UCSB Science Line
Sponge Spicules Nerve Cells Galaxy Abalone Shell Nickel Succinate X-ray Lens Lupine
UCSB Science Line
How it Works
Ask a Question
Search Topics
Our Scientists
Science Links
Contact Information
How did fossils provide evidence for continental drift?
Answer 1:

Fossils are the buried pieces of animals from a long time ago. We know that some animals only live in certain areas -- for instance, if you found a fossil of a fish, you would know that at the time when the fish was alive that part of the world was an aquatic environment. How about if we found tropical fish -- we would know that it was a warm ocean when those fish were living. There are many places on earth where we could find tropical fish, but how about if we found a fossil kangaroo? We know that kangaroos are only found on Australia. Let`s pretend that you found a kangaroo fossil on the southern tip of India, you would then think that India must have at one point been attached to Australia, otherwise how would the kangaroos have gotten there when Indian is so far away from Australia?

We have found fossils of animals and plants that existed in a small area of the world, but they exist on what is today 2 continents -- but we know they only existed in one place, so we can deduce that those continents were once attached together, and have now separated!

We can use fossils to re-construct how our continents were, to re-trace continental drift and calculate how they were spread out on the earth millions of years ago.

Answer 2:

Fossils show that the continents drifted because similar fossils were found where the continents were together millions of years ago. For example, Africa and South America fit together like this:

click here please

There have been fossils found of a crocodile that lived in that region on both Africa and South America, suggesting that when the continents were together, the animal lived there. When they died, the continents split apart leaving identical dead crocodiles thousands of miles apart:


Answer 3:

Different kinds of animals and plants live in different parts of the world. This is true now, and it was true in the past. As a result, if you find fossils of the same animal or plant on different continents now, then that is evidence that those two continents may have been a single continent when those fossils were formed.

Answer 4:

Before geologists accepted the continental drift theory, paleontologists knew that certain fossils of ancient land creatures could be found on continents that are separated by thousands of miles of ocean. For example, fossils of ancient reptiles called Cynognathus and Mesosaurus have been found on South America and Africa. Also, fossils of the plant Glossopteris have been found on South America, Africa, India, Antarctica, and Australia.

The only way these fossils can be found on continents that are separated by oceans is if the continents were once together (connected). These ancient animals and plants could not have swam across oceans! Therefore, these creatures must have lived on a giant continent that later broke apart, and the pieces drifted away from each other. Fossil records are strong evidence that the continents do drift.

Answer 5:

Fossils are formed when living organisms (plants or animals) die and become buried in dirt, sand or mud. Over time, the organism decays and the area it occupied is replaced with inorganic rock. Fossils from certain organisms have been found in similar rock formations but on different parts of the planet. Fossils made by the same type of organism in the same type of rock were likely formed at the same time and in the same place. The rock that contained the fossils must have moved after they were formed. (That the organism lived separately on both sides of the planet and happened to die in similar terrain is much less likely.) By looking at where fossils from different organisms are now and the age of the rock they are in, scientists can build a picture of the path that the rock must have taken to get there. For example, dinosaur fossils found in South America and Africa provide evidence that the two continents used to be part of the same larger land mass, Gondwanaland: click here please

The theory of continental drift (famously argued by Alfred Wegener in 1921) did not become widely accepted until we could explain why and how the continents moved. The theory of plate tectonics (proposed by Samuel Warren Carey in 1958) proposed that the surface of the Earth is composed of large plates that float on liquid rock (magma). The plates are formed when the liquid rock is exposed to the surface and destroyed when they are pushed back into magma layer. The formation and destruction of the plates provides the driving force for the continents to move over time.

Click Here to return to the search form.

University of California, Santa Barbara Materials Research Laboratory National Science Foundation
This program is co-sponsored by the National Science Foundation and UCSB School-University Partnerships
Copyright © 2015 The Regents of the University of California,
All Rights Reserved.
UCSB Terms of Use