BIO370lecture2 - The Dive rs ity o f Life , E.O . Wils o n...

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Unformatted text preview: The Dive rs ity o f Life , E.O . Wils o n ~ 5-10 m illio n s pe c ie s , o nly 1.5 m illio n na m e d http://www.s p2000.o rg / Lecture 2 Diversity changes through time ! Burgess Shale fossils Ma rine a nim a l fa m ilie s thro ug h g e o lo g ic a l pe rio ds C ha ng e s in dive rs ity thro ug h tim e Mo llus c a Ec hino de rm a ta C ha ng e s in dive rs ity thro ug h tim e Trilobites Changes in form through time Trilo b ite rib s o ve r 3-m illio n ye a r s tra tig ra phic s e c tio n C ha ng e s in fo rm thro ug h tim e S tic kle b a c k m o rpho lo g y o ve r 110,000 yrs g ra dua l a nd punc tua te d c ha ng e ! C ha ng e s in fo rm thro ug h tim e Extinc tio n e ve nts fre q ue nt a t le a s t five b ig g ie s O f the s pe c ie s tha t ha ve e xis te d, 99% e xtinc t Comet Shoemaker-Levy strikes Jupiter, 1994 Why do species look and behave the way they do? Birds o f Pa ra dis e , Pa ra dis a e ida e Pha s m ida , s tic k a nd le a f ins e c ts Jean Baptiste Lamarck (1744-1829) Philosophie Zoologique (1809) inheritance of acquired characters Environmental change generates new needs Needs determine the use or disuse of organs Such organs develop or diminish The acquired characters are hereditary Natura l S e le c tio n Diffe re ntial s urvival & re pro duc tio n Basic argument of evolution by natural selection Organisms produce more offspring than can survive Populations are constant over long periods due to food & space limitations Many individuals die before reproducing and leave no or few offspring Basic argument of evolution by natural selection Individuals show variation in the ability to survive Those that survive and reproduce must have a slight advantage, a favorable variation Some variations are heritable/genetic, they pass on to the next generation Over many generations, natural selection among genetically variable individuals results in genetic changes in populations The FIRST predictive frameworks for understanding diversity! Angraecum sesquipdale Xanthopan morganii predicta Observations: Life is old 3.5-4 billions years.Life is old 3....
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BIO370lecture2 - The Dive rs ity o f Life , E.O . Wils o n...

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