EVIDENCE FOR EVOLUTION

First consider the evidence in support of the evolutionary theory. There are two principal bodies of evidence which can be used in support of the theory of evolution. They are:

1. Genetics 2. The fossil record

This is an oversimplification, but sufficient for a starting point. Contrary to popular belief, genetics supply the strongest evidence in support of evolution. Those who would seek to “disprove” evolution typically attack the evidence from the fossil record rather than that from genetics. The goal here is not to attack or even to disprove evolution. However, any attempt to do either should discuss the genetic evidence in support of evolution.

The basic idea of genetics is that each generation of a species inherits its traits from its parent or parents through the DNA molecules contained in its chromosomes. When biologists analyze the

Where Did I Come From? 125 DNA in mammals, for example, they find that all mammals have similar DNA, providing strong support for the idea that the different species of mammals are all genetically related, and therefore perhaps all evolved from some original “mammal.”

The logical implication of evolution is that species which are closely related by descent should have similar DNA. This law, although perhaps not perfectly adhered to, generally proves true. For example, The DNA in chimpanzees has about a 99% similarity to that of humans. Logically (at least according to the logic of evolution), crocodiles should have DNA less similar to that of humans than chimpanzees to humans. On the other hand, ostriches should have more similarity in their DNA to hummingbirds than to lobsters. When the DNA evidence is examined, although there might be some interesting surprises, the general implications of evolution for genetics prove true.

To those who are emotionally tied in to the idea that Adam and Eve were created (the author would count himself among them) this sort of information may incite a reaction. Facts are facts however, and the fact is that studies of the DNA in plants and animals, at least on the surface, is consistent with the theory of organic evolution.

The second chief type of evidence called upon to support the evolutionary theory is from the fossil record. It is interesting that although the science of genetics was developed by Gregor Mendel in 1865, at about the same date as the original edition of Darwin’s Origin of Species, his theory of genetics was not generally given serious consideration until the early twentieth century. Therefore, Darwin did not use the evidence from genetics to support his theory at all. He primarily referred to the evidence from the fossil record as well as the apparent adaptation of living species to their environment. To quote Darwin:

The great principle of evolution stands up clear and firm, when these groups of facts are considered in connection with others, such as the mutual affinities of the members of the same group, their geographical distribution in past and present times, and their geological succession. It is incredible that all these facts should speak falsely. He who is not content to look, like a savage, at the phenomena of nature as disconnected, cannot any longer believe that man

is the work of a separate act of creation.2 _{(emphasis added)}

By “geological succession,” Darwin means from fossil evidence. Darwin is claiming here, and evolutionists have followed his lead, that when one looks at the fossil evidence, one will find a gradual change from more ancient species to more modern ones. This is illustrated by the familiar evolutionary family tree which will show for example, mammals and birds evolving from reptiles, which in turn evolved from amphibians, which evolved from fish and so forth back to the most ancient single-cell ancestors.

Creationists have certainly cried foul at this point: but not just creationists. Legitimate science has often and consistently called into question this claim, asking for evidence of missing links and certain hard-to-imagine in-between evolutionary forms. A statement of the famous orator William Jennings Bryan given at the Scopes trial, although perhaps a bit overstated, would represent this view:

Today there is not a scientist in all the world who can trace one single species to any other, and yet they call us ignoramuses and bigots because we do not throw away our Bible and accept it is proved that out of two or three million species not a one is traceable to another. And they say that evolution is a fact when they cannot prove that one species came from another, and if there is such a thing, all species must have come, commencing as they say, commencing in that one lonely cell down there in the bottom of the ocean that just evolved and evolved until it got to be a man. And they cannot find a single species that came from another, and yet they demand that we allow them to teach this stuff to our children, that they may come home with their imaginary family tree and scoff at their mother’s and father’s Bible.

The question of succession of species and the related question of missing links is a difficult one, but the evolutionist would defend their position as follows. Yes, it is true that the succession of separate species cannot be demonstrated in the laboratory, and yes it is true that significant “gaps” in the fossil record exist. Nevertheless, with the passage of time and as the body of evidence increases, new data

Where Did I Come From? 127 consistently tends to fill in the gaps and to support the general claims of evolution. If the theory of evolution were without any validity, then one might assume that as evidence is collected it would tend to make the theory less and less believable. The converse is true. With increasing data, the theory of evolution has in general become more plausible, not less.

To conclude this brief exposition on the data in support of evolution (remember that there are significant questions to be asked of the evolutionary theory as well, some of which will be presented presently), the fact is that the chief predictions of the evolutionary theory are more or less consistent with known fact. As data continues to come in, rather than providing more reason to doubt evolution, it tends to support it. Notice the word tends is used here, because it will be shown that there is a significant body of evidence which calls into question many of the assumptions of the evolutionary theory.