Lecture 2 - Bio 121 Lecture 2 A. How many species a. 1.8...

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Bio 121 Lecture 2 A. How many species a. 1.8 million are named/identified (thousands added per year – most insects) b. Absolute diversity (if we could name everything) estimated around 18 million c. Estimated only 25% of bacteria known in a fecal sample d. ½ living species live =< 6% of land (mainly tropical forest (1 acre/minute destruction) d.i. Leading to extinction – about 100 to 100x normal rate of extinction d.ii. Leads to loss of genetic library e. Argued reasons to conserve biological diversity e.i. Moral/ethical approach – humans are part of biosphere(every extinction hurts humans somehow) e.ii. Greed/self-interest - economic opportunities/ health/ pharmaceuticals/ tourism e.iii. Free market approach – resources reflect true value to society. Hard to tell price/value of biodiversity. B. Classifying life a. Systematics – studies the evolutionary and genetic relationships among organisms a.i. Encompasses taxonomy – branch of bio that deals with naming/classifying of organism according to a formal scheme a.ii. Construct tree of life a.ii.1. Linnaen hierarchy (Kingdom, phylum, class, order, family, genius, species (king Phillip came over for great sex) a.ii.2. Reflects evolutionary history (phylogenetic tree – graphical representation of evolutionary history of speices based on similarities and differences) a.ii.3. Scientists can use biochemistry, ecology, morphology C. Molecular Phylogeny (used to determine evolutionary relationships)
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This note was uploaded on 03/12/2012 for the course BIO 121 taught by Professor Minchella during the Fall '10 term at Purdue University-West Lafayette.

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Lecture 2 - Bio 121 Lecture 2 A. How many species a. 1.8...

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