Robert Haseltine Last ap summer homework - Robert Haseltine AP 3 Summer Homework Notes and Vocab 100 years ago there was about 100,000 tigers that could

Robert Haseltine Last ap summer homework - Robert Haseltine...

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Robert Haseltine AP 3 Summer Homework Notes and Vocab: 100 years ago there was about 100,000 tigers that could be found in the wild, now there is only about 5,000. Three of the world’s eight tiger subspecies have disappeared entirely. They still live in 14 Asian countries today. Tiger bones have sold for as much as $200 per kilogram on the black market. Officials in Myanmar turned a 6,500 square kilometer lot into a reserve to protect the tigers. The land soon expanded to 20,000 kilometers. Biodiversity: The variety of living things. Biodiversity crisis: A rapid decrease in Earth’s great diversity of organisms. Conservation biology: A goal-oriented science that seeks to counter the biodiversity crisis. Today scientists have described and formally named about 1.8 million species. Some believe the real number may be up to about 10 million though. Biophilia: Our sense of connection to nature and other forms of life. In the U.S. 25% of all prescriptions dispensed from pharmacies contain substances derived from plants. When species are lost, so are their unique genes. Biodiversity has three levels: Genetic diversity, Species Diversity, and Ecosystem Diversity. Endangered species: Species that are in danger of extinction throughout all or a significant portion of its range. Threatened species: Those that are likely to become endangered in the foreseeable future. Global extinction means that the species has been lost from all the ecosystems in which it lived. About 12% pf 9,934 known bird species and 20% of the 5, 416 known mammalian species in the world are threatened with extinction. About 20% of the known freshwater fishes in the world have either become extinct during historical times of are seriously threatened. About 32% of all known amphibian species are either near extinction or endangered. Of the approximately 20,000 known plant species in the United States, 200 species have become extinct since dependable records have been kept, and 730 species are endangered or threatened. Human alteration of habits poses the single greatest threat to biodiversity throughout the biosphere. Human-altered land surface is around 50%, and we use over 50% of all accessible fresh water.
Habitat destruction is implicated in 73% of the species in modern history that have become extinct or endangered. A brown tree snake got on the Pacific Island of Guam by a plane, and cause many species to either become extinct or very close. Those that survived are now being protected in zoos. Overexploitation of wildlife by harvesting at rates that exceed the ability of populations to rebound is a great threat to biodiversity. Humans also aid in the biodiversity crisis by releasing harmful pollutants.

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