Evolution 1 Change in the inherited characteristics of biological populations over successive generations 2 Mutation change in genes random 3 Natural selection traits that are successful get passed on nonrandom Adaptation more functions 1 Specializations of a basic organ an organism possesses that performs 1 or a Central concept of evolution theory is that the various adaptations evolved from a common origin 2 Darwin s contribution a Proposed the concept of common ancestry for diverse organisms with obvious similar features i Evolutionary divergence increase the degree of difference b Large geographic distribution of life through time i Evidence 1 Large flightless birds different in America Europe Africa and Asia Isthmus of Panama Island species 2 3 4 Galapagos tortoise finches c Anatomical evidence in embryos in support of common ancestry for vertebrates d Homology e Vestigial organs i Similar structures hinting at common ancestor i Have a feature that no longer serves a purpose f Natural selection is the mechanism of evolution If a mutation occurs and isn t helpful it will go away i ii Survival of the fittest iii Traits that allow you to adapt to environment iv Artificial breeding why not natural breeding dog breeding v Requires 1 Survival of particular genetic traits 2 Production of offspring with particular genetic traits Speciation offspring 1 Darwin s Challenge How organism passes along favorable genetic trait to 2 Mendel s experiments lead to modern genetics a Punnet square b How genetics are passed on 3 Each parent contributes of genetic material 1 2 of its chromosomes 4 Genes are chemical structures that undergo chemical changes called 5 Speciation the origin of a new species from individuals of a preexisting a Branching event on a tree of life b Creates new reproductive barriers between preexisting species and c Often occurs as a result of spatial isolation of one population mutations species 6 Speciation event new species geographic Evolutionary Trends 1 Fossils a Rates of origination evolution and extinction b Evolutionary radiations point in time when degree of differences of an organism increases 2 Gradual 3 Rapid a Change in oyster bodies become flatter over time a Mutation b Genetic change in a regulatory gene 4 Both patterns have been documented from the fossil record 5 Fossils a Only direct evidence 6 Extinction a Predation b Disease c Competition d Change in physical conditions 7 High rates of extinction make useful index fossils time event markers 8 Mass extinctions a Often linked to a major environmental change b Can serve as an event marker bed c Earth history average extinction rate 1 extinction a day d 20 30 projected predictions several hundred species a day 9 Evolution is irreversible a Has directionality b Dollo s law evolutionary transition resulting from at least several genetic changes is unlikely to be reversed by subsequent evolution i Confirmed by analysis of fossil record ii Once a species is extinct it does not reappear
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