Evolution - EVOLUTION Study Guide(Gotta catch em all...

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EVOLUTION Study Guide (Gotta catch ‘em all?) Evolution - occurs on population level, variation is the raw material. We know a population is evolving when there are changes in allelic frequencies. Evidence: -Fossil record (past v. present), Direct Observation, Biogeography (distribution of organisms throughout the world, also explains Endemic species (found only in one place, usually islands)), and Homologies (anatomical and molecular (biochemical) Two Types: CONVERGENT (V): Two organisms that don’t share common ancestors evolving and looking or behaving similarly (possibly due to exposure to similar environments) (independent evolution of two similar looking species from different lineages) DIVERGENT(^): Two organisms that share a common ancestor evolving and looking or behaving differently from each other Charles Darwin - Theory of evolution: “Descent with modification”, driven by natural selection Descent with modification explains: Diversity and Unity of Life, and Adaptation to Environment. Adaptations - a heritable trait that increases one’s chances to survive and reproduce Fitness -ability to survive in an environment Allelic Frequencies -abundance of alleles in a population’s gene pool Natural Selection - occurs on individual level: “A process in which individuals with certain traits are favored to survive (more successful at survival and reproduction)” Acts upon VARIATION already found within the population (does NOT create anything new). Results in Differential Reproductive Success -Acts most directly on phenotypes -Indirect change in frequency of alleles of the whole population -Results in Adaptation to Environment (better fit between population and environment) -Charles Darwin based Natural Selection on observations: -Individuals in a population have heritable variation -Traits are passed from parents to offspring -Species produce more offspring than environment can support (Limited resources = lower survival rate) From
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