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, profit-oriented 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/comment.html?entrynum=1483&tstamp=&page=4&print=1

• Source 1: Biology book in science folder in Novell

• Source 2: http://www.biodiversity.ru/coastlearn/bio-eng/boxes/specdiv.html