Ecosystems
Essential Standards
Bio.2.1 Analyze the interdependence of living organisms within their
environments.
Energy Transfer
• Energy flows from sun to autotrophs to consumers then to
decomposers
Producers
• Autotrophs that produce their own organic molecules (carbohydrates)
• Ex. Plants, bacteria, and some protists
• Plants are photosynthetic
• Bacteria are chemosynthetic
• Use energy from inorganic molecules to produce carbohydrates
Biomass
• Biomass – all organic material in the ecosystem
• Producers add biomass to ecosystem by producing organic molecules
Consumers
• Heterotrophs such as animals, fungi, bacteria, and some protists
consume organic molecules
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Herbivores
Carnivores
Omnivores
Detritivores (decomposers)
Energy Flow
• Energy flow – transfer of energy from organism to organism
• Trophic Level – indicates organism’s position in the energy transfer
• ~3-4 levels
Energy Flow
• Energy in trophic levels
• ~10% of total energy consumed is passed to next trophic level
• Some energy is ”lost” as heat
Energy Flow
• Food Chain – single pathway of feeding relationships among
organisms resulting in energy transfer
• Food Web – interrelated food chains in an ecosystem