Transcript What Shapes an Ecosystem?

Bell Ringer

Bell Ringer

1. Can a food web or food chain ever show abiotic
factors?
2. A food web shows life at the [population,
community, ecosystem] level. (Pick one.)
3. Can an energy pyramid ever be inverted?
4. How much energy passes from one trophic level to
the next?
5. Can a biomass pyramid ever be inverted?
So, how do all those organisms live
together?
What shapes an Ecosystem?
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Ecosystems are defined by the interactions
among the biotic and abiotic factors that exist
within.
The two major factors that these interactions
influence are:
 How organisms survive and thrive.
 The overall productivity of the ecosystem.
What shapes an Ecosystem?
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The area where an organism lives is called its
habitat. An organism’s habitat can also
include a host body, in the case of parasites.
The “role” that an organism plays in its
habitat is called a niche. An organism’s niche
includes:
 The conditions in which an organism lives.
 The means by which an organism survives.
What shapes an Ecosystem?
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For example, a bullfrog’s habitat would be a
pond, lake or stream, as well as the land
nearby.
A bullfrog’s niche would be:
 The food it eats, and is eaten by.
 The cold, watery environment it lives in.
 The means by which it maintains body temp.
 The means by which it reproduces.
Community Interactions
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 Organisms that live
within the same
ecosystem interact with
each other on a
constant basis.
 These interactions may
or may not be
beneficial, to either
party.
Community Interactions
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 Competition: This
interaction occurs
when two organisms
fight over the use of
one resource at the
same time.
 The organisms may
OR may not be of
the same species!
Community Interactions
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 The competitive exclusion principle states that no
two species can occupy the same niche in the same
habitat at the same time.
 This principle means that different species will go
out of their way to avoid competing with one
another.
 This is because competition might lead to death for the
loser!
Community Interactions
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Community Interactions
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Predation: An
interaction in which
one organism
ACTIVELY hunts
and eats another.
Both predator and
prey evolve
adaptations to help
them survive.
Community Interactions
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 Symbiosis: ANY
relationship where two
organisms live closely
together.
 This means the two
organisms are NOT
trying to kill each
other…
 Although there may
still be negative
effects!
Community Interactions
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There are three possible symbiotic
relationships:
 Mutualism, where both organisms benefit.
 Commensalism, where one organism benefits,
and the other is unaffected.
 Parasitism, where one organism benefits, and
the other is harmed.
Community Interactions
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Symbiotic
Relationship
What happens to
organism 1?
What happens to
organism 2?
Mutualism
Benefits (+)
Benefits (+)
Commensalism
Benefits (+)
Unaffected (=)
Parasitism
Benefits (+)
Harmed (-)
Exit Ticket

1. The role that an organism plays in its environment
is its _______.
2. Can two different species occupy the same
ecological niche? Why or why not?
3. Two male deer are butting heads over territory.
What is this an example of?
4. Barnacles attach themselves to a whale to move
around, and the whale is neither helped or harmed.
What is this an example of?
Ecological Succession
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Ecosystems do NOT stay constant over time.
They will change in response to both abrupt
and gradual changes in the environment.
As an ecosystem changes, older inhabitants
die out, and new ones replace them. This
causes the local community to continually
evolve.
We call this process ecological succession.
Ecological Succession
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The type of succession that occurs depends
on whether soil already exists or not.
If NO soil exists, primary succession occurs.
 This happens right after a volcanic eruption,
or after glaciers melt.
If soil already exists, secondary succession
occurs.
 This happens when farmland is abandoned,
or after a wildfire.
Ecological Succession
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In primary succession, there is no soil to start;
just ash and rock.
1. First, pioneer species (often lichens)
populate the area. They break up the rocks
to form soil.
2. These species die, which provides nutrients
to the soil. They are eventually replaced
with new plants.
Ecological Succession
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In secondary succession, good soil already
exists. Only the wildlife is replaced.
1. First, small shrubs and grasses appear.
2. Small bushes and evergreen trees develop
first.
3. Eventually, the evergreens are overtaken by
larger deciduous trees.
Ecological Succession
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Marine ecosystems are also prone to
ecological succession.
 This can take the form of tectonic upheaval, of
temperature changes, or of the addition of
new communities or habitats.
Exit Ticket
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1. A dog is infested with fleas, which feed of
the skin and blood of the dog. What is this
an example of?
2. What type of succession will occur after:
a. a wildfire?
b. a glacier melts?
c. a swarm of locusts eats most of the
vegetation?
Exit Ticket
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 Answer true or false to all statements.
1. Competition only occurs between members of the same
species.
2. Symbiosis includes mutualism, commensalism and
parasitism.
3. Ants move aphids to new leaves, while aphids produce
food the ants like. This is an example of mutualism.
4. The appearance of pioneer species is the first step of
primary succession.
5. Secondary succession only occurs when there is no soil.