APES - U1

Genetic diversity

The variety of genes and inherited traits within a species or population.

Habitat

The place where an organism lives and finds the resources it needs.

Ecosystem

A community of organisms and the nonliving parts of their environment interacting together.

Biosphere

All parts of Earth where life exists, including land, water, and the atmosphere.

Troposphere

The lowest layer of Earth’s atmosphere, where weather occurs and most air and clouds are found.

Stratosphere

The atmospheric layer above the troposphere that contains the ozone layer.

Hydrosphere

All of Earth’s water, including oceans, lakes, rivers, groundwater, ice, and water vapor.

Geosphere

The solid parts of Earth, including rocks, soil, landforms, and Earth’s interior.

Trophic level

An organism’s feeding position in a food chain or food web.

Autotrophs

Organisms that make their own food, usually using sunlight or chemical energy; also called producers.

Heterotrophs

Organisms that obtain energy by eating other organisms or organic matter; also called consumers.

Decomposers

Organisms, such as many fungi and bacteria, that break down dead organisms and wastes and recycle nutrients.

Detritivores

Organisms that eat dead organic matter and waste, breaking it into smaller pieces.

Biomass

The total mass of living organic matter in a given area or at a particular trophic level.

Ecological efficiency

The percentage of energy or biomass transferred from one trophic level to the next.

Pyramid of energy flow

A diagram showing how much energy is available at each trophic level in an ecosystem, with less energy available at higher levels.