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Unformatted text preview: Biology 1107 Lecture #40 Biology April 19, 2010 Evidences of evolution Evidences Continental drift Fossil record Comparative anatomy Comparative embryology Molecular biology Domestication(artificial selection) Experiments Continental Drift Fossil record in Sedimentary Rock Fossil Formation Fossil Fossils of extinct organisms Fossils Transitional fossils Archeopterix Archeopterix Archeopterix Archeopterix Comparative Anatomy Homologous Structures Comparative Co Homologous structures - mammals Homologous . To say that two structures are homologous means that they are derived from a common ancestor and that the feature was present in that common ancestor. Whale vestigial pelvis Whale Vestigial organs - whale pelvis Vestigial Vestigial organs Whale pelvis Evolution of the elephant Evolution Comparative embryology Comparative Molecular homology homology Diverse vegetables derived from wild mustard mustard Domestication – Artificial Selection Molecular Homology Molecular Humans and Chimps Chimps have >99% have similarity in DNA. similarity Human 46 chromosomes Human Chimp 48 chromosomes Chromosome #2 in humans Chromosome is a result of fusion of two chimp chromosomes. Human chromosome 2 has telomere DNA where the two chromosomes have fused. fused. Human/Chimp Chromosomes Human/Chimp Convergent evolution Convergent Concept 23.2 Concept The Hardy-Weinberg equation can be used The to test whether a population is evolving. to Hardy- Weinberg law of genetic equilibrium equilibrium The allele frequency in a population will remain constant if: if: The population is large There are no mutations Mating is random No gene flow (no immigration No or emigration) or For a change in allele frequency, one or more of the H/W conditions are not operating not Hardy-Weinberg Nature Large Usually small Large population population Mutations are Mutations frequent frequent No mutations Mate selection Random mating Immigration, Immigration, No gene flow emigration emigration Five forces that can change allele frequency in a population allele Mutation Gene flow Genetic Drift Non random mating Natural selection Genetic Drift Genetic Loss of an allele in a small population population ...
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