1. HUMAN IMPACT
One-third of all plant and vertebrate species live on just 1.5% of Earth’s land
Every year, humans destroy an area of tropical rain forest equal to the size of West Virginia

2. Introduced Species Introduced species
#2 cause of extinction and loss of Earth’s biodiversity; border questions

3. Kudzu, a Japanese plant

4. HUMAN IMPACT ON ECOSYSTEMS
Burning of fossil fuels is the most likely cause of global warming

5. Impact on the Carbon Cycle
The increased use of fossil fuels
raises the level of CO2 in the atmosphere

6. Impact on the Nitrogen Cycle
Sewage treatment facilities and fertilizers
add large amounts of nitrogen and phosphates to aquatic systems, causing heavy growth of algae

7. Impact on the Water Cycle
Destruction of tropical rain forest
alters local and global weather patterns
the water cycle?

8. Deforestation and Chemical Cycles: A Case Study
The Hubbard Brook Experimental Forest is a study site for nutrient cycling in a forest ecosystem
Altered
Completion of tree cutting
Control

9. The Release of Toxic Chemicals to Ecosystems
Humans are adding new toxics to ecosystems and they often cannot be degraded by microorganisms

10. Biological magnification
DDT concentration increase of 10 million times
DDT in fish-eating birds
25 ppm
DDT in large fish
2 ppm
DDT in small fish
0.5 ppm
DDT in zooplankton
0.04 ppm
DDT in water
ppm

11. It was once thought that the atmosphere could absorb our gaseous waste products; smog

12. Depletion of Atmospheric Ozone
The ozone layer
absorbs UV radiation, preventing most of it from striking organisms in the biosphere
has nothing to do with global warming

13. Monthly averages for October
Our protective ozone layer
(a) Ozone hole
(b) Thickness of ozone layer
started thinning due to the build up of CFCs (chlorofluorocarbons)
Monthly averages for October

14. The consequences of ozone depletion
are quite severe for all life on Earth

15. The current mass extinction
The Loss of Species
The current mass extinction
caused by human activity
broader and faster than other past extinctions
boom and echo?
At the current rate of destruction over one half of all plant and animal species will be gone by the end of this century

16. The Three Main Causes of the Biodiversity Crisis
1. Human destruction of habitat; interaction?

17. Introduced Species
2. Introduced species

18. Overexploitation
3. Overexploitation of wildlife

19. Why Biodiversity Matters
Humans rely on biodiversity for
food, clothing, shelter
oxygen, soil fertility, medicinal substances

20. Conservation biology CONSERVATION BIOLOGY
a goal-oriented science that seeks to counter the loss of biodiversity

21. Biodiversity “Hot Spots”
A biodiversity hot spot
a relatively small area with an exceptional concentration of species

22. Equator
Tropical forest hot spots
Chaparral hot spots

23. Endemic species found nowhere else; common in hot spots
highly sensitive to habitat degradation

24. Conservation at the Species Level
Much of the discussion of the biodiversity crisis centers on species
The U.S. Endangered Species Act
an endangered species is “in danger of extinction throughout all or a significant portion of its range”

25. Conserving Species amid Conflicting Demands
Conservation biology
deals with relationships between biology and society
Competing demands for habitat are always an issue

26. Sustainable Development
balances human needs with the health of the biosphere
The goal of sustainable development
the long-term prosperity of human societies and the ecosystems that support them

27. Habitat Fragmentation
Population fragmentation
the splitting and consequent isolation of portions of populations by habitat destruction

28. Corridors A movement corridor
a narrow strip or series of small clumps of quality habitat connecting otherwise isolated populations
An artificial corridor

29. Corridors promote dispersal and help sustain populations
especially important to species that migrate between different habitats

30. Zoned Reserves A zoned reserve
an extensive region of land that includes one or more areas undisturbed by humans

31. The areas surrounding zoned reserves are buffer zones that support both agriculture and tourism