BIOB 272 1st Edition Lecture 1Outline of Last Lecture I. Syllabus ReviewOutline of Current Lecture I. Intro to EvoluitonA. Define Biological EvolutionB. Evolution misconceptions II. Evolution Case Study: Whales Evolutiona.Whale synapomorphies and homologous features to other cetaceansb.Whale Fossil Timelinec.Evidence of Fossil Evolution of WhalesCurrent Lecture1/28/15Genetics and Evolution (BIOB 272) Lecture 2:Biological Evolution: any change in the inherited traits of a population that occurs from one generation to the next- Process by which populations change over time- Study of history of life and the process that led to its diversity- Based on adaptation, change and historyMisconceptions about evolution:1. It’s “just” a theory-theories are the ultimate GOAL of science2. Central goal is to explain origin of life- it actually deals with how life has changed after it originated- other sciences try to explain origin of life3. Evolution is nature selection-natural selection is a mechanism of evolutionary change- other mechanisms: genetic drift, sexual selection 4. Evolution is entirely randomThese 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.-mutations are random-natural selection is not random, but actually a non-random spread of mutations 5. Evoultion is a march or progress (like the famous picture of apes to humans)-NOT ladder like march- instead a huge branching patternEvolution Case Studies:1.Whales:- Shared unique characters with other mammals: (synapomorphies)o Mammary glandso 3 middle ear boneso hair (in developing embryos) - Homologous structures: shared ancestry traits in 2 species - Analogous Structures: similar structures developed through convergent evolution- (i.e whales & fish fins)- Whale evolution: a gradual transition from land to aquatic environmentso To determine evolution, used whale-specific synapomorphies= characteristics found onlyin cetaceans (i.e. structure of inner ear, skull)Whale Fossil Timeline:50 MYA: Pakicetus-first terrestrial cetacean -found fossil in Pakistan-fossil conditions suggest they lived in hot dry conditions with seasonal water-evidence shows was able to walk on land and not marine animals45 MYA: AmbulocetusNatans-“walking whale”-could walk, but closer to aquatic40 MYA:Dorudon, first robust whale fossil38 MYA: Basilosaurusisis-vestigial structures: loss of most or all of ancestral form-evolved to marine animalsEvidence of evolution of Whales to marine animals:1. Isotopic analysis of fossil teeth:-Terrestrial animals drink freshwater-Marine animals drink saltwater-O18/O16 ratio higher in saltwater and in teeth of marine animals 2. Changes in gene expression during development led to hindlimb loss -dolphin limb development= 4-9th week of embryonic development -hindlimb only started to develop, but did not completely formWhales most closely related to Hippos-Similar DNA -Similar shape of astragulus (specific ankle
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