Fossil Distribution

If the continents were really once joined together at one time, with matching geological features, Alfred Wegener believed that there would be matching plants and animals on either sides of matching continents. To check this hypothesis, Alfred Wegener turned to the fossil record. It revealed that identical fossilized plant and animal species have been found in many different places, on different continents. It suggested that they evolved together as the continents were together and after the split, evolved separately.

To help support the understanding of fossil distribution, biologists contribute by giving further evidence explaining how some animals come from a common ancestor but evolved into various types resulting from differences in their environment, which ties in with the theory of evolution.

Many of the species that lived at the time are now extinct and so fossils provide the only record to show how they were distributed. The picture below shows that when the continents are fitted together, the distribution of fossils form a continuous pattern just like the matching of geological formations.

By looking at the map, it seems impossible for such similar organisms to exist so far away from each other, unless these life forms once lived all together on a single continent. Wegener stated that these organisms could not have crossed the vast oceans by simply swimming or being carried by wind or water.

An example is the ancient fern Glossopteris. Many believed the seeds of this plant had been carried by wind or water across the continents. However, the seeds of Glossopteris were large and heavy and therefore it was unlikely they could be carried far, let alone whole landmasses.

Some geologists had suggested that land bridges once linked continents, enabling animals to travel back and forth between the separated continents. The idea of land bridges to me, would be a logical reason to explain why similar fossils are being found on different landmasses. Most scientists believed that after the lowering of sea level during an ice age, it allowed animals to cross the narrow Bering Strait between Asia and North America. To prove land bridges still exist, pieces of its remains should still lie below sea level. However, no signs of any land bridges have ever been found in the Atlantic Ocean.

The video helps illustrate  the change in sea level from the peak of the last ice age to the present.

The evidence of fossil distribution and cross-geological formations were major discoveries that contributed to my understanding of continental shapes and how the continents were once joined together.