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13.2 Biotic and Abiotic Factors
KEY CONCEPT
Every ecosystem includes both living and nonliving
factors.
13.2 Biotic and Abiotic Factors
MI State Standards
• L3.p2A
Describe common relationships among
organisms and provide examples of producer/consumer...
• L3.p2B
Describe common ecological relationships
between and among species and their environments.
• L3.p2D
Explain how two organisms can be mutually
beneficial and how that can lead to interdependency.
• L3.p3B Distinguish between the living (biotic) and nonliving
(abiotic) components of an ecosystem.
13.2 Biotic and Abiotic Factors
An ecosystem includes both biotic and abiotic factors.
• Biotic factors are living things.
– plants
– animals
– fungi
– bacteria
plants
13.2 Biotic and Abiotic Factors
• Abiotic factors are nonliving things.
– moisture
– temperature
– wind
– sunlight
– soil
sunlight
moisture
13.2 Biotic and Abiotic Factors
Changing one factor in an ecosystem can affect many
other factors.
• Biodiversity is the assortment, or variety, of living things in
an ecosystem.
– Compare two plots of land:
• A 400 acre corn field, with over 1,500,000 corn plants.
• A small 1-acre wild plot with trees, shrubs, grasses, mosses, small
mammals, birds, insects, etc., with many 2,000 organisms.
– Which has more biodiversity?
• Rain forests have more biodiversity than other locations in
the world, but are threatened by human activities.
13.2 Biotic and Abiotic Factors
• A keystone species is a species that has an unusually large
effect on its ecosystem.
– The addition or removal of a keystone species has huge
environmental impacts on an ecosystem.
When sea otters near
Russia were hunted to near
extinction, they no longer
ate the sea urchins, who
then consumed all the sea
kelp. The sea kelp were the
breeding grounds for
salmon, whose population
dropped significantly.
keystone
13.2 Biotic and Abiotic Factors
• Keystone species form and maintain a complex web of life.
creation of
wetland
ecosystem
increased waterfowl
Population
keystone species
increased
fish
population
nesting
sites for
birds
13.2 Biotic and Abiotic Factors
With the person next to you, discuss the previous slide,
showing the family of beavers in their den.
1. How does dam building affect fish populations?
2. What effect does the increase in fish populations have
on the pond?
3. What is the overall effect of damming?
13.2 Biotic and Abiotic Factors
With the person next to you, discuss the previous slide,
showing the family of beavers in their den.
1. How does dam building affect fish populations?
The dam creates a pond from free-flowing water, which
allows a greater number and variety of fish to live and
reproduce in the water.
2. What effect does the increase in fish populations have
on the pond?
Fish attract species to the pond that feed on them.
3. What is the overall effect of damming?
Increase in biodiversity.