CHAPTER 8 notes - Central case: saving the Siberian tiger o...

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CHAPTER 8 Central case: saving the Siberian tiger o Although tigers once roamed across Asia, today they are exceedingly rare and approaching extinction o Siberian tigers are the largest cat in the world The Russian Far East mountains house the last remaining Siberian tigers Historically, native people rarely killed tigers o Recently, the wild population approached extinction Hunting, poaching, and habitat destruction from road building, logging, and agriculture o International conservation groups are working to save the species from extinction Research, education, zoos, captive breeding programs Biodiversity encompasses several levels o Humans are diminishing earth’s diversity of life o Biodiversity= sum total of all organisms in an area Split into 3 specific levels: Species diversity Genetic diversity Ecosystem diversity Species diversity o Species diversity= the number or variety of species in the world or in a particular region Species richness= the number of species Evenness or relative abundance= extent to which numbers of individuals of different species are equal or skewed Speciation generates new species and adds to species richness Extinction reduces species richness o Taxonomists= scientists who classify species Common ancestry, ability to interbreed Genera= related species are grouped together Families= groups of genera o Every species has a 2 part scientific name: genus and species Subspecies: the level below species o Subspecies= populations of species that occur in different areas and differ slightly from each other
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Divergence stops short of separating the species Subspecies are denoted with a third part of the scientific name Genetic diversity o Encompasses the differences in DNA among individuals within species and populations o The raw material for adaptation to local conditions o Populations with higher genetic diversity can survive They can cope with environmental change o Populations with low genetic diversity are vulnerable To environmental damage Disease o Imbreeding depression= genetically similar parents mate and produce defective offspring Ecosystem diversity o Ecosystem diversity= the number and variety of ecosystems o It also encompasses differing communities and habitats Sizes, shapes, and interconnectedness of patches within habitats, communities, or ecosystems Some groups contain more species than others o Species are not evenly distributed among taxonomic groups Insects predominate over all other life forms 40% of all insects are beetles o Groups accumulate species by : Adaptive radiation Allopatric speciation Low rates of extinction Measuring biodiversity is not easy o Species richness is a good gauge for overall biodiversity o Out of out “best guess” estimates off 5-30 million species on earth, only 1.7-2million have been identified and described o Very difficult to identify species
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CHAPTER 8 notes - Central case: saving the Siberian tiger o...

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