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Published byTerence Jack Waters Modified over 8 years ago
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Evidence of Evolution
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1) Fossil Record 2) Geographical Distribution 3) Homologous Body Structures 4) Similarities in Embryology
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Fossil Record Shows how different groups of organisms have changed over time
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Type of Rock Fossils are Most Commonly Found In Sedimentary Rock
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How Fossils are Formed 1) Dead organisms sink to the bottom of bodies of lakes and seas 2) Streams and rivers carry small rock sediments (sand, silt, clay) to lakes and seas 3) Rock sediments bury the dead organism 4) Multiple layers of rock sediments turn into sedimentary rock and preserves the dead organisms
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How Fossils Form
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Using the picture below where would the OLDEST fossils be found? ABAB C D E F
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2 Ways to Determine the Age of Fossils 1) Relative Dating 2) Radioactive Dating
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Relative Dating Definition: ESTIMATING a fossil's age by comparing its placement with that of fossils in other layers of rock
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Relative Dating using Index Fossils Index Fossils Fossils that are commonly found in certain layers of rock
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Explaining Relative Dating with Index Fossils
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Radioactive Dating Definition: Calculating the ABSOLUTE age of a fossil based on the amount of radioactive isotopes it contains
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Radioactive Dating and Half Life Half Life Amount of time needed for half of the radioactive isotopes in a sample to decay
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Radioactive Isotopes Scientists Look for in Fossils 1) Carbon 14 (found in the youngest fossils) 2) Potassium 40 3) Uranium 238 (found in the oldest fossils)
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Practicing Calculating Half Life I have 200 grams of Cool Rock. Cool Rock has a half life of 2 years. How many years does it take for cool rock to turn into 12.5 grams?
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Practicing Calculating Half Life I have 400 grams of Pluton. Pluton has a half life of 4 years. How many years does it take for Pluton to turn into 50 grams?
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Is the following statement referring to Relative Dating or Radioactive Dating? A scientist is comparing two rocks. One is 3.5 billion years old the other 25,000 years old.
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Geographical Distribution 1) Adaptive Radiation 2) Convergent Evolution
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Adaptive Radiation Species all deriving from a common ancestor have over time adapted to their environment The finches' common ancestor is found in South America. Each species of finches is found on different Galapagos Islands.
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Convergent Evolution When unrelated organisms resemble each other because they live in similar environments
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Homologous Body Structures Structures that have different mature forms but develop from the same embryonic tissues
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Homologous Body Structures The limbs of each of these organisms have the same basic bones which supports the theory that at some point they shared a common ancestor
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Vestigial Organs Traces of homologous structures Rabbit Human
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Similarities in Embryology The early stages of embryos with backbones are very similar
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