Transcript Disturbances Are Common In Communities

How Disturbances Can Have
Positive and Negative
Effects on Communities
Positive
• Water filtration
Negative
• Pollution
• Oil Spills
• Trees being killed
Primary and Secondary
Succession Comparison
Primary Succession Description:
The transformation of an ecosystem or
community from bare rock to a primary
forest.
Primary and Secondary
Succession Comparison
Secondary Succession Description:
When an existing community has been
cleared by some disturbance.
Primary and Secondary
Succession Comparison
Comparison Between The Two:
Primary is the building of a community and
secondary succession is when the community
is cleared out by a disturbance,
not creating a community but killing it off.
How Human Activities
Affect Species Diversity
• Over-exploitation, pollution and habitat conversion are the main
threats to species diversity.
• They cause a gradual loss of species on local, regional and
global levels.
• Additionally, the introduction of species into new ecosystems
destroys natural balance.
• The ever-growing tendencies of tourism, transport, profitoriented food production, and industry enforce these human
activities.
• Global warming and population growth continually increase
these pressures on biodiversity.
Bibliography
• Pic of oil-covered duck website:
http://www.wunderground.com/blog/JeffMasters/c
omment.html?entrynum=1483&tstamp=&page=4
&print=1
• Source 1: Biology book in science folder in
Novell
• Source 2:
http://www.biodiversity.ru/coastlearn/bioeng/boxes/specdiv.html