ecological succession notes. ecological succession ecosystems are constantly changing in response to...
TRANSCRIPT
Ecological Succession
Notes
Ecological Succession
• Ecosystems are constantly changing in response to natural and human disturbances.
• As an ecosystem changes, older inhabitants gradually die out and new organisms move in, causing further changes in the community.
Definitions• Ecological Succession – a
series of predictable changes that occur in a community over time.
• Includes - slow changes in the physical environment or sudden natural disturbances from human activities like clearing forests.
• Primary Succession – On land, succession that occurs on surfaces where no soil exists.
• Colonization of new sites by communities of organisms – takes place on bare rock
• Pioneer species – the first species to inhabit an area.
• Ex. Lichens are the first to colonize lava rocks
Primary Succession – Ex. #1• When volcanic
eruptions build new islands or cover land with lava rock or volcanic ash.
Primary Succession – Ex #2
• When bare rock is exposed as glaciers melt.
PRIMARY SUCCESSION
• Secondary Succession – when a disturbance of some kind changes an existing community without removing the soil – takes place on existing soil.
Secondary Succession – Ex. #1
• When land cleared and plowed for farming is abandoned.
Secondary Succession – Ex. #2
• When wildfires burn woodlands.
SECONDARY SUCCESSION
• Climax Community –a mature, stable community that undergoes little or no succession.
• Succession Clip and Mt. Saint Helens
• http://www.google.com/imgres?imgurl=http://www.darkfaery.com/
mount%2520st%2520helen%2520before%2520and%2520after.jpg&imgrefurl=http://www.darkfaery.com/Mount%2520St.%2520Helens.htm&usg=__yUnJj8r4wAXfOdGlLLJN7T8PM6w=&h=664&w=1065&sz=94&hl=en&start=4&itbs=1&tbnid=_tU5P1gCB42ZZM:&tbnh=94&tbnw=150&prev=/images%3Fq%3Dmount%2Bst.%2Bhelens%2Bbefore%2Band%2Bafter%26hl%3Den%26safe%3Dactive%26gbv%3D2%26tbs%3Disch:1
You tube clip: http://www.youtube.com/watch?v=4-5kJmrLWRQ
http://www.youtube.com/watch?v=3eG_O1wEJ40