Transcript Ecosystems
Ecosystems
Interactions among living things
Natural Selection:
A process by which characteristics that
make an individual better suited to it's
environment become more common in
the species.
Sometimes referred to as “survival of
the fittest”
How Does Natural Selection work?
1.
2.
Those with the unique characteristics best
suited for their environment will survive and
produce offspring.
End result = ADAPTATIONS
English Peppered Moth –Natural
selection in action
dark moth - random mutation
not as common
camouflaged moth
Soot covered tree
England 1800’s
Adaptations
Behaviors or physical characteristics that
allow organisms to live successfully in
their environment
Shell for
protection
Long neck to
reach leaves
Long shallow
roots, needles
to protect from
animals
Niche
An organisms’ role in an ecosystem = niche.
Niche and Habitat are different
◦ Address of an organism = Habitat
◦ “Job” or “Profession” = Niche
Organism = tree
Habitat = Forest
Niche = produce oxygen
provide home for birds
Explain why two organisms
cannot occupy the same niche:
If two species occupy the exact same
niche in nature, one will die off due to
competition for limited resources.
Video Link – Niche, Competition, Predation, and Symbiosis
http://www.youtube.com/watch?v=D1aRSeT-mQE
Three major types of
interactions among organisms:
Competition
Predation
Symbiosis
Competition:
The struggle between
organisms to survive as they
attempt to use the same
limited resources.
Predation:
An
interaction in which
one organism kills
another for food.
Predator or Prey:
Predator - organism that does
the killing
Prey – organism that is killed.
Effect of predation on population size:
What variable is
plotted on the
years
x-axis? ______
What two variables
are plotted on the
# of moose
y-axis? ________
# of wolves
and __________
Effect of predation on population size:
How did the moose
population change
between 1965 and
It increased
1972 ___________
How did the wolf
population change
between 1973 and
It increased
1976? __________
Effect of predation on population size:
How might the
change in moose
population have lead
to the change in wolf
population?
– The wolf preys on
the moose so more
moose meant more
food for the wolf.
Effect of predation on population size:
How might disease in
the wolf population
one year affect the
moose population the
next year?
– Disease in the wolf
population might
cause some to die.
With less predators,
the moose
population would
most likely increase.
Examples of Predator Adaptations
Cheetah
speed
Owl eyes
Jelly fish venom
Defense Strategies of Prey
Mimicry
Protective Covering
False Coloring
Warning color
Camouflage
Video Link on Predator and Prey Interactions
http://www.youtube.com/watch?v=vZynrBA91fY
Interactions – Three Types
Symbiosis – a close relationship in nature
that benefits at least one species
Bacteria from gut of termite
Termites
Symbiosis
Mutualism
Both species benefit
Commensalism
One species benefits, but the other isn’t
harmed or helped.
Parasitism
One species benefits and the other is
harmed.
The one benefiting is the parasite
The one being harmed is a host