1. Ch. 10 Biodiversity

2. Section 10-1: What is Biodiversity?
Discussion Question: How do you define or describe biodiversity?

3. What is biodiversity?
Biodiversity – number of different species in a given area
Extinction – when last members of a species die
1.7 million known species (mostly insects)
Another 8 million estimated unknown species
-See the chart on page 259 for estimated numbers of species

4. Levels of diversity
Species diversity - number of different species (most studied)
Ecosystem diversity – variety of habitats, communities, and ecological processes within an ecosystem
Genetic diversity – all the different genes within a population

5. Benefits of Biodiversity
Healthy ecosystems depend on all of the species within them
Maintains balanced cycles of energy and nutrients
When too many species are taken from a food web it will collapse

6. Benefits of biodiversity, cont.
Keystone species – critical to maintaining balance within an ecosystem, disproportional role in the health of an ecosystem
Sea otter – eats sea urchins which eat kelp
Sea otter is hunted almost to extinction, sea urchins overpopulate, kelp beds are eaten away

7. More benefits Recreation Ethics Species and population survival
Ecotourism
Ethics
All species have a right to exist
Species and population survival
Genetic diversity within a species increases the chance that some individuals will survive environmental changes
When populations shrink, genetic diversity shrinks
Medical, industrial, agricultural use
¼ of prescribed drugs come from plants
Antibiotics come from fungi
Unknown uses for biological material
Food

8. Pharmaceutical Benefits
See Table 1 on p. 261 for a list of medicines derived from plants

9. Section 10-2: Risks to Biodiversity
Discussion Question: In what ways do humans cause a decrease the earth’s biodiversity?

10. Extinctions
Mass extinction – extinction of many species within a short period of time
65 million years ago: climate and environmental changes caused half of the species to die
Millions of years to rebound from mass extinctions
Current extinctions – we are in the midst of another mass extinction caused by humans
: 25% of species extinct (predicted)

11. Species prone to extinction
Species at risk –
small populations in small areas
migrating species
species that need large or special habitats
those exploited by humans
Endangered species – likely to become extinct if protective measures are not used
Threatened species – declining population that will likely become endangered without protective measures
See Table 3 on p. 264 for threatened and extinct species

12. How do humans cause extinctions?
1. Destruction of habitats – causes 75% of current
extinction
Habitat destroyed to build homes and to harvest resources
Florida panther – down to less than 100
Introduction of nonnative species – exotic species
threaten native species because they have no
natural defenses

13. How do humans cause extinctions?
3. Pollution – pesticides, cleaning agents, drugs are making their way into food webs
4. Overharvesting species – through hunting, harvesting, and poaching
Poaching – illegal hunting, fishing, harvesting and trading of wildlife

14. Areas of critical biodiversity
Areas with large portion of endemic species
(native to and found in limited area)
Tropical Rainforests – cover 7% of the earth and contain over half of world’s species

15. Areas of critical biodiversity
Coral Reefs and Coastal Ecosytems – small part
of marine environment but contain the majority of
species
Poorly studied and not well protected, high tourism
60% are threatened
serve as migration routes, thus provide link between aquatic and terrestrial ecosystems
Islands – very distinct species that have evolved
over time, not found anywhere else

16. Biodiversity Hotspots
Biodiversity hotspots: the most threatened areas of high species diversity
25 areas around the world: see figure 9 on p. 268
Most have lost 75% of original vegetation
Mostly tropical rainforests, coastal areas, and islands
Examples: Madagascar, Phillippines, New Zealand

17. Biodiversity in the United States
Wide variety of ecosystems
Florida Everglades, the CA coast, Hawaii, Midwestern prairies, forests of the Pacific Northwest
Unusually high numbers of freshwater fishes, mussels, snails, and crayfish
See Figure 10 on p. 269 for at-risk species in the US

18. Section 10-3: The Future of Biodiversity
Discussion Question: What are ways in which biodiversity is protected?

19. Ways to save species
1. Captive Breeding Programs – breeding in captivity and then reintroducing the population back into its natural habitat
Example: California Condor (read about on p. 270)
2. Preserving Genetic Material – storing germ plasm (genetic materials of plants and animals)
-use the germ plasm for future research
or species recovery efforts
-stored ad seeds, sperm, eggs, or pure
DNA
3. Zoos, Aquariums, Parks and Gardens – often house the last remaining individuals of a species
museums of the world’s biodiversity

20. Ways to save species Problems with these methods:
1. sometimes captive species don’t reproduce
2. small populations are vulnerable to genetic disorders from inbreeding
3. these methods should be a last resort

21. Preserving habitats and ecosystems
Most effective way is to preserve habitats which often means preserving large areas of land
But, some species live in very small habitats and could become extinct due to a single natural disaster

22. Preserving habitats and ecosystems
Conservation strategies
1. Protect entire ecosystems rather than individual species
2. Focus on world’s “hotspots”
More study needed
1. How large does a protected preserve have to be?
2. How much fragmentation can an ecosystem tolerate?

23. Legal Protections US Laws 1973 Endangered Species Act
Established list of threatened and endangered species
Protects any endangered species from human harm – guilty parties are fined
Prevents the govt. from carrying out any project that threatens an endangered species
Establish recovery plans

24. Legal Protections Recovery and Habitat Conservation Plans
Under the Endangered Species Act, a recovery plan must be prepared for each species
Controversial-usually compromises between human interests and species interests are made
Real-estate developers may be prohibited from building on a desired site that is habitat for an endangered species=loss of income and jobs
Habitat conservation plan – attempts to protect one or more species across large areas of land through trade-offs or cooperative agreements

25. International Cooperation
1. International Union for the Conservation of Nature and Natural Resources (IUCN): facilitates global efforts
2. International Trade and Poaching –
CITES Treaty – placed ban on trade of ivory stopping the slaughter of African elephants (began in the 1970’s)
successful
3. The Biodiversity Treaty –
Created in Earth Summit (held in 1992 in Rio de Janeiro, Brazil)
Preserve biodiversity and ensure the sustainable and fair use of genetic resources in all countries
Some political groups object to due to impact on trade agreements

26. International Cooperation
4. Private Conservation Efforts –
World Wildlife Fund:
Nature Conservancy:
Conservation International:
Greenpeace:

27. Balancing Human Needs
Humans sometimes are not concerned with the conservation of certain species because:
Sometimes endangered species are a food source or source of income
Species may not be valued or understood
Development of land for human use or economic use overrides the preservation of habitats