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Evidence of Evolution

Evidence of Evolution

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Evidence of Evolution

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  1. Evidence of Evolution Chapter 15 Part II

  2. 1. Fossil Record • Are able to observe links between modern forms and ancestors (ex. transition species) • Relative age- age compared to other fossils by referring to the geologic time scale and records of known fossils • Absolute age- use of radiometric dating to date rocks

  3. 2. Biogeography • Geographical distribution of species • New organisms arise in same geographic area where similar forms already lived • Example) Australia – has native wolves, cats, mice, moles, and anteaters. Most mammals are marsupials (animals evolved in isolation)

  4. Ex) Ancient Irish Elk

  5. Ex) European Elk

  6. 3. Anatomy and Embryology • Homologous structures- anatomical structures that occur in different species that originated in most recent common ancestor • may have different functions but look similar

  7. Common Ancestor: Bat Human

  8. Analogous Structures-a body part similar in function to another organism due to environmental pressuresEx) the wings of a fly, a moth, and a bird developed independently as adaptations to a common function – flying

  9. Analogy vs. Homology

  10. Vestigial structures- a part of an organism with little or no function but which had a function in an ancestral species

  11. Comparative Embryology- Study of structures that appear during embryonic development • Ex)All vertebrate embryos go though a stage in which they have gill pouches on the sides of their throats

  12. 4. Molecular Biology (DNA and Proteins) • Comparison of DNA, RNA, and amino acid sequences • Greater the number of similarities, the more closely the species are related through a common ancestor • Shows the common descent of the most diverse organisms.

  13. Amino Acid Chart

  14. Evidence of Evolution:fossil evidence, homologous structures, embryology, vestigial organs, biochemical • Bones in bird’s wing and human’s arm are similar in structure. • All organisms use ATP to transfer energy. • There are similarities in structure among the early stages of fish, birds and humans. • Humans, unlike rabbits, have no known use for their appendix. • Horses have increased in size and decreased in number of toes since the Eocene.

  15. Patterns of Evolution • 1. Coevolution • 2. Convergent Evolution • 3. Divergent Evolution

  16. 1. Coevolution • When two or more species have evolved adaptations that influence each other (evolutionary “arms race”) • Examples: • Predator-prey • Parasite-host • Plant-animal pollinator (bee and flower) • Humans have developed and used antibiotics to kill bacteria, bacteria have evolved to become antibiotic resistant

  17. 2. Convergent Evolution • Organisms appear to be similar but are not closely related at all • The environment selects similar traits • Result in analagousstructures • Ex) dolphin and shark

  18. 3. Divergent Evolution • Two or more biological characteristics become more and more dissimilar in response to different habitats

  19. Adaptive radiation- a new population in a new environment (island) will undergo evolution until the population fills many parts of the environment Ex) Galapagos finches

  20. Artificial Selection • The intentional breeding (by humans) of certain traits, or combination of traits, over others