17 and 18. Human influences - Organisms and their environment and Human infuences on ecosystem

Ecosystem

A biological community of interacting organisms and their physical environment.

producer

An organism that can make its own food.

consumer

An organism that obtains energy by feeding on other organisms

herbivore

A consumer that eats only plants.

carnivore

A consumer that eats only animals.

trophic level

Each step in a food chain or food web

decomposer

organism that breaks down and obtains energy from dead organic matter

food chain

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

food web

A community of organisms where there are several interrelated food chains

combustion

the process of burning something

carbon cycle

The organic circulation of carbon from the atmosphere into organisms and back again

deforestation

The removal of trees faster than forests can replace themselves.

Eutrophication

excessive richness of nutrients in a lake or other body of water, frequently due to runoff from the land, which causes a dense growth of plant life and death of animal life from lack of oxygen.

fossil fuels

Coal, oil, natural gas, and other fuels that are ancient remains of plants and animals.

greenhouse gases

Gases in Earth's atmosphere that trap heat near the surface

acid rain

rain containing high amounts of chemical pollutants

species diversity

The number and relative abundance of species in a biological community.

overgrazing

Destruction of vegetation caused by too many grazing animals consuming the plants in a particular area so they cannot recover

erosion

Processes by which rock, sand, and soil are broken down and carried away

conservation

Protecting and preserving natural resources and the environment

species

A group of organisms that are closely related and can mate to produce fertile offspring