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Evidence for evolution

Explore the geologic timeline through fossils and evidence of continental drift, plate tectonics, and genetic changes. Discover the different ways fossils are formed and learn about the methods used to date them.

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Evidence for evolution

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  1. Geologic Structural Genetic Evidence for evolution

  2. Geologic evidence: • Geologic timeline from fossils • Continental Drift • Plate tectonics

  3. Continental Drift

  4. Evidence for evolution: Fossils Observation: Fossils have been found and dated. Inference: Comparing fossils to living species today indicates living organisms have changed over time. Trilobite (extinct marine invertebrate) found in Ohio—site of an ancient sea

  5. Fossils can form in several ways. 1. Permineralization The minerals form a covering over the bones. Permineralized skeleton of a Velociraptor dinosaur

  6. Natural cast • Minerals fill in the spaces left from decomposition, recreating the original shape. Cast of a crinoid, a marine animal

  7. Leaf imprints • Footprints 3. Trace fossils. Fossils of footprints from a Dimetrodon dinosaur

  8. Amber-preserved fossils • organisms are trapped in tree resin Wasp

  9. Preserved remains • an entire organism becomes encased in ice, volcanic ash, or mud. Ice preserved 5000 year old man found in the Italian Alps.

  10. Only a tiny percentage of living things became fossils • Nevada’s state fossil: the icthyosaur which is the ancestor of the dolphin • We have the Icythyosaur State Park in central Nevada as Nevada was once underwater • Specific conditions are needed for fossilization.

  11. Fossils: Links to the past… Scientists have an incomplete picture of past life on Earth because: • Not all bones become fossils. - Conditions - Predated by animals • We have not found all fossils

  12. Dating the age of Fossils • Law of superposition • Estimates the age of fossil • It compares the placementof fossils in layers of rock. Radioactive isotope dating (Uranium used for really old aging Carbon 14 dating most common)

  13. Law of Superposition

  14. Radioactive dating

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