Transcript Competition, Predation, and Symbiosis

Competition, Predation, and
Symbiosis
Interactions within a community
Niche (nitch or neesh)
 The role of an organism in its habitat
 each species is specially adapted to its niche
 Includes:
Type of food it eats
How it gets its food
What eats it (predators)
Conditions it requires to survive and reproduce
Adaptations
 Organisms are adapted to survive in
their niche
Adaptations: Behaviors or physical traits
that allow organisms to live successfully
in their environments
How do organisms become
adapted to their niche? Natural
Selection
 Natural Selection:
 How a trait that
makes an individual
better suited to its
environment may
become common in
the species
 Survival of the fittest
 Individuals who are
best suited to their
environment are more
likely to survive and
reproduce and pass
their traits on
 This makes their
unique traits more
common in the
species
 Results in
adaptations
Remember…
 An organism does
NOT change its
traits to suit the
environment
 Adaptations that can
be changed through
natural selection are
GENETIC
Competition
 The struggle between
organisms to survive as
they try to use the same
resources
 If organisms try to occupy
the same niche, they are
competing.
 One will either die out or
move
 Organisms avoid
competition by occupying
slightly different niches
Examples:
Lions and Hyenas compete for the
same food
Kudzo, and invasive plant in the south,
crowds out the native plants in a
competition for space
Predation
 When one organism
kills another for food
 Predator: The
hunter
 Prey: The hunted
Both are adapted to
help them survive
Predator Prey Interactions
Predators depend on prey to survive
When the population of prey is low, the
population of predators will go down
When the prey population goes up,
predator populations tend to go up as well
It is a cycle
Symbiosis
 a close relationship between two
species, where at least one of the
species benefits
Three types: Mutualism, commensalism,
parasitism
Mutualism
 We’re friends!
 Both organisms benefit from the
relationship
Commensalism
We are sort of friends…Sometimes you
open my locker for me when it’s stuck
because you are stronger then me…
 One organism benefits, and the other is
neither helped or harmed
parasitism
 We are NOT friends. We are enemies.
One organism lives on or in another
organism and causes harm
Sometime a parasite lives on its host
permanently (tapeworms), sometimes it
is temporary (mosquitoes)
Common parasites
Other types of parasites
 Brown headed
cowbird: lays its
eggs in other birds
nest to be raised by
other birds at the
expense of their
own young.
 Galls: Growths on
plants caused by
insects, fungi,
bacteria, viruses.
Very common.
Moose and Wolves of Isle
Royale
 Isle Royale is an island in
Lake Superior
 There is a population of
moose and wolves that lives
there.
 The relationship between the
moose and wolves has been
studied since 1958. This is
the longest predator prey
study ever done.
•There are no permanent
populations of people
living on Isle Royale
•It is a national Park
(hunting is illegal)
The Moose
 The first moose arrived around 1900 by
probably swimming the 15 miles from Canada
 Wolves are its only predator
 Moose need to eat about 40 lbs of food/day
to survive
 Ticks, food supply, and weather all affect the
survival of moose (limiting factors)
The Wolf
 They arrived on Isle Royale around 1950 by
using an ice bridge from Canada (probably)
 Moose are its main food source (90%). They
will also eat snowshoe hare and beavers
 Beside starvation, they die due to fights with
other wolves over food (competition)
The Study
Other parts of the Isle Royale
Community
Balsam Fir
Ravens
Red Fox
Red Squirrels
Moose ticks
Beaver
Snowshoe hare