BIO 3220

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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
• Darwins 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 individuals 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