a model that shows one set of feeding relationships among living things
food chain
the original source of all Earth's energy
sun
a model that shows many different feeding relationships among living things
food web
the transfer of energy from one organism to another through a food chain or web
energy flow
a model that shows one set of feeding relationships among living things in water
aquatic food chain
a model that shows one set of feeding relationships among living things on land
terrestrial food chain
a model that shows the available amount of energy in each trophic layer in an ecosystem
energy pyramid
a process in which nitrogen in the atmosphere enters the soil and becomes part of living organisms then eventually returns to the atmosphere
nitrogen cycle
a natural cycle in which mainly carbon dioxide is incorporated into living tissue through photosynthesis and returned to the atmosphere by respiration, decay of dead organisms, and the burning of fossil fuels
carbon cycle
a waste product made by cells of the body; a gas in the air made of carbon and oxygen atoms
carbon dioxide
any organism that can create its own food from inorganic materials
autotroph
an organism that cannot create its own energy and must instead rely on consuming nutrients from other organisms
heterotroph
the position an organism occupies at each level of the food chain
trophic level
an organism that makes its own food; an organism that does not consume other plants or animals
producer
an organism that eats other living things to get energy; an organism that does not produce its own food
consumer
an animal that consumes only plants
herbivore
an animal that eats only other animals
carnivore
an animal that eats plants as well as other animals
omnivore
a non-mutual relationship in which one organism benefits and the other is harmed
parasitism
a relationship in which one species lives off the other and both organisms benefit
mutualism