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Notes: Evidence of Evolution

Notes: Evidence of Evolution. Read pgs. 234-240. Objective: Explain what evidence scientists use to support the theory of evolution. Does Evolution Happen?. How do scientists know that evolution happens? What evidence do scientists have that life has changed?. Video: Formation of Fossils.

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Notes: Evidence of Evolution

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  1. Notes: Evidence of Evolution Read pgs. 234-240. Objective: Explain what evidence scientists use to support the theory of evolution.

  2. Does Evolution Happen? • How do scientists know that evolution happens? • What evidence do scientists have that life has changed? Video: Formation of Fossils

  3. Evidence of Evolution • Comparative anatomy: fishes, amphibians, reptiles, birds, and mammals all have an internal skeleton with a backbone.

  4. Evidence of Evolution • Similar body structures: the front limbs of humans, cats, whales and bats are similar in structure.

  5. Evidence of Evolution • Similarities in early development: during early development, all vertebrates have a tail and rows of tiny slits in their throats.

  6. Evidence of Evolution • Similarities in DNA: if two species have similar DNA, they probably evolved from the same ancestor. Video: Evidence of Evolution

  7. Similar Instructions Humans Chimpanzees Gorillas Orangutans

  8. Fossils • Fossil: the preserved remains or traces of an organism that lived in the past. • Fossil evidence supports the theory of evolution. Video: Fossils and Evolution

  9. Fossil Formation • Most fossils form when organisms that die become buried in sediments (bits of soil and rock).

  10. Types of Fossils • Molds: a hollow area in sediment in the shape of an organism.

  11. Types of Fossils • Casts: A solid copy of the shape of an organism.

  12. Types of Fossils • Petrified fossils: fossils in which minerals replace all or part of an organism.

  13. Types of Fossils • Trace fossils: provide evidence of the activities of ancient organisms such as footprints.

  14. Types of Fossils • Preserved remains: the remains of once living organisms can be preserved in things like tar, amber, and ice. Video: Types of Fossils

  15. Paleontologist • Paleontologist: scientists who study fossils to learn about life before humans. Video: Fossils on Galapagos

  16. Fossil Record • Fossil Record: A collection of fossils that show how life on Earth has changed over time.

  17. Fossil Record • The deeper the fossils, the older the organism, the closer to the surface the fossil, the newer the organism. Video: Fossils and History

  18. Fossil Record • Fossil evidence shows that our planet and the things that have lived on it have changed a great deal throughout history. • Since life first appeared on Earth, a great number of species have died out and have been replaced by newer species.

  19. Fossil Record • A large number of gaps remain in the fossil record. This is because specific conditions are necessary for fossils to form. Organisms without hard body parts are not usually preserved. If oxygen is present, much of the organism will not fossilize.

  20. Gradualism • Gradualism: The hypothesis that evolution occurs slowly and steadily.

  21. Punctuated Equilibria • Punctuated Equilibria: The hypothesis that says evolution happens in short bursts followed by long periods of no change. • Scientists believe that a combination of these two hypotheses is how all of the species we have today have developed.

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