How Ecosystems Change Ecosystems are changing constantly Ecological

How Ecosystems Change Ecosystems are changing constantly

Ecological Succession • The gradual process of change and replacement of some or all of the species in a community. – May take 100 s to 1000 s of years

Ecological Succession Key Terms • Pioneer species – the 1 st organism to colonize any newly available area and begin succession. The pioneer species will make the new area habitable over time. (Ex: moss, weeds, bacteria, fungi) • Climax community – final, stable community that will remain the same through time if not disturbed. (Ex: mature hardwood trees)

Think – Pair - Share • Imagine that on your graduation day the school is bulldozed and a tall fence is placed around the bare school grounds. – What would the school grounds look like after: • 1 month? • 1 year? • 5 years? • 100 years? http: //www. youtube. com/watch? v=AWwe 0 udew. D 8

Primary Succession • Succession that occurs on a surface where no ecosystem existed before

Primary Succession • Where? – Places without soil • • Rocks New islands created by volcanic eruptions Areas exposed when glaciers retreat Other surfaces that had not previously supported life (parking lot)

Primary Succession • Pioneer species? – Lichen or bacteria on a rock (eventually they will break down the rock to make soil). – Mosses, lichens, and weeds in pavement cracks or an uncared for roof.

PRIMARY SUCCESSION

Think – Pair - Share • How does the pioneer species lichen help to make primary succession possible?

Secondary Succession • Succession that occurs on a surface where an ecosystem has previously existed. Ex: occurs on ecosystems that have been disturbed or destroyed

Secondary Succession • Where? – Ecosystems disturbed by humans and animals – Ecosystems destroyed by storms, floods, fires, earthquakes, and volcanic eruptions. • Ex: Mt. St. Helens erupted in 1980, burning and flattening more than 44, 460 acres of forest. Over time, plants that began to grow over the volcanic debris. Immediately after Mt. St. Helen 12 years after the eruption

Secondary Succession • Pioneer Species? – Annual plants and flowers – Grasses and weeds

SECONDARY SUCCESSION

Secondary Succession • Old-Field Succession – occurs when farmland is abandoned. – Abandoned land changes into grassland, then shrubs, then young trees, then mature trees.

Think – Pair - Share • Over a period of 1000 years, a lake becomes a maple forest. Is this process primary or secondary succession? Explain.