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Today’s Topic Evolution: Succession - Verona Public Schools · 2015-06-13 · Today’s Topic...
Transcript of Today’s Topic Evolution: Succession - Verona Public Schools · 2015-06-13 · Today’s Topic...
Today’s Topic Evolution: Succession
Learning Goal:
SWBAT differentiate between primary and
secondary succession, and predict how a
community will return to a state of equilibrium.
Have a seat and take out your
notebooks.
I will pass out a study guide momentarily.
Homework
Complete the Simulating Adaptations Lab
(Three Days Late)
Complete cattle, cows, and dogs articles.
(Five Days Late)
Upcoming Test
Our next test will take place on
Friday, 4/17.
It will cover all of Evolution:
Biological Evolution
Natural Selection
Artificial Selection
Adaptations
Extinction
Succession
After the Disasters What percentage of life constitutes a
“mass-extinction event”?
What happened during the
Cretaceous-Paleogene extinction event?
How does the world
even begin to recover
after such a horrible
catastrophe?
After the Disasters The answer lies within Ecological
Succession.
Ecological succession refers to the
somewhat predictable series of changes over
time that a community will experience after a
disturbance.
CrashCourse Video To help introduce this idea, we are going
to watch a ten-minute episode of
CrashCourse.
Please pay attention to the following:
1. What historical error does the presenter
make?
2. The following terms: Disturbance, Ecological Succession,
Primary Succession, Pioneer Species,
Secondary Succession, Climax Community
What is a Disturbance? To set off the entire process of
succession, a destructive event needs to
a occur – or a disturbance.
A disturbance is
any change in a
community’s
environment,
large or small.
Examples of Disturbances A community may experience natural or
human-caused disturbances such as:
Climate Change
Storms
Floods
Fire
Succession Prior to a disturbance, a community may
be in a state of equilibrium (stable and
balanced.)
Characteristics such as limiting factors
hold the community at its carrying
capacity.
However, a disturbance will throw the
community into disequilibrium, forcing the
community to adjust.
Types of Succession There are two types of succession, one
more severe than the other:
Primary Succession
Secondary Succession
Primary Succession When a disturbance is so severe that no
vegetation or soil life remains, primary
succession occurs.
In primary succession, a community
restarts itself from scratch.
It occurs after a large expanse of rock,
sand, or sediment is exposed for the first
time.
Primary Succession Some causes for primary succession to
occur are:
Glacial Retreat
Primary Succession Some causes for primary succession to
occur are:
Lakes Drying Up
Primary Succession Some causes for primary succession to
occur are:
Volcanic Lava or Ash Spreading
How to Primary Succession: Step 1: Pioneer Species
To start the rebuilding process, you will
need a pioneer species.
A pioneer species is a species that is
the first to colonize newly exposed land.
They are normally very well adapted for
colonization.
How to Primary Succession: Step 1: Pioneer Species
Pioneer species tend to have spores or
seeds that can travel long distances.
Examples:
Lyme Grass
How to Primary Succession: Step 1: Pioneer Species
Examples:
Green Algae
How to Primary Succession: Step 1: Pioneer Species
Examples:
Lichen
Primary Succession: Step 2 Get Tiny Plants
Lichens, for example, excel at breaking
down the surface of rocks – which
creates soil.
From this soil,
small plants
will begin to
form.
Primary Succession: Step 3 Get Tiny Insects
As the small plants
begin to grow,
small insects and
worms will begin
to move in.
Primary Succession: Step 4 Thrive!
As new organisms arrive, they will continue to
change the environment by providing more
nutrients and habitat for future arrivals.
Primary Succession: Step 4 Thrive!
As time passes, larger plants establish
themselves, the amount of vegetation
increases, and species diversity increases.
Secondary Succession In secondary succession, a disturbance
dramatically alters an existing
community, but it does not destroy all
living things or organic matter in the soil.
Some of the soil from the previous
ecosystem remains.
As a result, secondary succession occurs
faster than primary succession.
Secondary Succession Some causes for secondary succession
to occur are:
Fires
Secondary Succession Some causes for secondary succession
to occur are:
Logging
Secondary Succession Some causes for secondary succession
to occur are:
Farming
Secondary Succession Because preexisting soil exists in the
community, secondary succession is
much faster.
In The End… Once a community transitions back to a
state of equilibrium, the succession will
lead to a climax community.
A climax community is a stable
community that “completes” the
succession process.
Climax Community The organisms that will thrive in a climax
community are determined by the
climate, soil, and other factors.
Climax Community However, just because a community
arrives to its climax state does not
guarantee that it will always get there
again if a disturbance occurs.