5.7: Plate Tectonics- Challenge 1

1. Historically, ___ covered most of the earth, but today they form only on land and near the poles.

glaciers

2. ___ of prehistoric organisms have been found on widely separated continents, suggesting that these organisms once lived in the same regions or could travel between them easily.

Fossils

3. The Theory of Continental Drift states that ___.

the earth's crust consists of several different continental plates that are constantly moving.

4. Scientists rejected Wegener's theory, because ___.

no plausible mechanism to explain continental movement was known

5. Alfred Wegener died in ___ on an expedition to ___.

1930; the Greenland icecap

6. Magnetic crystals in older rocks of the same age on the same continent point to ___.

the same point, but not the current magnetic pole

7. What line of evidence made scientists realize that Wegener was right about continental drift?

Apparent polar wander

8. ___ crystallizes from fluid lava and points to the north magnetic pole as the lava cools.

Magnetite

9. Flat-topped mountains in the ocean are known as ___.

guyots

10. Who proposed the theory of seafloor spreading in the early 1960s?

Harry Hess