Community Interactions

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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
• 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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Competitive exclusion principle When two
different populations try to occupy the same
niche, one usually out competes the other and
ultimately it disappears from the area.
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Populations can minimize competition by a process
called resource partitioning. Resource
partitioning allows populations to use the same
resource only at different times or positions.
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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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What are the different kinds of symbiosis?
Mutualism

• Parasitism

Commensalism
both organisms benefit
one organism benefits
one organism benefits
one organism is unaffected
one organism is harmed
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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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Mutualism both benefit
Example 2 Moray Eel with Cleaner Fish
Moray Eel gets a clean mouth Cleaner Fish gets a
meal
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Mutualism both benefit
Example 5 Antelope with Oxbird
Antelope gets rid of parasites Oxbird gets a meal
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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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Example 3 Cattle with cattle egrets
Cattle stir up insects as they eat grassEgrets
hang around and eat insects
Commensalism one benefits, one is unaffected
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Example 4 Clown fish with anemone
Clown fish gets protection Anemone is unaffected
Commensalism one benefits, one is unaffected
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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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Example 1 Acacia plant with ant galls
Ants lay eggs on acacia treeAcacia covers the
infected area with brown flesh (gall)
Parasitism one benefits, one is harmed
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Example 6 Taenia worm in human eye
Worm infects human blood streamHuman may go blind
Parasitism one benefits, one is harmed
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Identify these relationships