The theory of evolution is just that -- a theory. According to "The American Heritage Dictionary," a theory is:
A set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena.
Evolution is a set of principles that tries to explain how life, in all its various forms, appeared on Earth. The theory of evolution succeeds in explaining why we see bacteria and mosquitoes becoming resistant to antibiotics and insecticides. It also successfully predicted, for example, that X-ray exposure would lead to thousands of mutations in fruit flies.
Many theories are works in progress, and evolution is one of them. There are several big questions that the theory of evolution cannot answer right now. This is not unusual. Newtonian physics worked really well for hundreds of years, and it still works well today for many types of problems. However, it does not explain lots of things that were eventually answered by Einstein and his theories of relativity. People create new theories and modify existing ones to explain the unexplained.
In answering the open questions that still remain unsolved, the theory of evolution will either become complete or it will be replaced by a new theory that better explains the phenomena we see in nature. That is how the scientific process works.
Here are three common questions that are asked about the current theory of evolution:
- How does evolution add information to a genome to create progressively more complicated organisms?
- How is evolution able to bring about drastic changes so quickly?
- How could the first living cell arise spontaneously to get evolution started?
Let's look at each of these questions briefly in the following sections.