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Fossil Evidence of Evolution

Fossil Evidence of Evolution. The Fossil Record. The Fossil Record – made up of all the fossils ever discovered on Earth provides evidence that species have changed over time Fossil – the remains or evidence of once-living organisms. Fossil Formation. Mineralization

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Fossil Evidence of Evolution

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  1. Fossil Evidence of Evolution

  2. The Fossil Record • The Fossil Record– made up of all the fossils ever discovered on Earth • provides evidence that species have changed over time • Fossil– the remains or evidence of once-living organisms

  3. Fossil Formation • Mineralization • minerals in water replace the organism’s original material and harden into rock • Carbonization • extreme pressure drives off the organism’s liquids and gases leaving only the carbon outline

  4. Fossil Formation • Molds and Casts • Mold – impression of an organism in hardened mud or sand • Cast – a fossil copy of an organism in a rock created by sediment filling in the mold

  5. Fossil Formation • Trace Fossils • preserved evidence of the organism’s activity, like footprints • Original Material • original tissues of an organism, like insects in amber (tree sap)

  6. Relative-Age vs. Absolute-Age • Relative-Age – scientists determine the relative order in which rock layers were deposited( Most Accurate when the rock layers are undisturbed.) • Absolute-Age (Radioactive Dating)– scientists use the ratio of unstable isotopes to stable isotopes to find the age of rocks; more precise • ex. carbon-14 dating

  7. The Geologic Time Scale • a chart that divides Earth’s history into different time units

  8. Extinctions • Extinction – occurs when last individual organism of a species dies • Mass Extinction • when many species become extinct within a few million years or less • there have been 5 mass extinctions in the Phanerozoic eon • Causes of Extinction • Sudden change – like meteor impact or volcanic eruption • Gradual change – like tectonic plates or sea level changes

  9. Biological Evolution • the change over time in populations of related organisms

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