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What was Easter Island (Austrilia) like when first found
In 1722, Small w/ little vegetation, Stone statues
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What was Easter Island Origonally like..
350 A.D fertile and densely forested. but by 1400 droped, 1550 forest gone..No food
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Loss Of Biodiversity...
15,000 people destroyed biodiverstiy which they depened on
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What is Biodiversty
Variety of life on in a particular habitat..or on earth
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Biodiversity today
6 billion ppl on planet, DECLINING biodiversity in the process of worldwide extinction..
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____ percent of all species that have ever lived on earth are now extinct
90
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Biodiversty is _____ than ever.
GREATER
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The current rage of biodiversity is the rusult of ...
Past extinctions and recoveries
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Mass Extinction... How many, and causes?
5 great mass extinctions, causes no always known
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What time periods where there mass extinctions..
- 1. Tertiary/Cretacequs
- 2. Triassic/permian
- 3. Carboniferous/Devonian
- 4. silurian/Ordovician
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______ recovers very slowly
Biodiverstiy
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Each mass extinction has been followed by an ________
Adaptive radiation
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it takes _____ million to ______ million years to reach pre-mass extinction level of diversity
20 million to 100 million
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___ million years ago human started hunting mammals
2
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about 11,000 years ago they began to drastically....
reduce mammalian habitat
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of 4500 living mammal species how many are endangered...
300
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Endemic?
species originated in one geographic region and found no where else..Extreamly vulnerable to extinction
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Habitat Loss because of what?
Chemical Pollution
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Habitat loss in US?
- 98% of tallgrass praries gone
- 50% of wetlands have been destroyed
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3 effects of habitat fragmentation
increases habitat edges, Decreases number of individuals that can be supported; may be too few to allow breeding, decreases the area in which individuals can find food or other resources
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Isolated patches of habitat are like...
Islands
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What is Island Biogeography?
Study of the factors affecting diversity on islands, implications for predictin extinction of nonisland species
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MacArthur-Wilson Model...
uses island biogeography to estimate future extictions
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what are some perdictions which the model has made?
- Destruction of 50 percent of habitat island will drive 10 percent of endemic species to extinction...
- Destruction of 90 percent of habitat will drive 50 percon of species to extinction
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Indicator Species?
species that provide warning of changes in habitat and impending widespread loss of biodiverstiy
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Exotic Species
intorduced into new habitat..Overcome endemic species, play role in why 70 of endmic species are threatened
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Threats to coral reefs
- Huricanes: Natural threats
- Manmade: water pollution, oil spills, dredging, dynamite, cyanide fishing, coral bleaching.
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reef- building corals have...
photosynthetic, dinoflagellate symbionts
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When doe corals expel protistans
when stressed
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if stress continues coral will die
leaving behind hard shell..Bleached Coral
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Conservation Biology
systematic study of biodiverstiy, works to decipher the evolutionary and ecological orgins of biodiverstiy, attempts to identify ways to maintain biodiversty for good of human pop
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Who is Rachel Carson
Silent Spring, 1962..Helped lanch the enviormental movement
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what is the main threat to biodiversity?
Human Growth
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When will people sustain biodivesity..
when they make a living doing so
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Strip logging?
sloped forested area is logged in strips, working p the slope
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Dodo Bird
First slighten around 1600, became extinct in 1681
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Tasmainian Tiger
Last known individual died at hobart zoo 1933
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Carolina Parakeet
Last seen in florida 1920
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Ivory-billed woodpecker
list confirmed sighting louisiana 1943
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The Great Auk
shot while nesting in iceland 1844, chicks too
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Tundra:
High latitudes, permafrost lies beneath surface, nutrient cycling very slow, no trees, cold open grasslands: ALASKAN TUNDRA
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Boreal Forest:
Taiga, Northern Europe, Asia, N. America, Cold dry winters, mild humid summers, spruce fir trees, birch and aspen, form islands in the southn app. mtns
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Temperate Deciduous Forest
Cool/Cold winters, warm rainy summers, Associated with Oak, Pine, Hickory, Maples... Eastern U.S, western Europe and much of Japan. Biome of Boone, NC
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Tropical Rain Forest:
Constant temp all year, heavy rainfall, distinct wet/dry season. 10 Degrees of equatior, broad leaf trees, vines, epiphytes, high biological productivity, very rapid nutrient cycling..West africa, malaysia, amazon basin
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Hot Deserts:
Winters are warm and dry, summers are very hot sporadic rain, little vegetation, southwest us, north africa, central austraila
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Chaparral:
Mediterranean Climate, cool rainy winters, hot dry summers, dense shrubs, grapes/olives. Many Fires!!
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Tropical Savanna
Warm Winters, hot summers, defined by wet/dry seasons, tall grasses w/ sporadic trees, Many large grazing mammals, Central Africa
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Temperate Grasslands
cold dry winters, warm wetter summer, shorter grasses and very few trees, Bison and Pronghorn, Central US
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