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Chapter 3 section 2


organisms that capture energy from sunlight or chemicals and use that energy to produce food


an autotroph, an organism that makes its own food


autotrophs that use light energy to power chemical reactions that convert carbon dioxide and water into oxygen and energy-rich carbohydrates


autotrophs that use chemical energy to produce carbohydrates


organisms that rely on other organisms for their energy and food supply


a heterotroph, an organism that cannot produce its own food or energy


a heterotroph that obtains energy by eating only plants


a heterotroph that obtains energy by eating animals


a heterotroph that obtains energy by eating both plants and animals


a heterotroph that obtains energy by feeding on plant and animal remains and other dead matter


breaks down organic matter

food chain

a series of steps in which an organisms transfer energy by eating and being eaten

food web

feeding relationships among various organisms in an ecosystem form a network of complex interactions

trophic level

each step in a food chain or web

ecological pyramid

a diagram that shows the relative amounts of energy or matter contained within each trophic level in a food chain or web


total amount of living tissue within a given trophic level

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