BIOL 1107 1nd Edition Lecture 36 Outline of Current Lecture I Populations and Change II Variations III Pre zygotic and Post zygotic Mechanisms IV Speciation Outline of Current Lecture I Darwin and His Observations and Inferences II Evidence of Evolution III DNA Sequences Predictions Current Lecture I Darwin and His Observations and Inferences II Darwin s Observations o 1 Members of a population have varying traits not everyone was uniform o 2 When they reproduce they produce more offspring than the environment was capable of handling carrying capacity many failed to survive Darwin s Inferences o 1 Traits are able to survive and reproduce more offspring o 2 Uneven ability will leave more favorable traits in population o What is needed for descent with modification of a trait Variation in a trait in a population Trait must be heritable genetically controlled Differential survival and or reproduction ex having different colored fur is important in certain animals Evidence of Evolution Direct Observation These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute III o Scientists have directly observed evolution in many instances including the development of drug resistance in bacteria and other pathogens Homology can see similarities between certain species o Limbs of several species human cat whale bat o Homologies include similarities in structure development and DNA sequences in different organisms o Vestigial structures are homologous structures that have a reduced function or no function at all Examples include the pelvic bones of whales Snake vs lizard vestigial leftover fragments of femurs DNA Sequences Predictions Related organisms should have similar genes Mutations are random and accumulate The longer species are separate more differences Predictions o Organisms can be organized into phylogenetic family trees o Closely related organisms have more similar characteristics When different characteristics are examined give very similar phylogenetic trees Implication o All organisms share a common ancestor
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