Transcript Biology - Weebly

4-2 What Shapes an
Ecosystem?
Copyright Pearson Prentice Hall
Community Interactions
What interactions occur within
communities?
http://www.youtube.com/watch?v=zSmL2F1
t81Q
Copyright Pearson Prentice Hall
Community Interactions
Symbiosis
Any relationship in which two species live closely
together.
Symbiotic relationships include:
• mutualism
• commensalism
• parasitism
Copyright Pearson Prentice Hall
Community Interactions
Mutualism: both
species benefit from
the relationship.
“Good for me - Good
for you”
Copyright Pearson Prentice Hall
Community Interactions
Commensalism: one
benefits and the other
is neither helped nor
harmed.
“Good for me - Doesn’t
bother you”
Copyright Pearson Prentice Hall
Community Interactions
Parasitism: one
organism lives on or
inside another
organism and harms
it.
“Good for me - Hurts
you”
Copyright Pearson Prentice Hall
Community Interactions
Predation
An interaction in which one
organism captures and
feeds on another organism.
Predator: organism that
does the killing and eating
Prey: food organism being
eaten
Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall
Biotic and Abiotic Factors
Habitat: area
where an
organism lives
and includes both
biotic and abiotic
factors.
Copyright Pearson Prentice Hall
The Niche
The Niche
Niche: the way which an organism lives and its
role in the environment
Copyright Pearson Prentice Hall
Community Interactions
The distribution of these warblers avoids direct
competition, because each species feeds in a
different part of the tree.
Feeding height (m)
18
12
6
Cape May Warbler
Bay-Breasted
Warbler
Yellow-Rumped Warbler
0
Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall
Mutualistm
Parasitism
Commensalism
Copyright Pearson Prentice Hall
Community Interactions
Competition
- Between SAME and DIFFERENT kinds of
organisms
- Compete with each other for available resources
A resource is any necessity of life, such as water,
nutrients, light, food, or space.
Copyright Pearson Prentice Hall
Community Interactions
Competition
FOOD:
Copyright Pearson Prentice Hall
Community Interactions
Competition
SHELTER:
Copyright Pearson Prentice Hall
Community Interactions
Competition
MATES:
Copyright Pearson Prentice Hall
Community Interactions
Competition
SPACE/TERRITORY:
Copyright Pearson Prentice Hall
Community Interactions
Competition
LIGHT:
Copyright Pearson Prentice Hall
Community Interactions
Direct competition: results in a winner and a loser—
with the losing organism failing to survive.
Competitive exclusion principle: no two species
can occupy the same niche in the same habitat at the
same time.
Copyright Pearson Prentice Hall
Copyright Pearson Prentice Hall
Ecological Succession
What is ecological succession?
Copyright Pearson Prentice Hall
Ecological Succession
Series of predictable changes that occurs in a
community over time.
Sometimes, an ecosystem changes in response to an
abrupt disturbance.
At other times, change occurs as a more gradual
response to natural fluctuations in the environment.
Copyright Pearson Prentice Hall
Ecological Succession
Primary Succession
On land, succession that occurs on surfaces where
no soil exists
For example, primary succession occurs on rock
surfaces formed after volcanoes erupt.
Pioneer Species: first species to populate the area
Copyright Pearson Prentice Hall
Ecological Succession
In this example, a volcanic eruption has destroyed
the previous ecosystem.
Copyright Pearson Prentice Hall
Ecological Succession
The first organisms to appear are lichens (symbiosis
of fungus and algae).
Copyright Pearson Prentice Hall
Ecological Succession
Mosses soon appear, and grasses take root in the
thin layer of soil.
Copyright Pearson Prentice Hall
Ecological Succession
Eventually, tree seedlings and shrubs sprout among
the plant community.
Copyright Pearson Prentice Hall
• Primary Succession:
Copyright Pearson Prentice Hall
Ecological Succession
Secondary Succession
Ecosystem changed by natural
events, such as fires.
When the disturbance is over,
community interactions tend to
restore the ecosystem to its original
condition through secondary
succession.
Copyright Pearson Prentice Hall
4-2
Aquatic Succession
is the natural lifespan of a
pond. As time goes on,
sediment fills a pond, and it
becomes more and more
habitable to plants over its
entirety. Eventually there's
enough sediment that the
pond is filled up completely
and is simple a marshy low
spot in the ground.
Copyright Pearson Prentice Hall
4-2
Which of the following is a biotic factor in a
bullfrog's niche?
a. water
b. a heron
c. climate
d. day length
Copyright Pearson Prentice Hall
4-2
An organism’s niche is different from its habitat
because
a. The niche does not include the place where
the organism lives.
b. the niche includes all the conditions under
which the organism lives.
c. the niche includes only abiotic factors.
d. the niche includes only biotic factors.
Copyright Pearson Prentice Hall
4-2
The attempt by organisms of the same or
different species to use a resource at the same
time in the same place is called
a. competition.
b. predation.
c. symbiosis.
d. cooperation.
Copyright Pearson Prentice Hall
4-2
An association between two species in which
one species benefits and the other is neither
helped nor harmed is called
a. symbiosis.
b. mutualism.
c. commensalism.
d. parasitism.
Copyright Pearson Prentice Hall
4-2
When a volcano erupts and completely destroys
an ecosystem, the first species to populate the
area are usually
a. grasses and shrubs.
b. pioneers such as lichens.
c. small plants such as mosses.
d. small animals such as rodents.
Copyright Pearson Prentice Hall