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Darwin’s finches have descended with modifications from a common ancestor. Modifications are due to the diversity of ha

Darwin’s finches have descended with modifications from a common ancestor. Modifications are due to the diversity of habitat found in the islands. . What is the evidence that supports descent with modification from a common ancestor? . Homologous structures Vestigial structures

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Darwin’s finches have descended with modifications from a common ancestor. Modifications are due to the diversity of ha

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  1. Darwin’s finches have descended with modifications from a common ancestor. Modifications are due to the diversity of habitat found in the islands.

  2. What is the evidence that supports descent with modification from a common ancestor? Homologous structures Vestigial structures Animal Embryology Paleontology Molecular biology

  3. Homologous structures Structures that are similar in morphology, but have a different function in different species. The forelimb of a human, cat, whale and bat are homologous structures. The forelimb of the these animals has been modified for a particular task.

  4. Vestigial structures Structures with diminished function or no function. Resemble functional structures found in their ancestors. Hind limbs in whales Arrector pili in humans Vestigial structures shows the relatedness of species and descent from a common ancestor

  5. Animal embryology- can you identify the turtle, fish, salamander, human, rabbit and chicken?

  6. Paleontology Remains or impressions of organisms preserved, either in tar, sap, sedimentary rock or other Fossil show adaptations of extinct species. Fossil record is incomplete. Why? 47-million-year-old, lemur-like creature (primate) Darwinius masillae

  7. Molecular biology Similar proteins and DNA sequences are found in closely related species. The more similar the DNA the more closely related the species.

  8. Human evolution and does evolution really matter? http://www.youtube.com/watch?v=W-WumllRPLI http://www.youtube.com/watch?v=x5NG8SYQSzE

  9. What factors increase genetic variation in a population? 1. Genetic Recombination:  When gametes (sperm & eggs) are produced by meiosis, only half of the parents' genetic material is packed into them.  When they unite to form a zygote the result is not exactly like either parent.  Each sexually produced offspring is unique and has variation combinations not present in any other individual of that species.

  10. 2. Crossing over and independent assortment of chromosomes During meiosis, crossing over creates new combinations of genes on a chromosome. Also during meiosis, chromosomes sort independently into gametes creating a vast number of different chromosome combinations.

  11. 3. Mutations Genetic mistakes in DNA occur often during gamete formation.  If DNA is changed, the resulting proteins change and traits never before seen in a species will appear. Most often mutations are detrimental, but on occasion they can give rise to a new, beneficial trait.

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