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Homologous and Analogous Structures

Homologous and Analogous Structures. Homologous structures. Structures that are similar but has different functions Shows common ancestry. Convergent Evolution. Acquiring the same biological trait independently Example: Flight

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Homologous and Analogous Structures

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  1. Homologous and Analogous Structures

  2. Homologous structures • Structures that are similar but has different functions • Shows common ancestry

  3. Convergent Evolution • Acquiring the same biological trait independently • Example: Flight • Humming bird and moth - last common ancestor did not have wings • They acquired these traits separately • Only very few designs for a wing would allow for hovering

  4. Porpoises

  5. Sharks

  6. Analogous Structures • Similar functions but differ in structure • Ex: wings of a hummingbird and humming moth – both can hover to feed

  7. Vestigial Structures • Features that were useful to an ancestor, but they are not useful to the modern organism that has th. • tailbone in humans • Appendix • Some snakes have tiny pelvic bones and limb bones

  8. Vestigial Structures

  9. Comparative Embryology • Closely related organisms often have similar stages in their embryonic development • All vertebrate embryos are similar • Vertebrates share a common ancestor lemur pig human

  10. Vertebrate Embryos

  11. Similarities in Macromolecules: • The more similar homologous proteins are in different species, the more closely related the species are thought to be. • Ex: the amino acid sequence in human hemoglobin and gorilla hemoglobin differ by ONE amino acid • While the Hbof humans and frogs differ by 67 amino acids!!

  12. Coevolution • Change of two or more species in close association with each other • Predators and their prey sometimes co-evolve • Pollinators • Bees can’t see red, but can see in blue, yellow, and UV • Bee landing pad!

  13. Divergent Evolution • Two or more related populations or species become more and more dissimilar. • Divergence is nearly always a response to differing habitats and can result in new species

  14. Adaption Radiation • Many related species evolve from a single ancestral species ex: Galapagos finches

  15. Canisfamiliaris artificial selection: all domestic dogs are the same species “Canisfamiliaris”

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