Interdependence and interactions in an ecosystem

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Interdependence and interactions in an ecosystem
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• Interpret interactions among organisms exhibiting
  predation, parasitism, commensalism and mutualism
• Identify and illustrate that long-term survival
  of a species is dependent on a resource
• Investigate and explain the interactions in an
  ecosystem including food chains, food webs and
  food pyramids

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• Biotic factors living parts of the ecosystem
  (ex trees, birds, etc.)
• Abiotic factors non-living parts of the
  ecosystem (ex rocks, water, etc.)
• Population ? Community ? Ecosystem
• Population group of organisms of the same
  species living together
• Community groups of populations living in the
  same area
• Ecosystems community all the non-living
  surroundings

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Name the Biome
Temperate Forest
Desert
Tundra
Grasslands
Tropical Rainforest
Tiaga
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Predator Prey

• Predators feed on other organisms.
• Prey are the organisms that get eaten.
• The prey population needs to be larger than the
  predator population. As the prey population
  increases, the predator population increases. If
  the prey population decreases, the predator
  population decreases.
• Predation keeps population size within the limits
  of available resources.

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Symbiosis

• Symbiosis means living together--there are 3
  types of symbiotic relationships
• Parasitism the host is harmed and the parasite
  benefits (ex human and a tapeworm)
• Commensalism one organism is not harmed nor
  benefited and the other organism benefits (ex
  tree and a bird)
• Mutualism both organisms benefit (ex clown fish
  and an anemone)

Host Parasite
Organism Unaffected Organism Benefited
Organism Benefited Organism Benefited
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Food Chain

• Food Chain represents the flow of energy in an
  ecosystem the arrows represent the direction of
  energy flow and are called trophic levels. There
  are usually 3-4 trophic levels in a food chain
  but no more than 5 levels
• Grass ? Insect ? Bird ? Hawk
• (plant) (herbivore) (carnivore)
  (carnivore)
• Producer organisms that undergo photosynthesis
  (grass) also called autotrophs
• Consumer organisms that must eat
  producers/consumers also called heterotrophs
• Primary consumer these organisms eat the
  producers (insects)
• Secondary consumer these organisms eat the
  primary consumers (bird)
• Tertiary consumer these organisms eat the
  secondary consumers (hawk)

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Food Chain Cont.

• Scavengers organisms that feed on dead animals
  (ex vultures)
• Decomposers organisms that break down dead
  organic material (ex fungi)
• Herbivores eat only producers
• Carnivores eat only consumers
• Omnivores eat producers and consumers

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Food Webs

• Food Webs are interconnected food chains
• Food chain 1 seeds ? chipmunk ? grizzly bear
• Food chain 2 berries ? chipmunk ? goshawk

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Pyramids
There must always be more prey than predators
because the predators can not use all the energy
that is consumed from the prey. The lower an
organism is on the food chain, the higher the
numbers of these organisms. The more organisms
there are at a trophic level, the more mass the
group of organisms has.

Energy Pyramid
Number Pyramid
Biomass Pyramid
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Biological Magnification

• If a chemical or toxin (ex DDT) enters the food
  chain at a low level (ex grass) the amount of
  that chemical increases as you move up the food
  chain.