Lecture 24

Lecture 24 - Lecture 24: BIODIVERSITY! 1) How many species...

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Lecture 24: BIODIVERSITY! 1) How many species are living today? Aprox. 15 million species are categorized a. 2 general approaches a.i. surveys of species rich groups at small sites (taxa-specific survey) a.i.1. est. species richness via intensive local sampling a.i.2. from these data, est. that world total of arthropod species exceeds 30 million species a.i.3. based on such taxa-specific surveys, biologist est. that at least 1o million and possible as many as 10 million species of arthropods exist a.ii. survey of all the species present in a particular region (all taxa survey) a.ii.1. the first effort to fin and catalog all of the species present in a large area, the great smoky mt. 2) where is biodiversity highest? a. Tropical rainforests are species rich b. In most taxa groups, species richness is highest in the tropics and declines toward the poles c. Biogeographic factors c.i. Species richness declines along an equatorial polar gradient c.i.1. Tropical habitats support larger numbers of species than do temperate and polar region c.i.2. Exception: desert and Sahara in Africa= not species rich c.ii. Hotspots in terms of specie richness
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This note was uploaded on 01/23/2012 for the course BIO 106 taught by Professor Jeffreyjensen during the Fall '10 term at NYU.

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Lecture 24 - Lecture 24: BIODIVERSITY! 1) How many species...

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