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The Evolution of Evolutionary Thought: Part 2, Age of the Earth

Image of the Earth from space

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 the last post, we looked at ideas about the relationship between humans and other forms of life. In this post, we will continue our study of evolutionary thought by exploring the age of the Earth. People’s ideas about the age of the Earth needed to change in order for the theory of evolution to be developed.

The OLD IDEA was: The Earth is very young. 

The NEW IDEA was: The Earth is very old.

Age of the Earth. Image of a black Bible with gold lettering.

Before science became a thing, people in Europe got all their answers from the Christian Bible. So, they thought that the Earth was created in 6 days, and it must not be very old. James Ussher analyzed the Bible and determined that creation took place in 4004 B.C, and so he said the Earth must be only about 6,000 years old. 

John Lightfoot said creation happened on exactly October 23rd at 9am. You might be wondering how he got this exact time and date. Well, what’s interesting is that Lightfoot was the vice-chancellor of Cambridge University, and that was the same day and time his school started the fall term. 

But then scientists started seeing evidence that the Earth must be a lot older—for example, geology showed an awful lot of changes for only a 6,000-year-old Earth. So, to explain this, some started to think maybe there were lots of catastrophic events, like earthquakes and volcanoes, which changed the Earth into what it was today. This was called catastrophism

Age of the Earth. Image of a volcano surrounded by water with steam coming from the top.

But the more geology was studied, the more obvious it was that the Earth had to be older than 6,000 years old. James Hutton came up with the idea that all the geological processes we can see now, like erosion, worked the same way in the past. And, since these processes took a lot of time, the Earth must be older than everyone thought. This was called uniformitarianism

Then in 1830, Charles Lyell took this idea and created the concept of deep time, which meant that the Earth was way older than 6,000 years. He said that rainfall, soil deposition, and other geological processes slowly made and altered the Earth’s surface, a process that had to have taken much longer than 6,000 years—probably over a period of millions of years. 

In summary, Europeans thought that the Earth was only 6,000 years old, based on the Bible. But geological evidence showed that the Earth was much much older. James Hutton and Charles Lyell suggested the concept of uniformitarianism, which said that geological processes slowly altered the Earth’s surface, and this slow process had to have taken millions of years. People now began to realize that the Earth was very old. In the next blog post, we’ll explore yet another idea that had to change in order for the theory of evolution to be developed.

Want to learn more about evolution?

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

Thanks for reading!

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