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Biodiversity in Crisis, p.5 ( n.b .) Jan . 16, 2013 ( Periods 1, 3, 5)

Bi 6a. Biodiversity in Crisis, p.5 ( n.b .) Jan . 16, 2013 ( Periods 1, 3, 5). Biodiversity in crisis. the diversity of nature cannot support the current pressure that humanity is placing on the planet. ( human activity decreases biodiversity)

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Biodiversity in Crisis, p.5 ( n.b .) Jan . 16, 2013 ( Periods 1, 3, 5)

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  1. Bi 6a Biodiversity in Crisis, p.5 (n.b.)Jan. 16, 2013 ( Periods 1, 3, 5) Biodiversity.ppt

  2. Biodiversity in crisis • the diversity of nature cannot support the current pressure that humanity is placing on the planet. ( human activity decreases biodiversity) • 70% of coral reefs are threatened or destroyed. • 18,788 species out of 52,017 so far assessed are threatened with extinction. • 1,895 of the planet’s 6,285 amphibians are in danger of extinction, making them the most threatened group of species known to date. Biodiversity.ppt

  3. Threat #1:Habitat Destruction • Deforestation -> forests are cut down for human use—ex. Agriculture, cattle-grazing, housing • Urbanization -> beaches, marshes, mountains are replaced by housing, hotels, golf-courses etc. Biodiversity.ppt

  4. Threat #2:Overexploitation • Hunting -> Elephants for Ivory -> Tigers for pelt -> Bears for medicine • Overfishing • Tuna, Sharks, Other large fish • Whaling/ Dolphin Hunting Biodiversity.ppt

  5. Threat #3: Alteration in ecosystem composition/changing networks Ex. Eliminating coyotes in Southern California->decrease in bird population Normal Food Web: Bird eggs->raccoon-> coyote No coyote to control the raccoons who will then eat more bird eggs. Biodiversity.ppt

  6. Threat#4: Non-native species( Invasive, foreign , exotic) Ex. Brown tree snakes were brought into Guam through planes and ships. Snakes have no natural predator in Guam so they reproduced without control. Biodiversity.ppt

  7. Brown Tree Snake • Brown Tree Snakes introduced to Guam in the 1950s. In less than 20 years they decimated bird, bat and lizard populations. • •On Guam--Caused one power outage every four days Biodiversity.ppt

  8. Threat #5 Pollution/Global Warming • Pollution-> affects all levels of biodiversity • Global climate change-> changes environmental conditions. Species and population may be lost if they are unable to adapt to new conditions or relocate Biodiversity.ppt

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