Grasses

Gorillas

Shrubs

Bears

River sediments are deposited along a waterfront consisting of barren rock, resulting in the establishment of moss and grass communities.

A wildfire burns through the underbrush of a hardwood forest, freeing up available sunlight for new understory brush.

A windstorm displaces nutrient-rich topsoil that has been heavily tilled, resulting in diminished fertility and inability for plant communities to establish themselves.

A woodland ecosystem has been overbrowsed by moose that quite enjoy low-lying willow branches and seedlings, resulting in a depletion of young willow trees. Deer soon replace moose in the woodland to graze on the abundant grasses and sedges.

Boreal forests throughout Alaska and Canada are undergoing a transition where short-lived conifer stands are slowly replaced by deciduous hardwood stands, which are characteristic of a more mature forest.

Succession

Adaptation

Natural selection

Evolution

Mutation

Pre-existing nitrogen-fixing plant communities

Soil nutrients deposited by a nearby river

Wind-carried soil particles and nutrients

The time-consuming process of weathering the bedrock into smaller particles

Feces from wildlife populations that occupy the region

Lichen and grass communities establishing themselves on a recently-formed island, resulting from an uplift in the ocean bedrock

Native grass communities forming after a wildfire burned through a meadow/woodland ecosystem

Seedlings establishing themselves in a heavily logged area where the seed-tree cutting method was employed

Lichens re-establish themselves on rocks and shallow soil beds following a tundra fire

Coral reef and aquatic wildlife communities that have re-established themselves in regions of the South Pacific that were evacuated following the nuclear tests conducted by the U.S. military

Ecological succession

Climax community

Greenhouse effect

Pre-existing disturbance

Primary succession

Secondary succession

Pioneering succesion

Climax succession

None of these

Trees

Lichen

Moss

Grass

Secondary succession

Primary succession

Tertiary succession

Quaternary succession

Plant communities are established in a lifeless environment, usually devoid of soil

A transition from one ecosystem type to another

A succession of larger plants (trees, shrubs, etc.) following the establishment of pioneer species

A plant community becoming simplified with fewer species and less biomass

An ecosystem diversifying, supporting more species and increases in biomass