3.3 Succession: How Ecosystems Change over Time

What is Succession? The predictable pattern of change in ecosystems is called succession. There are two forms of succession: primary & secondary succession

Primary Succession 1) Primary Succession – occurs in areas where no life exists due to absence of soil (eg. Volcanic islands). The succession begins with a pioneer species: lichen. _________ Species – typically the first organism to arrive to an area, helping to break down rocks into soil. Pioneer

What happens next??? Mosses, fungi, grasses, and herbs are next to establish themselves in the developing soil, followed by shallow rooted trees, until finally larger trees establish themselves creating a_______ community. _______ Community – is when diverse species develop into a stable, though still changing, ecosystem. (Fig. 3.9, pg 63). climax Climax

Primary Succession

Secondary Succession 2) Secondary Succession – occurs when a community has been destroyed or disturbed by natural occurrences or human activity (eg. A newly forested area or fire stricken area).

- The first species to appear in secondary succession are the wild grasses and weeds. The succession that follows mirrors that of primary succession.

Homework Check and reflect Page 64 #1-6