Autotroph Organism that can capture energy from sunlight or chemicals and use it to produce its own food from inorganic compounds; also called a producer.
Producer Organism that can capture energy from sunlight or chemicals and use it to produce food from inorganic compounds; also called an autotrophs.
Photosynthesis Process by which plants and some other organisms use light energy to convert water and carbon dioxide into oxygen and high energy carbohydrates such as sugars and starches.
Chemosynthesis Process by which some organisms, such as certain bacteria, use chemical energy to produce carbonhydrates.
Heterotrophs Organism that obtains energy from the foods it consumes; also called a consumer.
Consumers Organism that relies on other organisms for its energy and food supply.
Herbivores Organism that obtains energy by eating only plants.
Carnivores Organism that obtains energy by eating animals.
Omnivores Organism that obtains energy by eating both plants and animals.
Detritivores Organism that feeds on plant and animal remains and other dead matter.
Decomposers Organism that breaks down and obtains energy from dead organic matter.
Food Chain Series of steps in an ecosystem in which organisms transfer energy by eating and being eaten.
Food Web Network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem.
Trophic Level Step in a food chain or food web.
Ecological Pyramid Diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or food web.
Biomass Total amount of living tissue within a given trophic level.
Key Concept Where does the energy for life processes come from? Sunlight is the main energy source for life on Earth.
Key Concept How does energy flow through living systems? Some types of organisms rely on the energy stored in inorganic chemical compounds.
Key Concept How efficient is the transfer of energy among organisms in an ecosystem? Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers).