The scientist Charles Darwin

The English scientist Charles Darwin was the founder of the modern theory of evolution. During a trip around the world, he collected fossils and observed the many variations among living things on a group of islands. From these and other studies, he came to believe that new species developed from earlier forms. In 1859 Darwin published his theory of evolution in an important book called On the Origin of Species. He later wrote a book about the evolution of humans.

Darwin’s work forever changed the way that people think about biology. At first, some people were bothered by the ideas that Darwin presented. One of those ideas was that humans are descended from apes. Others did not accept the idea of evolution for religious reasons. Certain people who follow Christianity believe in the account in the Bible of how the world was created. These people believe that God created each species in more or less its present form. Scientists, however, quickly accepted the idea that plants and animals change over time.

Scientists continue to learn about how evolution works. Darwin was able to show that species develop from each other, but he did not know how that happened. In the early 1900s scientists used ideas from the new science of genetics to explain in detail how traits are passed from one generation to the next. Later advances have allowed scientists to study DNA. These studies help scientists determine how closely related various species of living things are to one another.

Today, some people still do not accept evolution because of their religious beliefs. Instead of evolution, they accept ideas called creationism or intelligent design.