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Ecology (BIOL 250)
Lecture 25 : Species Loss and Conservation
- Practice questions for test on wed.
Biodiversity
"Number and variety of Earth’s organisms "Three components #Genetic diversity #Species richness #Ecosystem diversity Why Do We Need Biodiversity? "Ecological and agricultural processes "Food, medicines "Biological processes "Organisms are interdependent
Biodiversity Biodiversity - Ecosystem Services
"Environmental benefits provided by ecosystems "Often taken for granted "Species provide many medicines "Rosy periwinkle: childhood leukemia "AZT #Treat AIDS #Derived from a sea sponge
Biodiversity- Medicinal Value Extinction
"Natural event & ultimate fate of all species " 99 % of all previous species are extinct "But, currently accelerated by human activities #Estimated at 100-1000 times natural rate
Endangered & Threatened Species
"Endangered species #Threats that may lead to extinction #Numbers severely reduced "Threatened species #Declining population #Could become endangered "Genetic variability severely diminished
Where Is Biodiversity Declining?
"Tropical rain forests #Being destroyed faster than most other ecosystems #Disruptive effect on evolution: how? "United States #Hawaii #California
Human Causes Of Species Endangerment
"Habitat loss "Pollution "Invasive species "Overexploitation
Species endangerment - Habitat Loss
"Destruction, fragmentation, degradation "Largest threat to species "Why is so much land being altered? "Isolated patches often won’t do "Worldwide problem "Amphibians #Bellwether or sentinel species #Provide early warning signs "Many frog populations shrinking #Worldwide problem #Causes?
Species endangerment -
Disappearing Frogs
"Acid precipitation "Ozone depletion "Climate change "Direct or indirect poisoning "Altered habitat from chemicals
Species endangerment - Pollution
Reintroducing Species
"Ultimate goal of captive-breeding programs "One in ten successful: why? "Must determine #Why species was in trouble #If trouble will reoccur #If suitable habitat remains "Eg., Spotted owl vs. Barred owl
Seed Banks
"Seed collections " 100 + worldwide "Over 3 million samples "Kept at low temperatures "Disadvantages #Some can’t be stored #Expensive #Stopping natural selection
Endangered Species Act
"Legal protection to listed species "Endangered and threatened "Species get a plan for protection " 2005 : nearly 1300 species Critics Of The ESA "Limits property owners’ rights "Interferes with federally funded projects "Impediment to economic progress "Just keep adding more species
Endangered Species Act
Defenders Of The ESA "Many development cases reconciled "Has saved some species "ESA needs strengthening "Many species currently improving
Endangered Species Act
Future Of The ESA?
" Politically entangled since 1992 " Give property owners more rights? " Pay property owners for protection? " Protect whole ecosystems rather than single species?
Endangered Species Act
