Question

How does the fossil record support the theory of continental drift?

Answer 1

The theory of continental drift explains- how the continents that were earlier joined- drifted apart from each other over time through their movement.

Complete answer:
Wegener, in the early 20th century, proposed the theory of continental drift, which stated that all the continents were earlier joined together to form a supercontinent called- Pangea. The continents broke down into pieces and drifted apart to their current positions. The movement of these continents took place by the expansion of ocean floors. This happened due to the development of cracks in the ocean bed or floor.
Alfred Wegener was a geologist who observed the coasts of Western Africa and Eastern South America. He visualized these two coasts like two puzzle pieces that can fit into each other. He supported this theory by showing the evidence of fossil records which explains how the continents must have been joined together. Various fossils of animals and plants are found in the rock from similar ages in different lands, hence justifying the theory. Some of these fossil records are-

1)Fossils of a freshwater crocodile-like reptile called Mesosaurus- have been found in the lands of Brazil and Western Africa in the rocks of the same age. They lived during the early Permian period.
2)Fossils of a land reptile called Lystrosaurus- are found in the lands of Africa, India, and Antarctica in the rocks of a similar time. They were dominant during the Triassic period and were herbivorous.
3)Fossils of an extinct mammal-like reptile called Cynognathus- were found in the lands of South America and South Africa in the rocks of similar age. They lived during the mid-Triassic period.
4)Fossils of a woody seed-bearing shrub/tree - Glossopteris, were found in the lands of Australia, South Africa, South America, India, and Antarctica in the rocks of similar age. They lived dominantly during the Permian period.
5)Fossils of Tropical plants are found in the Arctic region. They support this theory as they otherwise- could have not grown in the enormously cold climate of that region.
6)Fossils of glacial deposits are found in areas that do not have glaciers at present, like South Africa.
7)These records are supported as it would have been practically impossible for the plants and animals to swim the large distances of the ocean to reach the other continents.

Note: The other factors that support the theory of continental drift are- geologic fit of the continents, ancient distribution of rocks and mountains, and the location of ancient climatic zones across the planet.
Alfred Wegener’s theory was rejected as he was incapable to explain the movement of these continents.