One exciting thing about the theory of evolution is that we can see its effects both today and in the past. For example, the book "Evolution" mentions this:
The earliest known reptiles are so amphibian-like that their assignment to one category or the other is largely a matter of opinion. In this area of life, however, there was no missing link; all the gradations from amphibian to reptile exist with a clarity seldom equaled in paleontology.
In other words, there is plenty of evidence, past and present, for some sort of evolutionary process. We see it in bacteria and insects today, and we see it in the fossil record through the development of millions of species over millions of years.
After thinking about questions like the three mentioned in the previous sections, different people come to different conclusions. In the future, there are three possible scenarios for the theory of evolution:
- Scientists will come to a complete understanding of DNA and show how mutations and natural selection explain every part of the development of life on this planet.
- Scientists will develop a new theory that answers the questions posed above to almost everyone's satisfaction, and it will replace the theory of evolution that we have today.
- Scientists will observe a completely new phenomenon that accounts for the diversity of life that we see today. For example, many people believe in creationism. In this theory, God or some other supernatural power intervenes to create all of the life that we see around us. The fossil record indicates that hundreds of millions of new species have been created over hundreds of millions of years -- Species creation is an intense and constant process with an extremely long history. If scientists were to observe the creation process occurring the next time a major new species comes into existence, they could document it and understand how it works.
Let's assume that the theory of evolution as currently stated is the process that did bring about all of the life that we see today. One compelling question is: "What happens next?" Evolution must be at work right now. Our species, Homo sapiens, only appeared about 40,000 years ago. What does evolution have in store for human beings, and how will the change manifest itself?
- Will a child appear one day whose brain is twice as big as any normal human brain? If so, what will be the capabilities of that brain, and how will it differ from the brain seen today? Or are our brains slowly evolving right now?
- Will children appear one day who have more than 23 chromosomes? If so, what will be the effects of the new chromosomes?
- Will man learn how to control or accelerate evolution through genetic engineering? Once we completely understand different genomes, will we be able to engineer evolutionary steps that lead to new species on a much faster schedule? What would those species look like? What would we design them to do?
These are all fascinating questions to think about. They reveal just how big an effect evolution can have. Given enough time, evolution could completely alter life on this planet by disposing of the species we see today and creating new ones.
For lots more information on evolution and related topics, check out the links on the next page.