The observation that the continents fit together like puzzle pieces, and may once have been connected, led Alfred Wegener to propose a theory in 1910 called A: continental plowing B: continental drift C: wandering continents D: seafloor spreading 2. The essence of Wegener's idea was sound, based on some scientific observations. Which of the following supported his theory? A: Matching fossil plant remains found on two different continents B: Matching reptile remains found on two different continents C: nearly identical sedimentary rock types of same age in widely separated locations D: all of the above 3. The development of submarine warfare during World War II created a pressing need to map the ocean floor. This actually led to research on the ocean floor that would help explain the movement of the continents. What tool was used to do this mapping? A: underwater cameras B: sonar surveys C: studies of living things D: rock sampling 4. Scientists found that the continents were moving apart from each other due to magma rising out of mid-ocean ridges, and they called this A: sea floor spreading B: sea floor rising C: changing sea floor D: underwater volcanoes 5. The Earth's continents were once connected in one giant continent called A: Eurasia B: Indo-Australia C: Pangaea D: Gondwanaland

Continental Drift

Theory proposed by Alfred Wegener in 1912 His idea was that 250 million years ago there was a supercontinent he called PANGAEA

Pangaea splits to form: Gondwanaland= South America, Africa, Australia, Antarctica, Madagascar, & India Laurasia= Europe, Asia, & North America

Geologists told Wegener to… “PROVE IT!” …and he said “ok”.

Evidence to Support Continental Drift

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

2. Distribution of Fossils Plant & animal fossils found on the coastlines of different continents

Example: Fossil clues (Mesosaurus) -it couldn’t swim across oceans so how did it get from South America to Africa?

3. Mountain Ranges Rocks that make up the Appalachian Mountains can be found in eastern North America, Greenland, and some of Europe *we know they are the same mountains because they are the same age and are made of the same minerals and fossils

4. Ancient Climates Glaciation in Africa, South America, India, and Australia during the same time

So, with all that evidence, how do other scientists react to Wegener’s theory of Continental Drift?

Other scientists REJECT Wegener’s hypothesis! WHY? He hasn’t explained HOW the continents are moving!

But, Wegener’s idea must not have been too bad of an idea because we are studying it today…so what changed? Another scientist named Harry Hess came up with a theory of how the continents moved. This happened in 1968.