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Evidence for Evolution: Fossils, Anatomy, Embryos, Vestigial Organs, Biochemistry

Explore the lines of evidence that support the theory of evolution. Learn about fossils, comparative anatomy, developing embryos, vestigial organs, and comparing biochemistry.

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Evidence for Evolution: Fossils, Anatomy, Embryos, Vestigial Organs, Biochemistry

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  1. Aim: What lines of evidence are there for evolution? DO NOW: Underline the clue and fill in the missing word in these evolution sentences: 1) Organisms best adapted to a changed environment are more likely to ___________, or mate, and pass off their genes to offspring 2) Evolution causes a population to develop new __________, or useful traits, over time. These new traits make the population more fit for its ____________, or surroundings. 3) Present day life forms have ____________ from, or are descended from, earlier life forms. reproduce Characteristics environment evolved

  2. What evidence is there that supports the theory of Evolution? Evolution is a theory based on evidences that lead to speculated inference. There are 5 main evidence that support evolution: The fossil record Comparing anatomy (body structure) Developing Embryos Vestigial Organs Comparing biochemistry (mainly DNA)

  3. The Fossil Record • A fossil is the preserved remains or impression of an organism that has turned into rock. • Not all dead organisms turn into fossils. The conditions need to be just right for fossilization to occur. • By studying fossils and comparing them with other organisms, scientists can piece together how organisms changed over time.

  4. 1.) The fossil record shows that species do not stay the same over time. Ex. Horse evolution- change in size of horse, structure of foot (from many toes to 1 toe) How do fossils support evolution?

  5. 2.) In some cases, the fossil record shows species that have characteristics of two very different kinds of organisms. These organisms are known as transitional species. * Transitional species are important because they show a direct link from one kind of organism to another. How do fossils support evolution?

  6. Don’t Copy This picture shows an Archaeopteryx. • The drawing is based on fossils that have been found. • ****Archaeopteryx is thought to be the common ancestor of all birds!

  7. Don’t Copy Bird orReptile? ***Archaeopteryx had features of a bird (feathers, bird-like feet) AND features of a dinosaur (teeth and jaws instead of a beak, neck attaches to back of head rather than bottom as in birds, long bony tail).

  8. Velociraptor Ostrich

  9. What are 2 similarities and 2 differences between the skeletons?

  10. Comparing Anatomy 2) Similar structures- Many groups of organisms share similar structures (like bones), because they inherited them from a common ancestor.  Ex. The arms of humans, the forelegs of dogs and cats, the wings of birds, and the flippers of whales all have the same types of bones (humerus, radius, and ulna).

  11. Comparing Anatomy (cont) • The basic body plan of most organisms are the same because the body plan works well. • Because the plans work so well, the genes are passed down from generation to generation. • The body plan may be modified due to a build up of mutations that were beneficial to that particular specie of organism. • These mutations help change the shape of the organ thereby changing the function of that organ.

  12. http://www.youtube.com/watch?v=zGqae7vuUWo http://www.youtube.com/watch?v=8nEwte-x-iw&feature=relmfu

  13. Why do these embryos look the same? 3) Developing embryos of many multicellular animals, seem to resemble each other. As embryos develop, genes turn on and off causing some characteristics to be the same and others not. Because all life came from one ancestral organism, all living things have parts of their DNA in common with other organism. ** all of these embryos had a tail and gills but changed as they continued to develop.

  14. Comparing Embryos (cont) • Because of having similar DNA, different organisms have similar genes. • The embryo diagrams provide evidence that all vertebrates experience similar stages during embryological development.

  15. Vestigial Organs • 4) Vestigial Organs are organs that have no useful function to an individual but still exist. • It is believed that these organs are remnants of organs that were once useful to our ancestor’s survival. • Examples are the human appendix, wisdom teeth, coccyx bone, male nipples, the muscles used to wiggle the ears and the third eye lid.

  16. 4) Comparing Biochemistry(molecular evidence) 4 A.) Looking and comparing DNA from different organisms is the most accurate way to trace ancestry. a) All organisms have DNA. b) The genetic code (codon to amino acid chart) is the same for all organisms. All organisms use the same code for the same amino acids. c) Using electrophoresis, if there are similar band patterns, that means that those organisms have the same genes. The more genes they have in common the more related they are.

  17. Hemoglobin Amino Acid Sequence

  18. Amino acid Amino acid Amino acid Amino acid Amino acid PROTEIN B. Protein similarities If two organisms have the same proteins, that means they have the same genes. The more genes they have in common the more related they are. Example: Human hemoglobin and gorilla hemoglobin are the same protein, therefore both organism have the same gene for hemoglobin.

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