Competition, Predation, and Symbiosis

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Competition, Predation, and Symbiosis

• Interactions within a community

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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

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Adaptations

• Organisms are adapted to survive in their niche
• Adaptations Behaviors or physical traits that
  allow organisms to live successfully in their
  environments

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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

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Remember

• An organism does NOT change its traits to suit
  the environment
• Adaptations that can be changed through natural
  selection are GENETIC

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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

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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

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Predation

• When one organism kills another for food
• Predator The hunter
• Prey The hunted
• Both are adapted to help them survive

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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

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Symbiosis

• a close relationship between two species, where
  at least one of the species benefits
• Three types Mutualism, commensalism, parasitism

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Mutualism

• Were friends!
• Both organisms benefit from the relationship

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Commensalism

• We are sort of friendsSometimes you open my
  locker for me when its stuck because you are
  stronger then me
• One organism benefits, and the other is neither
  helped or harmed

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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)

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Common parasites
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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.

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• Galls Growths on plants caused by insects,
  fungi, bacteria, viruses. Very common.

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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)

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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)

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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)

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The Study
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Other parts of the Isle Royale Community

• Balsam Fir
• Ravens
• Red Fox
• Red Squirrels
• Moose ticks
• Beaver
• Snowshoe hare