The Evolution of Evolutionary Thought: Part 3, Fossils

In a previous post, you learned that evolution is a theory, and a theory is something that all the scientific evidence supports. In another post, you learned about the theory of evolution. But, how did the theory of evolution come about? What was the evolution of evolutionary thought?

Well, in order for the theory of evolution to be developed, some ideas needed to change. In a previous post, we looked at ideas about the relationship between humans and other forms of life. In the last post, we looked at ideas about the age of the Earth. We will continue our study of evolutionary thought by exploring fossils and what they implied about life. People’s ideas about when life was created needed to be changed in order for the theory of evolution to be developed.

The OLD IDEA was: All organisms were created at the same time, exactly like they are now.

The NEW IDEA was: Different organisms lived in different times, and organisms change over time.

In the last post, we learned that geology showed the Earth to be older than 6,000 years, which seemed to contradict the Bible. Well, another piece of geology was also causing problems. Fossils. For hundreds of years, people were finding fossils but didn’t know what to make of them. For example, some thought maybe they were deformed organisms or some kind of trick of nature. Then, in the 1600s, Robert Hooke examined fossils under the microscope and realized that fossils were organisms that had lived before.

So, people then realized that fossils were the remains of previous organisms, but they also saw that many of these fossils were of animals that no longer existed. For example, there were fossilized dinosaurs, elephants and saber-toothed tigers in Europe, and these organisms were no longer found there. This was a problem. If all life was created by God at the same time, then why weren’t some organisms still around?

To explain these fossils people looked to the Bible again, and decided that fossilized animals were killed in the Great Flood in the Bible’s book of Genesis, because these organisms did not make it onto Noah’s Ark.

Then, in 1813, Georges Cuvier came up with the idea of extinction to explain these fossils of animals who no longer existed. He used the idea of catastrophism (which I mentioned in the last post) to explain what caused the extinctions. He said that the earth had experienced a series of catastrophes, one of them being Noah’s flood, and that made lots of animals extinct.

But, the fossil record showed that different organisms lived in different times, and this meant that the world used to be very different than it was then. The fossils also showed that organisms became more complex over time. But if all life was created by God at the same time and all life was now just like it was at creation, this didn’t make sense. Eventually, scientists started thinking that organisms might be changing over time.

Erasmus Darwin, Charles Darwin’s grandfather, created one of the first theories of evolution. He said that all life came from an original filament (God) and that the slow change of one species to another species resulted in all the various forms of life on Earth. His grandson used some of his ideas over 50 years later in the famous theory of natural selection!

In summary, people thought that all organisms were created at the same time, and stayed exactly the same as they are now. But fossils showed that some animals don’t exist anymore, and so Georges Cuvier came up with the idea of extinction to explain this, along with the idea of catastrophism. Eventually, scientists thought maybe organisms were changing over time, and Erasmus Darwin suggested one of the first theories of evolution. In the next blog post, we’ll explore ideas about adaptation to the environment.

Want to learn more about evolution?

Just take my Udemy course, “Exploring Genetics and Evolution Through Physical Anthropology: Anthropology 4U” at this link.

Thanks for reading!