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19 Cards in this Set
- Front
- Back
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What is biodiversity?
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the variety of life. Biologists recognize and analyze biodiversity on three levels: genetic diversity, species richness and species diversity, and ecosystem diversity.
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What is genetic diversity?
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the total genetic information contained within all individuals of a species, measured as the number and relative frequency of all alleles present in a species.
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Species richness and species diversity?
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the variety of life-forms on Earth, measured as the number and relative frequency of species in a particular region
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What is ecosystem diversity?
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is the variety of biotic communities in a region, along with abiotic components such as soil, water, and nutrients. Attempts to measure ecosystem diversity focus on capturing the array of biotic communities and the variation of physical conditions in a region.
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What are the two general approaches to estimation the amout of species?
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1) surveys of species rich groups in small sites (taxon-specific surveys)
2)Surveys of all species present in a region. (all-taxa surveys) |
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What are hotspots?
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regions that are far more species rich than others.
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What is an endemic species?
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a species that is found in one region and no where else.
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What are conservation hotspots?
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hotspot regions where at least 1500 endemic species exist and 70% of the traditional or primary vegitation has been lost.
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When do scientists believe that the 6th major extinction will occur?
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they believe that it is now under way
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What are exotic species?
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nonnative competitors, preditors or diseases
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What are endangered species?
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species that are going to go estinct soon without active conservation groups.
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What did the analysis of causes for endangerment in canda conclude as the causes?
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1) Habitat distruction
2) over harvesting 3) Virtually all the endangered species are effected by more then one problem 4) Factors beyond human control may be a factor. |
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On a global scale what is the most important method of habitat destruction?
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deforestation, as many as 3 million hectares have been deforested every year.
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What is habitat fragmentation?
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the breakup of large contigous areas of natural habitat into small isolated pieces.
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What are the dangers of habitat fragmenation?
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The smaller pieces may not be able to support the species. The pieces may not be able to interbreed causeing them to creat metospecies in whic genetic diversity may accur along with inbreeding, depression and vunerablity to catastrophies.
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What are the two methods that scientists use to predict species extinction?
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1) Direct counts of extinct species.
2) Using species-area relationships to predict the consequences of habitat destruction |
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What is believed about the exinction rates of birds?
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They are much higher among birds, being about 1 species a year rather then the background rate of one every 100 years.
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What are species area curves?
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They are used to analyze the relationship between the species richness and habitiat area.
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What is the fuction that is used to calculate a species curve?
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S = cA^z
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