What Shapes the
Ecosystem?
Biotic and Abiotic Factors
Biotic: All living things in the ecosystems.
– Examples: lions, flowers, and bacteria.
Abiotic: Nonliving factors that shape the
ecosystems.
– Examples: temperature, precipitation and
humidity.
Both determine the growth and survival of
the organism and the productivity of the
ecosystem.
Abiotic and Biotic Factors
Abiotic Factors
Biotic Factors
ECOSYSTEM
Go to
Section:
Habitat
The area in which an organism lives.
– Includes biotic and abiotic factors.
Niche
The job or function of the organism in the
ecosystem.
Includes:
– Food sources
– How it reproduces
– Conditions required to survive
– Time of day most active
No two species can share the same niche
in the same habitat.
Figure 4-5 Three Species of
Warblers and Their Niches
Section 4-2
Cape May Warbler
Feeds at the tips of branches
near the top of the tree
Bay-Breasted Warbler
Feeds in the middle
part of the tree
Spruce tree
Yellow-Rumped Warbler
Feeds in the lower part of the tree and
at the bases of the middle branches
Community Interactions
Competition
Predation
Symbiosis
– Mutualism
– Commensalism
– Parasitism
Competition
When organisms try to use the same
resources in the same place at the same
time.
Resource: any necessity in life.
– Water
– Nutrients
– Light (tall trees block smaller trees)
– Food (Two species of turtles compete for
food).
Competitive Exclusion
In nature, there will
always be a winner (lives)
and a loser (dies).
No two species can
occupy the same niche in
the same habitat at the
same time.
Predation
When one organism captures and feeds
on another.
Predator: organism that does the killing
and eating
Prey: food organism
Symbiosis
Two species live closely together.
Mutualism
Both species benefit
from the situation
– Ants and acacia trees
– Insects and flowers
Commensalism
One organism benefits
but the other is not
helped or harmed.
Barnacles on
whales
Clown fish an sea
anemones
Parasitism
One organisms lives
on or inside an
organism and harms
it.
Fleas, lice, and
parasitic fig
trees!
What type of Symbiosis?
Tapeworms in a dog=
Crabs use seaweed as camouflage=
Leeches that hook onto your body=
Intestinal bacteria in humans produce
Vitamin K=
Moss on the trees=
The acacia trees feed the ants and the
ants protect the tree=
Ecological Succession
Ecosystems change in response to natural
and human disturbances.
– Older inhabitants die out and new ones move
in.
Result from slow changes to the
environment, natural disasters, clearing of
forests.
Primary Succession
On land, on the surfaces
where no soil exist and
bare rocks.
– Occur after volcanic eruption
has covered an area with
ashes or lava, or formed new
islands.
Pioneer Species: First
species to arrive to a new
area.
– Lichens break apart rocks,
rocks and dead lichens add
nutrients, then plants grow.
Secondary Succession
When a disturbance changes the existing
community without removing the soil.
Lands cleared for farming, and wild fires.
Primary Succession
Secondary Succession