1. Continental Drift

2. Continental Drift Theory Proposed by Alfred Wegener in 1912 250 million years ago, all of the continents were combined into one super-continent called “Pangaea” The continents gradually drifted apart to where they are today

3. Continental Drift Alfred Wegener’s hypothesis - The hypothesis that Pangaea broke apart into continents.

4. Evidence to Support the Theory

5. “Puzzle Pieces” Continents look like they could be part of a giant jigsaw puzzle

6. Distribution of Fossils Plant and animal fossils found on the coastlines of different continents Mesosaurus (reptile that lives on land and fresh water) found in South America and Africa Glossopteris (plant) found on Africa, Australia, Asia, South America and Antarctica

7. Glaciers and Rocks Traces of glaciers found in many tropical regions of Earth When continents drifted apart, glaciers melted away Glaciers leave tracks, scouring and polishing rock surfaces

8. Rocks Similar rock structures found on different continents: - Rocks found in Appalachian Mountains similar to rocks in Greenland and western Europe - Rock structures from eastern South America similar to western Africa

9. Climates Fossils of warm-weather plants found on Spitsbergen (an island in the Arctic Ocean) Spitsbergen Island might have drifted to the Arctic from a tropical region of Earth

10. Problems With The Theory Theory was not accepted by scientists because there was not enough evidence (NO PROOF!) Wegener could not explain what caused the continents to break apart and drift away He hypothesized that continents plow through the ocean floor or that the spinning of Earth on its axis was the cause

11. Homework (ISN) * Write a 1 paragraph summary and draw a diagram about continental drift theory.