Interactions Among Organisms

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Interactions Among Organisms

• Ecology

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TROPHIC LEVELS

• Organisms interact with members of their own
  species and with those of other species.
• Relationships between or among different
  organisms are known as biotic factors.
• Interaction of a community w/ its environment is
  an ecological system or ecosystem.
• Each organism represents a feeding step, or
  trophic level, in the passage of energy and
  materials.

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Biotic Factors

• An Ecosystem possesses both LIVING COMPONENTS OR
  BIOTIC FACTORS and NONLIVING OR ABIOTIC FACTORS.
• The Living Components of the environment are
  called Biotic Factors. They include all the
  Living Things that affect an organism. Biotic
  Components are often categorized as Producers,
  Consumers, and Decomposer.

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FLOW OF ENERGY IN ECOSYSTEMS

• Energy in an Ecosystem FLOWS from the SUN to
  Producers (autotrophs) then to Organisms that Eat
  the Producers, then to Organisms that feed on
  other Organisms (Consumers).
• Producers are Autotrophic Organisms. Autotrophs
  have the capability of carrying out
  Photosynthesis, and making food for themselves
  and storing some for other Organisms to consume. 
  Examples are plants, some bacteria, and algae.

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Flow of Energy in an Ecosystem

• Consumers (heterotrophs) can be broken into
  different groups depending on what they EAT
• Decomposers Consumers who feed on Remains of
  Dead Plants and Animals.
• Herbivores (First order consumer) Eat Producers
  or Plant Eaters.
• Carnivores (Second or Third order consumer) Eat
  other Consumers. Meat Eaters.
• Omnivores (Second or Third order consumer) Eat
  Both Producers and Consumers. Plant and Meat
  Eaters (US).

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ENERGY FLOW THROUGH AN ECOSYSTEM
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FOOD CHAINS Webs

• Food Chain - The transfer of materials and
  potential energy from organism to organism
  (trophic level to trophic level).
• A food chain represents one possible route for
  the transfer of materials and energy through an
  ecosystem
• Food Web - All the possible feeding relationships
  that exist in an ecosystem

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Food Chain
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FOOD CHAIN/ WEB
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Pyramid of Energy

• Energy flows through ecosystems from producers to
  the various levels of consumers. Each time an
  organism eats another, not all the energy is
  transferred. Only about 10 of the energy of a
  producer is transferred to the consumer that eats
  it. Therefore, there is a progressive loss of
  energy at each level of a food chain. We can
  represent the amount of energy at each level as a
  part of a energy pyramid.

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PYRAMID of BIOMASS

• It is possible to estimate the mass of all the
  organisms living in a given area or ecosystem.
• This estimation is known as the biomass. If the
  mass of the producers and each type of consumer
  is recorded, a pyramid can be constructed showing
  that the biomass of the producers is generally
  far greater than that of the consumers.

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