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Published byMatthew Griffith Modified over 9 years ago
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BIO 3220 COMPARATIVE VERTEBRATE ANATOMY Thank you to McGraw-Hill and Dr. Anil Rao (MSCD) for use of PowerPoint illustrations
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Basic Definitions Anatomy Morphology
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Phylogeny – Evolutionary History Paleontology Functional Adaptation Comparative Morphology Embryology
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Homology Shared common ancestry Same embryonic precursor
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Analogy Shared function Insect wings & bird wings Gills & lungs
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Homoplasy/Homoplastic Organs Shared anatomy Generally, not homologous E.g. Insect wings vs. leaf
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Key Points Homology Analogy Homoplasy
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Form vs. Function Function, then form – Darwin’s Theory of Natural Selection – Adaptation Form, then function – Preadaptation
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Evolution Random chance mutations, coupled with geographic isolation leads to… Change in gene frequency in a population
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Divergent Evolution Related Present species evolved from common ancestor
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Convergent Evolution Not closely related Dissimilar features evolved to become similar features
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Parallel Evolution Related & Isolated Corresponding features undergo equivalent changes in isolated environments
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Organic Evolution Present day species are descendants of previous species Changes that have taken place in plants & animals over time
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Vestigial Structures Phylogenetic remnant Better developed in ancestor E.g. pelvic girdle in python
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Key Point Can you think of a vestigial structure in humans?
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Rudimentary Structure More developed in descendant E.g. neck, ear
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Ontogeny An individual’s life history Fertilization to death Influenced by environment as well as genetics Structures earliest to develop are likely the oldest phylogenetically
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Heterochrony Paedogenesis – Gonads develop quicikly Paedomorphosis – Immature features of ancestor become features of future SPECIES Neoteny – Immature features are retained as an adult in the INDIVIDUAL
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paedomorphosis
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