food webs

Community

All populations of different species interacting in an area

Ecosystem

A community plus abiotic factors like climate and nutrients

Food web

A summary of consumption interactions (overlapping food chains)

Food chain

A single path of energy transfer in an ecosystem

Energy flow rule

Energy cannot be created or destroyed—only transformed

Primary producer

Organism that makes its own food from inorganic sources

Gross primary productivity (GPP)

Total chemical energy produced by producers

Cellular respiration (R)

Energy producers use to make ATP

Net primary productivity (NPP)

Energy invested in growth/offspring (GPP – R)

Biomass

Chemical energy stored in organic tissue

Trophic level

Organisms that get energy from the same type of source

Primary consumer

Organism that eats primary producers

Secondary consumer

Organism that eats primary consumers

Tertiary consumer

Organism that eats secondary consumers

Decomposer

Gets energy from dead organisms

Efficiency of energy transfer

About 10% of energy is passed to the next level

Where the other 90% goes

Lost as heat or used for cellular respiration

Energy pyramid pattern

Biomass decreases at higher trophic levels

Energy efficiency in mammals

Large mammals are more efficient than small mammals

Energy efficiency in ectotherms vs endotherms

Ectotherms convert energy to biomass more efficiently

Most efficient trophic level for humans

Primary consumers (eat plants)

Millipede trophic level

Primary consumer (eats detritus/plant matter)

American toad trophic level

Secondary consumer

Fox trophic level

Tertiary consumer