environment undergoing
primary succession
Explain- why do communities change over time
Apply Concepts- When a whale or other large
marine mammal dies and falls to the ocean floor,
different waves of decomposers and scavengers
feed off the carcass until nothing remains- do you
think this is an example of succession- explain
CH 4 ECOSYSTEMS AND COMMUNITIES
4.3 Succession
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Krakatau exploded in 1883, leaving a tiny, barren
island.
2 years later grasses were growing
14 years later there were 49 plant species, along
with lizards, birds, bats, and insects
1929, a forest containing 300 plant species had
grown
How did the island ecosystem recover so quickly.
Ecological Succession
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Series of more-or-less predictable changes that
occur in a community over time
 Some
species move in and some die out
 Number of species typically increase.
Primary Succession
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Succession that begins with bare rock.
Primary Succession
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Pioneer Species
 First
species to colonize barren areas
 Lichen—mutualistic symbiosis between a fungus and
an alga- often the first life
 Fix atmospheric nitrogen, break down rock, and add
organic material to form soil.
Secondary Succession
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Succession that begins with some surviving species
and soil
Occurs faster than primary succession
Often follows natural or human disturbance.
Climax Communities
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Species in a stable, mature environment that won’t
change into a different community.
Natural Disturbances
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Secondary succession in healthy ecosystems after
natural disturbances often reproduces the original
climax community.
Human-Caused Disturbances
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Ecosystems may or may not recover from extensive
human disturbances.
Succession Lab
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Place a handful of dried plant material into a clean
jar
Fill the jar with boiled pond water and determine
the initial pH of the water
Cover the jar and place it in an area that receives
indirect light
Examine the jar every day for the next few days
When the water in the jar appears cloudy, prepare
microscope slides of water from various levels of
the jar using a pipette to collect the water
Look at the slides under the low powered objective
lens and record your observations
Succession Analyze and Conclude
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Infer- Why did you use boiled water
Infer- Where did the organisms you saw come
from
Draw Conclusions- Was ecological succession
occurring- give evidence to support your answer
Evaluate and Revise- Check you results against
those of you classmates- Do they agree, how do
you explain the differences