Energy Transfer

Entropy is the tendency of a system towards a larger number of random arrangements. Overall, entropy must increase during processes, so a system will tend towards greater disorder. The energy available for organisms decreases from one trophic level to another, because some of the energy is dissipated as heat from each level to the next because of that tendency toward disorder.

The amount of work a system can do is limited by the changes in entropy that occur and cause energy to be dissipated as heat. Systems that dissipate less energy as heat will be able to do more work than systems that dissipate more energy as heat.

c. protozoa

D. None of the above

B. Irreversible Changes

phytoplankton, zooplankton, fish, mammal Phytoplankton are producers, so they produce their own food by using energy from the sun. All other organisms in a food chain obtain energy from other organisms, either producers or other consumers. Zooplankton feed on phytoplankton, so they would obtain their energy from the phytoplankton. Some small fish species feed directly on zooplankton, obtaining their energy from the zooplankton. Some species of aquatic mammals feed on those fish species.

A. Organic Matter

At each trophic level, some of the original energy derived from the sun is lost as heat energy. So, at each trophic level, the amount of available energy is less than the level below it. Animals at higher trophic levels have to consume more organisms to obtain the necessary energy. Organisms at higher trophic levels typically have a smaller biomass, because it takes more organisms to support their life than it does to support the organisms in trophic levels below them.

Gross production is the total energy that is acquired at each trophic level. Net production is the amount of energy that is left after respiration has taken place. Going from one trophic level to the next decreases the energy conversion efficiency, because the net production of each level decreases. Animals expend more energy than plants, and also obtain less energy.

B.10%