Ecological Succession

B 12.FDescribe how environmental change can impact ecosystem stability.B 11.D

DESCRIBE HOW EVENTS AND PROCESSES THAT OCCUR DURING ECOLOGICAL SUCCESSION CAN CHANGE POPULATIONS AND SPECIES DIVERSITY.

Ecological Succession

Gradual change in living communities that follows a disturbance.

Two types of succession

Primary successionSecondary succession

Primary succession

takes place in an area that is devoid of life — e.g., a lava flow, rocky mountaintop, or an area of land scraped clean by a glacier.

Primary Succession Characteristics

Pioneer organisms that require little or no soil (lichens and mosses) invade first.

As they grow and die, soil builds up and larger plants such as grasses can now grow.

The growing grasses shade out the lichen and moss communities, which die out.

The process continues with each community being replaced — bushes, small trees, and then larger trees

Primary Succession Primary Succession – occurs on surfaces where no soil

exists.

Primary Succession

Pioneer species - the first species to populate an area.

Example: After a volcanic eruption lichens grow on the rock helping to break it up.

When they die, their remains add organic matter to the soil.

Primary Succession

Primary Succession

Secondary Succession

Occurs following a disturbance that destroys a community without destroying the soil.

Secondary Succession

Certain plants have adapted to regular cycles of fire and re-growth. Their seeds won’t sprout unless exposed to fire.

Climax Community

A mature stable community that does not undergo further succession.

Pictureshttp://www.flickr.com/photos/59490522@N04/

Videohttp://www.youtube.com/watch?v=AQ8PlQW74EI&list=PL3792C3CB39C22B9C

Volcano - http://www.youtube.com/watch?v=2M5JQDdardM