how did Wegener use plant and animal fossils to prove continental drift

Question

The plants and animals crossed the oceans to get to the other continents
oceans did not exist for those plants and animals to cross
the continents must have connected at one time and they have moved since then
The plants and animals were taken to new continents by humans

Answer 1

Alfred Wegener used plant and animal fossils as key evidence for his theory of continental drift by highlighting that similar fossils were found on continents that are now widely separated by oceans. His reasoning was based on several points:

1. Fossil Distribution: Wegener noted that certain species of plants and animals, such as the freshwater reptile Mesosaurus and the Glossopteris plant, were found on continents like South America, Africa, Antarctica, and Australia, which are currently separated by vast oceans.

2. Impermeable Oceans: He argued that these species could not have crossed the oceans that separate the continents today due to their inability to swim or travel long distances in the open sea. Therefore, the only logical explanation for their presence on multiple continents was that those continents were once joined together, allowing these organisms to inhabit a continuous land area.

3. Connected Continents: By demonstrating that the distribution of these fossils matched on continents that had once been connected—such as in the supercontinent Pangaea—Wegener supported the idea that the continents have drifted apart over geological time.

So, the correct conclusion from Wegener’s observations is that the continents must have connected at one time and they have moved since then. This was a pivotal piece of evidence in forming his hypothesis of continental drift.