Community Ecology

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Community Ecology

• Many Different Interacting Populations

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White Nose

• Sketch a graph of a bat population in the Great
  Smokey NP.
• On your graph, include an insect population for
  the same ecosystem.
• Identify the type of insect population growth and
  explain why it demonstrates that growth.
• White nose is increasing the bat populations
  mortality. What type of limiting factor is white
  nose? Defend your answer.

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The difference between a niche and habitat

• Habitat The area where an organism lives.
• A habitat includes both biotic and abiotic
  factors.
• Niche the full range of physical and biological
  conditions in which an organism lives and the way
  in which the organism uses those conditions.
• The combination of biotic and abiotic factors in
  an ecosystem often determines the number of
  different niches in that ecosystem
• Habitat is the organisms address, the niche is
  its occupation

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Species Relationships based on how organisms
obtain energy (feeding relationships)

• Autotrophs Transform energy from inorganic
  (nonliving) substances into organic substances.
• - Photosynthetic energy from the sun
• - Chemosynthetic energy from inorganic
  chemicals and geothermal energy (sulfur, salt,
  hydrogen sulfide, iron, methane, etc.)
• e.g. Archaebacteria

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• 2) Heterotrophs Obtain their energy from
  consuming organic (living) materials.
• Herbivore consumption of plants
• Carnivore consumption of flesh
• Omnivore consumption of both plants and flesh.
• Detritivore consumption of detritus (dead
  organic matter) i.e. decomposers.

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• All of these feeding relationships result in
  close interactions between different populations.

Interaction Effect on 1st Popn Effect on other Popn Examples
Predation - Lions/Zebras, Snakes/mice
Interspecific Competition - - Elk/Mule Deer, Coyotes/ Vultures
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Study the graph demonstrating hare and lynx
population growth. Describe two patterns
demonstrated b/w predator and prey populations.
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Competitive exclusion principle no two species
can occupy the same niche in the same habitat at
the same time. - results in resource partitioning
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• Symbiotic Relationships A type of interaction
  where both populations live with each other at
  all times.

Interaction Effect on 1st Population Effect on other Population Examples
Parasitism - Tick/Deer, Tapeworm/Cow
Mutualism Ants/aphidsBee/Flower
Commensalism 0 (Not Affected) Nested Bird/Tree, Pilot Fish/Shark
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Parasitism
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Mutualisms Coevolution
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Commensalisms
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Community Structure

• Biodiversity (species diversity) The variety of
  different kinds of organisms that make up a
  community.
• Two Components

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Biodiversity

• Species Richness the total number of different
  species that occupy a community.
• Species Evenness the relative abundance of
  organisms of each species.

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Ecosystem Ecology

• The interactions between the communities and
  their abiotic factors.

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Trophic Structure

• The feeding relationships, and flow of energy
  (abiotic) between organisms in a community.
• The energy stored in producers can be passed
  through an ecosystem along a food chain.

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• Food Chain a series of steps in which organisms
  transfer energy by eating or being eaten.
• Simple only show individual feeding
  relationships.
• In most ecosystems feeding relationships are more
  complex

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Food Webs

• A graphic representation of the feeding
  relationships among the various organisms in an
  ecosystem.
• Links all the food chains in an ecosystem
  together.

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Trophic Levels

• Each step or level in a food chain or food web
• Producers make up the first level, and consumers
  make up the second-fourth.
• 10 producer? 10 consumer? 20consumer?30
  consumer?40consumer
• Limits Each food chain w/in a food web usually
  only has a few links why?

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10 Rule

• Only about 1/10 (10) of the energy stored in the
  organic matter of each trophic level is converted
  to organic matter at the next level.
• What happens to the other 90 of the energy

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• The 10 Rule applies to the overall number of
  individual organisms (as well as overall biomass)
  at each trophic level.
• this explains why there are always fewer large
  predators than prey in ecosystems