gradual process of a species becoming extinct.

a large-scale dying out of a large percentage of all living organisms in an area within a short time.

resources provided by Earth, including air, water, land, all living organisms, nutrients, rocks, and minerals.

overuse of species with economic value—a factor in species extinction.

gradual process of a species becoming extinct.

a large-scale dying out of a large percentage of all living organisms in an area within a short time.

resources provided by Earth, including air, water, land, all living organisms, nutrients, rocks, and minerals.

overuse of species with economic value—a factor in species extinction.

gradual process of a species becoming extinct.

a large-scale dying out of a large percentage of all living organisms in an area within a short time.

resources provided by Earth, including air, water, land, all living organisms, nutrients, rocks, and minerals.

overuse of species with economic value—a factor in species extinction.

habitat loss from separation of an ecosystem into small pieces of land.

any different environmental condition occurring along an ecosystem’s boundaries.

increasing concentration of toxic substances, such as DDT, in organisms as trophic levels increase in food chains or food webs; also called biomagnification

process by which lakes become rich in nutrients from the surrounding watershed, resulting in a change in the kinds of organisms in the lake.

habitat loss from separation of an ecosystem into small pieces of land.

any different environmental condition occurring along an ecosystem’s boundaries.

increasing concentration of toxic substances, such as DDT, in organisms as trophic levels increase in food chains or food webs; also called biomagnification

process by which lakes become rich in nutrients from the surrounding watershed, resulting in a change in the kinds of organisms in the lake.

habitat loss from separation of an ecosystem into small pieces of land.

any different environmental condition occurring along an ecosystem’s boundaries.

increasing concentration of toxic substances, such as DDT, in organisms as trophic levels increase in food chains or food webs; also called biomagnification

process by which lakes become rich in nutrients from the surrounding watershed, resulting in a change in the kinds of organisms in the lake.

habitat loss from separation of an ecosystem into small pieces of land.

any different environmental condition occurring along an ecosystem’s boundaries.

increasing concentration of toxic substances, such as DDT, in organisms as trophic levels increase in food chains or food webs; also called biomagnification

process by which lakes become rich in nutrients from the surrounding watershed, resulting in a change in the kinds of organisms in the lake.

Ordovician Period

Devonian Period

Permian Period

Triassic Period

Cretaceous Period

Ordovician Period

Devonian Period

Permian Period

Triassic Period

Cretaceous Period

Ordovician Period

Devonian Period

Permian Period

Triassic Period

Cretaceous Period

Ordovician Period

Devonian Period

Permian Period

Triassic Period

Cretaceous Period

Ordovician Period

Devonian Period

Permian Period

Triassic Period

Cretaceous Period