Lecture_15_Biodiversity_and_Conservation

Lecture_15_Biodiversity_and_Conservation - 6/15/2011...

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6/15/2011 1 Biodiversity and Conservation LS1: Summer Session A July 29, 2011 Conservation Biology Conservation biology is an applied science, with the goal of protecting and managing the biodiversity of the earth Biodiversity, in this context, can refer to: Genetic variation Species richness Ecosystem diversity Extinctions are a part of life Background extinction rate = 10% per million years Mass extinctions involve the loss of many species in many habitats Five major mass extinction events in earth’s history, caused by global changes Human impacts on extinction Human activities can have significant impacts on biodiversity. When humans first arrived in North America 14,000 years ago, most of the megafauna went extinct within a few thousand years. The value of biodiversity Ecosystem services Direct human benefits, such as food and medicines Aesthetic benefits Opportunities to study ecological relationships Ethical considerations of nature Direct benefits Plants and animals provide sources for many medicines
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6/15/2011 2 Wild organisms provide genetic diversity we can utilize Domestic corn (annual) hybridized with teosinte (perennial). Genetic modification of strawberries. Ecosystem services Ecosystems provide oxygen, sequester carbon, fix nitrogen, filter water, prevent floods, and control erosion Breathe in. Breathe out. Thank the Amazon for the oxygen. Intrinsic worth Pretty. Measuring changes in biodiversity It is often difficult to assess changes in biodiversity, because our knowledge of biodiversity is incomplete Predicting impacts on biodiversity Predictive statistical models, using the theory of island biogeogrpahy, can be applied to infer biodiversity loss Habitat loss can be directly measured Reductions in population or habitat size can jeopardize species persistence Human Impacts on Biodiversity The sixth great mass extinction Current extinction rate is 1000x background (thousands per year) Caused by the effects of humans Habitat loss or damage Introduced species Overexploitation Climate change
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6/15/2011 3 Status of species in the U.S. Habitat destruction The most important threat to biodiversity worldwide Increasing as a result of human population growth (demands for food, fuel, real estate) A clear-cut forest, Oregon Deforestation in the Amazon Basin Amazon deforestation Farmland Grazing Logging The Aral Sea Soviet-era irrigation projects diverted millions of cubic meters of water from rivers that fed the
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Lecture_15_Biodiversity_and_Conservation - 6/15/2011...

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