lect5...1 - Energy Flow and Trophic Pyramids Human Fish...

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Energy Flow and Trophic Pyramids Human Human Human ↑↑ Fish Cow Deer Algae Grass Forest Which would you recommend as the best food chain to sustain humans?
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Unlike nutrients, energy cannot be recycled efficiently. Continuous influx of energy is required; the source is typically the sun. Other forms of energy can serve as a basis for ecosystems such as geothermal energy for hydrothermal vent communities. Communities can often be arranged as a food chain with different trophic levels . A food chain is a pathway along which food is transferred from one trophic level to the next trophic level. - based on the main source of nutrition and are unbranched .
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Trophic Level 2° Carnivore 3º consumers 1° Carnivore 2º consumers Herbivore 1º consumers Plant 1º producers Detritivore decomposer heterotrophs autotrophs Examples Autotrophs: “self-feeders” Use energy to convert carbon dioxide (or some other form of carbon or other element) into biomass. i.e., photosynthetic plants or chemoautotrophic bacteria Heterotrophs: “other feeders” Depend directly or indirectly on autotrophs. Decomposers: feed on nonliving organic matter. Mostly bacteria and fungi; however, some animals are decomposers. lion antelope grass roadrunner lizard grasshopper grass
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In reality, trophic relationships are more complex than simple linear chains among organisms. Food webs are branched pathways that are used to represent how food is transferred among organisms in a community or an ecosystem. Food webs can be thought of as a group of interlocking food chains. . bobcat weasel shrew mouse predaceous insect 1 predaceous insect 2 grasshopper 1 grasshopper 2 leaf beetle autotroph 1 autotroph 2 autotroph3
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Trophic levels tend to break down in nature: (1) many organisms are omnivores that feed on more than one trophic level.
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This note was uploaded on 04/19/2008 for the course BIOL 5c taught by Professor Walton during the Spring '08 term at UC Riverside.

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lect5...1 - Energy Flow and Trophic Pyramids Human Fish...

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