our earth. what do you think the earth looked like long ago?

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Our Earth

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  • Slide 1
  • Our Earth
  • Slide 2
  • What do you think the earth looked like long ago?
  • Slide 3
  • Do you think the map looked exactly the same?
  • Slide 4
  • Could the continents have been closer together?
  • Slide 5
  • Alfred Wegener A scientist who believed the continents used to be close together. He studied the world map and noticed that the continents could fit together like puzzle pieces.
  • Slide 6
  • Theory of Continental Drift Wegeners belief that the continents move.
  • Slide 7
  • Pangaea 1 supercontinent All the landmasses combined About 250 million years ago
  • Slide 8
  • What was the evidence for Pangaea? Geologic Fossils Glacial
  • Slide 9
  • Geological Similar rocks and mountains found on the coast of Southwest Africa and Eastern South America.
  • Slide 10
  • Fossils are the remains from once living things. The same fossils were found on the coasts of continents that fit together. Fossils
  • Slide 11
  • Glacial Glacial deposits (sediments) are found on continents that could have fit together.
  • Slide 12
  • Critics Many scientists did not believe Wegener because he couldnt explain what force moved continents.
  • Slide 13
  • Between the 1950s-1960s, the Theory of Plate Tectonics was developed. This theory stated that continents are part of moving tectonic plates. Evidence of seafloor spreading helped prove this. Theory of Plate Tectonics
  • Slide 14
  • Tectonic Plates Pieces of earths crust Found on the lithosphere. 2 types: a.)oceanic b.)continental
  • Slide 15
  • Seafloor Spreading The widening of the ocean. New oceanic crust is formed through volcanic activity.
  • Slide 16
  • Pangaea Song