Homologous and Analogous Structures

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

8. 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

9. Vestigial Structures

10. 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

11. Vertebrate Embryos

12. 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!!

13. 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!

15. 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

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

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