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Comparative Anatomy. Evidence for evolution. Homology and Analogy. Homology: A similar physiological structure inherited from a common ancestor. Does not necessarily have the same function!
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Comparative Anatomy Evidence for evolution
Homology and Analogy • Homology: A similar physiological structure inherited from a common ancestor. Does not necessarily have the same function! • Analogy: A similar physiological structure due to convergent evolution. Looks similar and has a similar function!
Homologous Structures (Tetrapod: Animal with four limbs)
Homologies are everywhere… Leaves of an oak tree and of a gingko tree. The wings of a dragonfly and the wings of a butterfly.
And are not always obvious… Each is a modification of the basic incisor tooth structure. Over time, evolution adapted each of these animals' incisors to perform different functions. They are homologous structures, inherited from a common ancestor with incisor teeth.
How do analogies evolve… What happens if the long red flowers disappear?
Criteria for homologies… Same basic structure Same relationship to other features Same development
Vestigial Features and Anatomical Oddities • Structures that serve no function in a living organism.
Vestigial Features and Anatomical Oddities Are these vestigial structures?
Vestigial Features and Anatomical Oddities Are these vestigial structures?
Vestigial Features and Anatomical Oddities What about the pilomotor reflex?