Community Ecology

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Community Ecology

• 1. Community- group of populations occupying same
  place at same time
• 2. Includes all living organisms
• 3. Habitat place niche pattern of living

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Niche

• 1. How organisms utilize their environment
• 2. Fundamental niche- niche species capable of
  occupying utilizing
• 3. Realized niche- niche species actually
  occupies uses

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Competitive Exclusion

• 1. If resources limited, no two species can
  occupy same niche indefinitely
• 2. Competition drives one species to extinction
• 3. Partitioning niche avoids competition
• 4. Different areas of habitat or different food
  sources

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Predator Prey Relationships

• 1. Predators control prey populations, prey
  control predator populations
• 2. Predation provides strong selective pressures
  on prey populations
• 3. Predators prey coevolve

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Predator Prey Examples

• 1. Removal of large carnivores explosion in
  white-tailed deer population
• 2. Mesozoic fish could crush open mollusc
  shells mollusc evolved thicker shells
  defensive spines

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Mimicry

• 1. Batesian mimicry
• 2. Mullerian mimicry

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Batesian Mimicry

• 1. Harmless species resembles dangerous or
  unpleasant species
• 2. Monarch viceroy butterflies
• 3. Coral snake mountain kingsnake

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Mullerian Mimicry

• 1. Two or more unrelated but protected species
  resemble one another
• 2. Group defense
• 3. Butterflies bees wasps

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Symbiotic Relationships

• 1. Two or more species living together in
  specific relationships, at least one benefits
• 2. May coevolve
• 3. Commensalism, mutualism, parasitism

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Commensalism

• 1. One species benefits, other neither benefits
  nor harmed
• 2. Many organisms physically attach themselves to
  other organisms, barnacles

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Clown Fish Sea Anemones

• 1. Clown fish not harmed by paralyzing tentacles
• 2. Clown fish feed on detritus left from
  anemones meals

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Mutualism

• 1. Cooperation between species mutually benefits
  both
• 2. Coevolution of angiosperms insects, some
  plants have one specific pollinator
• 3. Ants acacias
• 4. Humans dogs?

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Ants Acacias

• 1. Ants live in acacia, drive other insects away
• 2. Acacias produce Beltian bodies at the tips of
  their leaves, function only as protein-rich food
  for ants

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Parisitism

• 1. One organism serves as host to another
  organism
• 2. Usually to the hosts disadvantage, but
  parasite doesnt kill host
• 3. Parasite much smaller than host
• 4. External, lice internal, tapeworms pinworms

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Brood Parisitism

• 1. Birds lay eggs in the nests of another species
• 2. First action of brood parasite, kills other
  nestlings
• 3. Host parents raise brood parasite

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