Unit 12 Vocabulary

10% Rule Only 10% of the energy present at one feeding is passed on to the next feeding level

Commensalism A symbiotic relationship between species in which one species is helped and the other is unaffected

Energy Pyramid Diagram that demonstrates the flow of energy through a food chain

Mutualism A symbiotic relationship between two species in which both species benefit

Parasitism A symbiotic relationship in which one organism (parasite) benefits and the other (the host) is generally harmed but not killed

Symbiosis A close relationship between two species

Producer An organism that can make it’s own energy through photosynthesis or chemosynthesis

Primary Consumer In a food chain, organisms that eat producers

Secondary Consumer In a food chain, an organism that feeds on producers (plant-eaters); also called a predator

Tertiary consumers In an ecosystem, a predator that feeds on other predators

Decomposers An organism that breaks down tissue and releases nutrients and carbon dioxide back into the ecosystem

Omnivore an organism that eats both plants and animals.

An organism that feeds only on plants Herbivore An organism that feeds only on plants

Carbon Cycle The continual transfer of carbon dioxide and oxygen between living things and the environment

Water Cycle Cycle in which water moves through the environment, through the process of evaporation, condensation and precipitation

Nitrogen Cycle In the environment, the movement of nitrogen between the living and non-living parts of an ecosystem

Natural Selection Process by which organisms change over time as those with traits best suited to an environment pass their traits to the next generation.

Survival of The Fittest A natural process resulting in the evolution of organisms best adapted to the environment

Food Chain Series of stages that shows the transfer of energy from producers to consumers to decomposers

Food Web In an ecosystem, arrangement of several overlapping food chains

Predator Animal that kills and eats other animals

Host Organism that supports a parasite

Parasite Organism that feeds on cells, tissues or fluids of another living organism