Sustaining Biodiversity:
The Species Approach
Chapter 9
,Core Case Study: The Passenger Pigeon:
Gone Forever
Passenger pigeon hunted to extinction by 1900
Commercial hunters used a "stool pigeon”
Archeological record shows five mass
extinctions
Human activities: hastening more extinctions?
,9-1 What Role Do Humans Play in the
Premature Extinction of Species?
Concept 9-1A We are degrading and
destroying biodiversity in many parts of the
world, and these threats are increasing.
Concept 9-1B Species are becoming extinct
100 to 1,000 times faster than they were before
modern humans arrived on the earth (the
background rate), and by the end of this century,
the extinction rate is expected to be 10,000
times the background rate.
, Human Activities Are Destroying and
Degrading Biodiversity
Human activity has disturbed at least half of the
earth’s land surface
• Fills in wetlands
• Converts grasslands and forests to crop fields
and urban areas
Degraded aquatic biodiversity
The Species Approach
Chapter 9
,Core Case Study: The Passenger Pigeon:
Gone Forever
Passenger pigeon hunted to extinction by 1900
Commercial hunters used a "stool pigeon”
Archeological record shows five mass
extinctions
Human activities: hastening more extinctions?
,9-1 What Role Do Humans Play in the
Premature Extinction of Species?
Concept 9-1A We are degrading and
destroying biodiversity in many parts of the
world, and these threats are increasing.
Concept 9-1B Species are becoming extinct
100 to 1,000 times faster than they were before
modern humans arrived on the earth (the
background rate), and by the end of this century,
the extinction rate is expected to be 10,000
times the background rate.
, Human Activities Are Destroying and
Degrading Biodiversity
Human activity has disturbed at least half of the
earth’s land surface
• Fills in wetlands
• Converts grasslands and forests to crop fields
and urban areas
Degraded aquatic biodiversity
