Transcript Ecological Succession Notes

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.
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You tube clip: http://www.youtube.com/watch?v=4-5kJmrLWRQ
http://www.youtube.com/watch?v=3eG_O1wEJ40