Why Scientists Believe in Evolution

Evolution is the change in genetic traits of populations that occurs over successive generations. We have evidence that populations have changed over time. The most commonly known evidence comes from the fossil record. This record shows that over time, populations have had modifications that led to their physical structure today.

Other evidence comes from the current distribution of species around Earth. One such piece of evidence is the differences between species on islands compared to their relatives on the mainland. Evidence such as this is further supported by our understanding of genetics. For example, we know that every organism shares the same basic genetic code. The pattern of this code between species matches the relatedness we had concluded from the other kinds of evidence. Comparing the genome of species is also considered a repeatable experiment: a scientist in any lab around the world can get the same results in comparing the DNA of different specimens of the same species.

Because of this, most scientists see evolution as a fact (i.e., it is an observation that has been confirmed many times, and in many different situations, that scientist see it as certain). When scientists refer to “the theory of evolution” they are referring to the models we use to explain how life evolves on Earth.

Scientists have suggested different ideas about how evolution works. Many people use powerful metaphors to explain these ideas.

Do these examples sound familiar?

• Evolution is “survival of the fittest.”
• “Genes want to make more copies of themselves.”

These metaphors don’t accurately explain what scientists believe about evolution today. But metaphors are easy to remember, so they stick with people. These metaphors can easily become misconceptions. And they’re hard to get rid of!

This video explains the origins of some common misconceptions about evolution. It also explains why these explanations are not correct.

We cannot observe evolution directly. However, scientists have accumulated a lot of evidence to show that organisms evolve. The theory that explains how evolution occurs is one of the most solid theories in all of science!