Continental Drift Theory Presented by Kesler Science Essential

Continental Drift Theory Presented by Kesler Science

Essential Questions: 1. 2. 3. Who is Alfred Wegener What is the historical evidence that supports the Continental Drift Theory? What causes the movement of the continents?

Continental Drift Theory Meet Alfred Wegener (1880 – 1930) • Proposed the Continental Drift Theory - The idea that Earth’s continents moved apart from a single large continent called Pangaea • Despite a large body of compelling fossil and rock evidence, his theory was rejected by most other scientists. • He could not explain “how” the continents moved. • It was only in the 1960 s that the Continental Drift Theory finally became accepted and became part of the Theory of Plate Tectonics. © Kesler. Science.

Continental Drift Theory Pangaea • Was a super continent • Began to break apart about 175 million years ago • There were probably other supercontinents before Pangaea. • The Earth’s continents have been continually breaking apart and coming together. © Kesler. Science.

Continental Drift Theory Laurasia and Gondwanaland • Gondwanaland separated from Laurasia between 200 -180 million years ago. • This roughly formed the northern and southern hemispheres. © Kesler. Science.

Continental Drift Theory Wegner’s Supporting Evidence • Fossil evidence • Continental Fit • Glacial evidence • Landforms & Rock Layers © Kesler. Science.

Continental Drift Theory Fossil Evidence • Fossils of the same species were found on separate continents and nowhere else. • These plants and animals would have had to evolve independently or swim the distances. • Fossils found didn’t fit the climate. (Palm tree leaf fossils were found in Alaska. ) © Kesler. Science.

Continental Drift Theory Continental Fit • The continents, particularly South America and Africa, fit together like puzzle pieces. • This was another piece of evidence that the continents were once joined. © Kesler. Science.

Continental Drift Theory Glacial Evidence • Glacial deposits formed 300 mya are found in Antarctica, Africa, South America, India and Australia. • Striations (scratches on rocks) show the ice flowing from the glaciers came from a single point. • Evidence of glaciers is found in warm climates today. © Kesler. Science.

Continental Drift Theory Landforms and Rock Layers • The Appalachian Mountain matched well with those on the British Isles as well as other places. • Similar types of rocks and similar ages of rocks were found on these three continents and other places. • The coal fields in North America and Europe match up. © Kesler. Science.

Quick Action – Continental Drift Theory The Great Debate As a scientist how would you feel if years of your research was discounted, unnoticed, or completely rejected? That has happened to many of our great scientists over the decades. Years after their death many of those theories became accepted. Write an argument for the Theory of Continental Drift and an argument against the Theory of Continental Drift. © Kesler. Science.

Check for Understanding Can you… 1. Identify Alfred Wegener and his contributions to the Continental Drift Theory? 2. Explain the historical evidence that supports the Continental Drift Theory? 3. Describe the process that moves the continents. © Kesler. Science.