Intro to anatomy
Intro to comparative anatomy \n \n Basic Definitions \n Anatomy from the Greek word temnein ‘to cut’Identifying and describing body partsMorphology Study of forms and functionPaleontologyStudy of prehistoric life, based on fossilsHeavy focus on skeletal systemFunctional AdaptationWhen genes change over time to adapt to a particular environmentComparative MorphologyAnalysis of the patterns of the locus of structures within the body plan of an organismForms the basis of taxonomic categorizationHomology (Shared ancestry)  Common ancestrySame embryonic precursorBones of fingers and bones of horse leg are similarAnalogy (Shared function)Insect wings and bird wingsHorns on cows and horn on a rhinocerosGills and lungsNot a common ancestry, necessarilyHomoplasy (Shared anatomy)Shared anatomyNot homologousNo common ancestryInsect wings and leaves Function, then formDarwin’s theory of Natural SelectionAdaptationForm, then functionPreadaptationLimbs first, then you go out on landFeather first, then flyEvolutionRandom chance mutations, coupled with geographic isolation leads to…Change in gene frequency in a populationDivergent EvolutionRelatedPresent species evolved from common ancestorConvergent evolutionNot closely relatedDissimilar features evolved to become similar featuresBats and birds both fly - not close ancestors! Parallel evolutionRelated and isolatedCorresponding features undergo equivalent changes in isolated environmentVestigial structureLeftover from previous structureBetter developed in ancestorE.g. pelvic girdle in python, appendixRudimentary structureMore developed in descendantE.g. neck, earOntogenyIndividual’s life historyFertilization to deathInfluenced by environment and geneticsHeterochrony: change to the timing or rate of developmental events, relative to the same events in the ancestor. Paedogenesis (peedo-genesis)Gonads develop quicklyBeneficial for animals that are sessile later in lifePaedomorphosisImmature features of ancestor become permanent adult features of future SPECIESExternal gills in necturus (mud puppy)NeotenyImmature features are retained as an adult in the INDIVIDUAL \n \n Vertebrate characteristics  Chordata characteristicsDorsal hollow nerve cordSpinal cord in more advanced animalsFull of fluidNotochordPharyngeal gill slits/archesTemporary but still present in land animals+/- postanal tail |
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