01 Evolution - B i ol ogi cal Di ver si ty Beetl es Rock!

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Unformatted text preview: B i ol ogi cal Di ver si ty Beetl es Rock! Bacteria.................................................. 4,000 Protoctists (algae, protozoa, etc.)......... 80,000 Animals, vertebrates............................. 52,000 Animals, invertebrates..................... 1,272,000 Fungi.................................................... 72,000 Plants.................................................. 270,000 Total number of described species... 1,750,000 ~385,000 Speci es of Beetl es T he Two Uni fyi ng Theor i es of Bi ol ogy • Cel l T heor y L i vi ng or gani sms ar e composed of cel l s Al l cel l s onl y ar i se fr om other cel l s • T heor y of Evol uti on The geneti c composi ti on of or gani sms changes over ti me The pr i mar y agent of change i s N atur al Sel ecti on N atur al Sel ecti on • Ther e i s geneti c var i ati on i n the popul ati on that ar i ses f r om mutati on and, i n sexual l y r epr oduci ng popul ati ons, geneti c r ecombi nati on • I n any par ti cul ar bi oti c and physi cal envi r onment some i ndi vi dual s wi l l be mor e successful at pr oduci ng offspr i ng than other i ndi vi dual s. Thus over ti me, genes t hat gener ate r epr oducti vel y successful phenotypes wi l l become mor e pr eval ent i n the gene pool of the popul ati on. I f sel ecti ve pr essur e i s str ong, evol uti on can be qui te r api d Evol uti on of H I V Resi stance The dr ug, 3TC, i nter fer es w i th the enzyme that m edi ates the i ncor por ati on of the vi r al RNA i nto the D NA of the human host cel l (r ever se tr anscr i ptase). Some H I V car r y a mutati on i n r ever se tr anscr i ptase that i s unaffected by 3TC. Thi s var i ant i s r api dl y sel ected f or i n pati ents taki ng 3TC. A r ti fi ci al Sel ecti on: Wi l d M ustar d i s the “common ancestor ” for a wi de var i ety of common vegetabl es that ar ose fr om ar ti fi ci al sel ecti on for speci fi c tr ai ts. Phyl ogeneti c Tr ee Der i ved fr om anal ysi s of the sequence of h edgehog, a devel opmental gene E vol uti on at the M ol ecul ar L evel Because evol uti on i s “ conser vati ve” i t i s often possi bl e t o der i ve gener al pr i nci pl es of bi ol ogi cal or gani zati on fr om the study of onl y a few or gani sms. F or exampl e, al though the mouse and the human have fol l owed separ ate l i neages for the past 65 M i l l i on year s, thei r hemogl obi n m ol ecul es ar e 87% i denti cal . T i mi ng of the Dai l y Sl eep/ Wake Cycl e Awake Our under standi ng of the m ol ecul ar basi s of the sl eep/ wake cycl e i n Awake h umans or i gi nated wi th studi es on the r egul ati on of the acti vi ty/ r est cycl e i n f r ui t fl i es. Thi s has l ed, for exampl e, to the di scover y t hat an i nher i ted type of i nsomni a i n humans “advanced sleep phase syndrome” i s now known “ Asl eep” t o be caused by a mutati on i n a gene or i gi nal l y d i scover ed i n fl i es (the per i od gene) whi ch r egul ates how fast our bi ol ogi cal cl ock r uns. Asl eep Si gnal i ng i n the Ner vous System Our under standi ng of how ner ve cel l s gener ate el ectr i cal si gnal s (Acti on Potenti al s) that ar e used i n the human br ai n or i gi nated wi th studi es on a “gi ant” n eur on i n the squi d. L ear ni ng and M emor y Our under standi ng of the basi c m echani sms by whi ch memor i es ar e for med and stor ed i n the n er vous system have emer ged f r om studi es on l ear ni ng and m emor y i n the mar i ne sl ug A pl ysi a (the Sea H ar e). Ter r estr i al H ar e ...
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This note was uploaded on 11/12/2010 for the course BSCI BSCI 110B taught by Professor Johnson during the Spring '09 term at Vanderbilt.

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