Biology CH 18 Biology Vocab Tools A B Artidicial Selection organisms selected for specific traits Natural Selection mechanism that explains how populations evolve Mimiery mimcing appearence Camouflage structual adaption - allows animals to hide Homologous structure structures w/common evolutionary origin Analogous structure similar in function w/no common evolutionary origin Vestigial structure body structure w/reduced function that may have been earlier stage of species Gene pool sum of all genes amoung a population Speciation new species is formed Geographic isolation population isolated / no mating Reproductive isolation interbreeding organisms are prevented from producing offspring Gradualism idea - species orginate gradually over time through accumulation of small adaptive changes Punctuated equilibrium of speciation occur rapidly w/long periods of no speciation in between Divergent revolution once similar species Convergent evolution related to adaptions founder of modern evolutionary theory Charles Darwin Why Darwin was able to study so many different organisms Voyage on Beagle for about 5yrs. Galapagos islands and their importance West coast of SA - suport great animal/plant diversity Darwin's Book On the Origin of species by natural selection - 1859 excamples of structual adaptions mimicry/camouflage excamples of physiological adaptions penecilian/pestasides how fossils are evidence of evolution scientists can understand general pathway of evolution homologous structures are evidence of evolution by vertabres moving into different enviroments vestigial structures are evidence of of evolution reduce function/once used by esential organisms how embryological development is evidence of evolution similarities amoung vertabrate embryos suggest evolution from common ansestor genetic comparisons are evidence DNA studies reveal whn species diversed how artificial breeding is evidence of evolution shows interperting relationships mutations importance adds new genetic material to gene pool stablizing favors average directional both at a selected average disruptive both extremes favored puntuated species occurs in rapid burst gradualism species originate by gradual build of new adaptions