Over the last few days, I have had a few, um, discussions with creationists, as much as that is possible with such dogmatic people. They keep trying to tell me that my professional life investigating the history of life has been a lie and that all the evidence I have seen doesn’t exist. Even when they get into a discussion of science they usually demonstrate they have almost no understanding of how science operates.
Creationists, and the proponents of the modern watered-down version, intelligent design, are adamant that there is no evidence for evolution whatsoever. While some of the questions they ask are simply idiotic1, other questions simply demonstrate their ignorance of both the fact of evolution, as well as its mechanism.
Evolution basically refers to the change in the earth’s biota over time. We have the fossil record which demonstrates that exceptionally clearly. While it was still able to be debated when the understanding of the fossil record was in its infancy, even by the time of Charles Darwin the fossil record of the last 540 million years was fairly well understood. Darwin had great concerns about the fossil record in rocks older than that, because there seemed to be no fossils at all in what was termed the Precambrian (prior to the Cambrian; i.e. older than 540 million years ago). However, the increase in understanding of the fossil record has continued apace. We now know that there are an enormous number of fossils in Precambrian rocks. It’s just that most of them are microscopic, and very few microscopic fossils were known in Darwin’s time. Indeed, we now have undisputed evidence of life on earth (in Western Australia) from as long ago as 3,480 million years ago2,3. That is the fact of evolution.
Often you will hear creationists state that they think evolution cannot be true, but in this they are conflating the fact of evolution with its proposed mechanism. Its mechanism is what Charles Darwin termed ‘natural selection’. It is explained very simply, but is an enormously complex system. Basically, members of a species vary genetically, and depending on the environment in which they live, this can lead to a difference in reproductive success (i.e. number of offspring) of individuals, with the consequent preferential survival of lineages with a more beneficial genetic makeup.
Creationists are so ignorant that they mostly seem to believe that evolution is dependent upon the variation caused by single point mutations in a gene, like the one that is causes blue eyes in humans. This is caused by a single mutation on the OCA2 gene on the long arm of Chromosome 154. However, this sort of mutation, a single base-pair substitution, is the small tip of a very large iceberg of variation. Others include: an insertion or deletion of a single stretch of DNA; and structural variation (typically used to describe genetic changes over larger DNA sequences, including copy number variation and chromosomal rearrangement). Each of these has numerous variants5and includes the duplication of whole genomes. All flowering plants have at least one genome duplication in their evolutionary history6. This, of course, is something that creationists either do not know or do not want to know.