Community

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Community Interactions
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14.2 Community Interactions

• when organisms live together in an ecological
  community they interact constantly.
• Three types of interactions
• Competition
• Predation
• Symbiosis

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Competition- competing for resources

• occurs due to a limited number of resources
• Intraspecific competition
• Interspecific competition
• Resource- any necessity of life. water,
  nutrients, light, food.
• Competitive exclusion principle- no two species
  can occupy the same niche in the same habitat at
  the same time

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Predation

• Predation- when an organism captures and feeds on
  another organism.
• Predator- hunter
• Prey- hunted

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Symbiosis

• Symbiosis- any relationship where two species
  live closely together.
• (3 types)
• Mutualism
• Commensalism
• Parasitism

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Symbiosis

• Mutualism- both species benefit from a
  relationship.
• Lichens (fungus and Algae)

One example is the lichens, little non-descript
patches of stuff you see growing on rocks and
tree bark. This is a symbiosis, consisting of a
fungus and an alga. The fungus provides a
protective home for the algae, and gathers
mineral nutrients from rainwater and from
dissolving the rock underneath. The alga gathers
energy from the sun. There are thousands of
species of lichen in the world actually
thousands of species of fungi with just a few
species of algae which can form a partnership
with almost any of them.
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Symbiosis

• Commensalism One member of a symbiotic
  relationship benefits and the other is neither
  helped or harmed
• Ex. Holes used by bluebirds in a tree were
  chiseled out by woodpeckers after it has been
  abandoned

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Symbiosis

• Parasitism- One creature benefits and one
  creature is harmed
• Ex tapeworm. Feeds in a humans intestines
  absorbing his/her nutrients.

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Relationships
Symbiosis Living Together
a) commensalism
b) mutualism
c) parasitism
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Identify these relationships