IntroductionEvolution is perhaps the most important concept in biology. As discussed before, it is one of the unifying principles of biology. Indeed, most scientists would list it as the unifying topic. It has often been said that nothing in biology makes sense without evolution.
The theory of evolution is not disputed among scientists. Observations and evidence collected and examined over the past 150 years supports this theory as much as, or even more than, other theories such as the atomic theory, the cell theory or the theory of gravity. However, the exact mechanisms of evolution, the details of how it occurred and continues to occur, are, in deed, disputed. This is the challenge and excitement facing researchers today.
Evolution is refuted by some nonscientists, mostly fundamentalist, who believe in creationism, the idea that all living things arose through divine creation in their present forms. A few points are important to understand in this debate:
- Science cannot prove or disprove the existence of God. Faith is not in the realm of science. We can, however, gather evidence to support or refute scientific questions, such as whether or not evolution occurred. In this case, we can no longer ignore or disregard this process. It is, in scientific terms, a fact.
- Many religions, including the Catholic and Protestant churches and all but the most conservative Jewish sects, recognize and do not dispute the major tenants of evolution. Most believe, however, that humans are special in that a divine creator has given us something, a soul or free will, that sets us apart from all other living things.
- Evolutionary theories do not address the origins of the earth or necessarily the beginnings of life. Evolution is defined as, and is used to describe, change with time.
There are many aspects of and ways to study evolution. We will only discuss some of the basics in this chapter.