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Evidence For Biological Change Across Time

Evidence For Biological Change Across Time. Paleogeologists use Fossils in Strata. The more deeply buried the fossil, the more time has gone by, and the older it is. Layers of rock with fossils show us their relative age: which is older and which is more recent.

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Evidence For Biological Change Across Time

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  1. Evidence For Biological Change Across Time

  2. Paleogeologists use Fossils in Strata • The more deeply buried the fossil, the more time has gone by, and the older it is. • Layers of rock with fossils show us their relative age: which is older and which is more recent.

  3. Fossils in Strata Inferences • By looking at a sequence of related fossils and their relative ages, relationships and changes through time can be inferred. • Radiometric dating provides more accurate ages.

  4. As gaps in the fossil record are gradually filled, we see transitions

  5. Evolutionary Biologists study Homologous Structures • Similar body parts are modified and used differently in different life forms. • Homologies give clues to common ancestry. • They must have shared a common ancestor who had similar structures

  6. And Vestigial Structures • If a body part changes in a way that it becomes no longer used or useful, it is called vestigial, or a “vestige” of the former structure.

  7. Developmental Biologists compare embryo development Which one is the Cat? A = Cat B = Cow C = Horse D = Human

  8. Changes accumulate in DNA over time

  9. By comparing DNA, we can see how closely related life forms are

  10. Known rates of mutations allow us to use DNA as a “molecular clock”We can use it to make more accurate inferences about common ancestors

  11. Physical Anthropologists study changes in hominid anatomy Observed Changes?

  12. (A) Pan troglodytes, chimpanzee, modern (B) Australopithecus africanus, STS 5, 2.6 My (C) Australopithecus africanus, STS 71, 2.5 My (D) Homo habilis, KNM-ER 1813, 1.9 My (E) Homo habilis, OH24, 1.8 My (F) Homo rudolfensis, KNM-ER 1470, 1.8 My (G) Homo erectus, Dmanisi cranium D2700, 1.75 My (H) Homo ergaster (early H. erectus), KNM-ER 3733, 1.75 My (I) Homo heidelbergensis, "Rhodesia man," 300,000 - 125,000 y (J) Homo sapiens neanderthalensis, La Ferrassie 70,000 y (K) Homo sapiens neanderthalensis, La Chappelle-aux-Saints, 60,000 y (L) Homo sapiens neanderthalensis, Le Moustier, 45,000 y (M) Homo sapiens sapiens, Cro-Magnon I, 30,000 y (N) Homo sapiens sapiens, modern

  13. Discovering Ardi: After school “Movie Night” 2:30-4:30, Wednesday: Up to 10 points extra credit

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