Aim: How do ecosystems change over time?

Ecological Succession1 The process by which an ecosystem changes over time – often from a barren piece of land to a complex ecological community (depending on climate) 1 2 3 4 5

Ecological Succession In a Forest As time passes grasses grow & then get replaced by shrubs and eventually a forest will form. Why do the grasses disappear? The large shrubs and trees prevent light from reaching the grasses.

Ecological Succession in Ponds & Lakes: As time progresses, the pond gets filled in with dead organic matter. The dead organic matter takes the place of the water in the pond or lake. Eventually (through succession) a forest may form where the pond once was.

What is the final state of ecological succession A climax community with great biodiversity

Plant adaptation / succession 1:48

Destruction of Climax Communities Fires, volcanic eruptions, tsunamis, deforestation, acid rain. Their destruction often (but not always) means the birth of a NEW community via succession.

Are forest fires an ecosystems worst nightmare? Why or why not?

Fire in the Forest 2:25

Soil Formation: Lichens (fungus and green algae) & weather break down rock into its minerals. Dead Organic materials are added to the minerals

Maintaining Soil: The plant roots hold on to the soil & prevent erosion (washing away of valuable material). How could erosion cause a problem for an ecosystem?