Ecological Succession 4-2 What Shapes an Ecosystem?

Ecosystems Change Ecosystems are constantly changing in response to natural and human disturbances. As an ecosystem changes, older inhabitants die out and new organisms move in. This is ecological succession.

Primary Succession Succession that occurs on surfaces where no soil exists. Occurs on the surfaces that are left bare after Volcanic eruptions Glaciers melting Pioneer species – the first species to populate an area Often lichens because they can grown on bare rock

Lichens

Primary Succession

Secondary Succession Change in an ecosystem after a disturbance (leaves soil behind) Examples: after wildfires, clear-cutting a forest, natural disasters Ecosystems usually recover from natural disasters, but may not always recover from long-term human disturbances.

Secondary Succession

Boreal Forest Biome - Succession