ENERGY TRANSFER pp 366-369

In an ecosystem energy flows: Sun  autotrophs  heterotrophs producers consumer

PRODUCERS Can make their own food through photosynthesis or chemosynthesis Productivity: energy made by producers (after biological processes) available to consumers

gross primary productivity: rate at which producers capture energy in organic compounds biomass: the amount of organic material produced net primary productivity: the rate at which biomass accumulates (after some is used)

CONSUMERS get energy by eating other organisms - herbivores: eat producers - carnivores: eat other consumers - omnivores: eat producers and consumers - detritivores: feed on “garbage” - decomposers: breakdown big molecules to smaller molecules and recycle materials

ENERGY TRANSFER trophic level: position in a series of energy transfers

Only 10% of the total energy is passed onto the next trophic level 1. lost to biological processes 2. lost as heat 3. not enough at level above to support below

FOOD CHAIN single pathway that traces of energy transfer Producer  herbivore  small  large carnivore carnivore Producer 1˚ consumer 2˚ 3˚

FOOD WEB interrelated food chains SEA OTTER SEA STARS SEA URCHINS KELP

KEYSTONE SPECIES most dominant species in the community Dictates community structure Demonstrated by removal of keystone species from community EX. sea stars in tidepools