Larger consumers eat smaller consumers, who eat producers or decayed matter {food chain}|. Producer number and mass must be larger than consumer number and mass. Food chains can start with microorganisms grazing on decayed matter. Visible organisms eat zooplankton. Larger organisms are at food-chain top.
Smaller organisms have higher metabolism per gram. Plants use 3% of received light. Animals use 5% to 10% of food.
Food chains or food webs have hierarchies of predatory levels {trophic level}, by organism sizes. For example, ocean algae phytoplankton are at Level 1. Krill zooplankton are at Level 2. Haddock, sardine, anchovy, and herring are at Level 3. Whiting, snapper, and halibut are at Level 4. Cod and tuna are at Level 5. Saithe are at Level 6. Higher levels grow more slowly.
Dead organisms {detritus}| are 30% of ocean food and 90% of forest food.
Consumer organisms {holozoic} can digest food.
Animals can be plant eaters {herbivore}|.
Animals can be meat eaters {carnivore, food chain}|.
Animals {omnivore}| can eat all food types. Omnivores have the most and the most-varied activities.
Bacteria and other microconsumers {saprotroph} {saprophytic organism} can absorb dead and decaying organic matter.
Producer organisms {autotroph} can synthesize food from inorganic materials, by photosynthesis or chemosynthesis.
Consumer organisms {heterotroph} can eat autotrophs or dead organic matter.
Bacteria and other microconsumers {osmotroph} can intake nutrients from water.
Predators and macroconsumers {phagotroph} eat other living organisms.
Organisms {aerobe}| can use oxygen as electron acceptors to oxidize other molecules, to get energy.
Organisms {anaerobe}| can use sugars, not oxygen, to get energy.
Organisms {facultative aerobe} can use either oxygen or sugars but prefer oxygen to get energy.
Organisms {obligate anaerobe} can use sugars to get energy.
Ocean organisms {benthos} can be bottom dwellers.
Ocean organisms {nekton} can be swimming animals.
Ocean organisms {pelagic}| can be open-water dwellers.
In oceans, animal masses in deep scattering layer (DSL) rise at night and fall by day {vertical migration}|.
Organisms {plankton}| can float.
Plankton {phytoplankton} can be floating plants.
Plankton {zooplankton} can be miniscule animals.
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Date Modified: 2022.0225