Chapter 38 - Introduction SavingtheTiger A Focus on the...

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Chapter 38 Lecture Outline Introduction Saving the Tiger A. Focus on the human destruction of habitat and conservation efforts in the struggle to save the tigers. 1. The tiger population was estimated to be around 100,000 worldwide 100 years ago. There are now approximately 5,000 remaining, and 3 of the 8 species are extinct. 2. Intense conservation efforts by the government of Myanmar have begun to save the tiger population in the Hukawng Valley. Estimates from 2001 placed the tiger population in the 6,500 sq. km reserve at 150 to 200. 3. The Myanmar government increased the reserve size to 20,000 sq. km to provide more habitat for the tiger and its prey. Wildlife biologists hope to see a tenfold increase in the tiger population in the next decade. B. The story of the tiger illustrates the biodiversity crisis (a rapid decrease in plant and animal diversity) that is threatening life on Earth. C. Conservation biology is an attempt by biologists to reverse the destructive trends of habitat and species destruction. The approach can be on a single species, as with the tiger, or very broad, attempting to assess and protect many species at once. D. This chapter focuses on the biodiversity crisis and approaches used by conservation biologists to slow the loss of species. Conservation biology touches all levels of ecology, from a single species (the tiger) to the habitat in which it lives (the Hukawng Valley reserve). I. The Biodiversity Crisis: An Overview Module 38.1 Human activities threaten Earth’s biodiversity. A. The high rate of species loss is a direct result of human activity. Humans are altering trophic structure, energy flow, chemical recycling, and natural disturbances. B. There are approximately 10 million to as many as 80 million different species in the world. Scientists have named about 1.5 million species. The rate of species loss is estimated to be 1,000 times higher than at any time in the past 100,000 years. C. Biodiversity has three components: genetic, species, and ecosystem diversity. 1. Genetic diversity within and among populations of a species is dependent on the raw material provided by the genes. If a population is lost, there is a reduction in the available material used for adaptation to environmental changes. Extreme decreases in genetic diversity endanger the survival of a species. 2. Species diversity is the variety of species in an ecosystem and is a popular scientific, as well as political, topic. The ESA defines an endangered species as one that is close to extinction in all or most of its range. The ESA also defines threatened species as those that are close to becoming endangered in the near future. 3. Ecosystem diversity is described as the interaction of populations of different species within an ecosystem. Removal (extinction) of a species in an ecosystem can adversely affect the
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remaining species, particularly if the lost species is a keystone predator like the tiger. Altered patterns of chemical and energy flow in one ecosystem can affect the entire
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This note was uploaded on 03/10/2011 for the course BIOL 10 taught by Professor Kite during the Spring '11 term at Laney College.

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Chapter 38 - Introduction SavingtheTiger A Focus on the...

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