 There's a lot of confusion about what the modern theory of evolution is all about. I think a lot of people who have decided to reject it do so because of the consequences or implications of the theory. I put all the creationists who believe in the intelligent design apologetics in this category. Some of them, and I'm thinking specifically of Michael Beehe, give the impression that they fully accept every aspect of evolutionary theory, but they want to inject something else into the process. So they go hunting for some crack to inject that mechanism into. In any debate between a creationist, intelligent design, or young earth, it's worth spending a few minutes to figure out what points about evolutionary theory we disagree on. I propose the following list of points that are the basis of evolutionary theory. This is my own understanding and it probably is far from complete, but it might give people some frame of reference about where they disagree. Each of these points is supported by controlled, experimental evidence in peer-reviewed scientific papers. Point one, DNA is the basis of heredity. Point two, DNA changes over generations. Point three, DNA is responsible for the differences between organisms. Point four, the environment acts on the frequency of the changes, and point five, there is no physical limit to the amount of changes that can occur in DNA. Let me expand on each of those. Point one is simple, DNA is the basis of heredity. It's the two-dimensional representation of the three-dimensional cell. It's the simple digital code passed on from the previous generation successful reproducers. It's the general biological information flow. The DNA makes the RNA, the RNA makes the proteins, and the proteins do the work in the cell. Point two, DNA changes over generations. Much has been made about mutations, but while mutations are ultimately the source of variation, they're not really the substrate, the raw material of evolution. A point mutation is when a single nucleotide base changes. But when that mutation is passed on and becomes a part of the gene pool, biologists generally stop calling it a mutation. Once that genetic change has spread through a population, we now refer to it as a polymorphism, possibly from many more from shape. Polymorphisms are passed on, possibly for thousands of generations. If the difference is a single nucleotide, it's called a single nucleotide polymorphism, or SNP, or SNP. If the polymorphism is an insertion or a deletion of sequence, we call this an indel. This is why I find the discussion of beneficial mutations so baffling. It's diversity, not rare events, that drives the genetics of populations. It's polymorphisms, not mutations, that selection acts on. And these polymorphisms are already present in multiple forms. Evolution is just about changes in the relative quantity of each form, which we call an allele. Evolution can even be described as a change in allele frequency in a population over time. In humans, there are roughly 3 million documented SNPs. A small minority of those SNPs are known to affect your health. A developing field called pharmacogenomics, or personalized genetic medicine, will allow doctors to treat you with only the drugs that will be effective, and will allow them to select a dosage that will minimize the toxic effects. It would be impossible to classify these polymorphisms as beneficial or harmful unless we specify the context. A gene which metabolizes nitrates very rapidly would be beneficial in a high-nitrate environment by preventing toxicity, but bad in an environment where nitrate was hard to come by. In humans, for example, the MC1R gene that affects skin and hair coloration also plays a role in metabolizing some anesthetics. The polymorphisms in this gene that produce red hair color also cause the person to metabolize anesthesia at a different rate. The result is that redheads generally need about 20% more anesthesia during surgical procedures to maintain the same level of suppressed awareness. That's an important thing to know, especially for redheads and their anesthesiologists. If we look at this situation, would we say that this is a trait that is beneficial or harmful? It's hard to say, but the genetic diversity exists the moment the environment changes to act on the diversity. We would have a change in allele frequency. Over time, with enough selection pressure or other effects, we would find one of these two alleles would go to fixation and the population would no longer contain any diversity. One allele would have dominated. Point three, DNA is responsible for the difference between organisms. All vertebrates start life as a single cell. It is their differences in DNA sequence that determine whether that cell becomes a human or a chimpanzee, a sheep or a whale. In discussions of morphology and fossils, I think this has been overlooked. The eye, for example, did not evolve. Let me repeat that the physical eye did not evolve. What evolved was the information to make an eye, the DNA sequence that coded for the eye. Everyone focuses on these drastic physical changes, completely ignoring the fact that the DNA sequence changes are what is driving evolutionary change. You see this, I see this. It's worth noting that DNA sequences and the proteins they code for are highly polymorphic between species, except where there is a functional portion of the protein. In fact, that's how we've identified the most important bits of most protein by looking for conservation between species. This would seem to support the idea that the same gene in different species has an ancestor gene in common. We could certainly postulate that a designer created a lot of very similar proteins to do the exact same job, but why should we? The natural mechanisms of genetic change are just as descriptive. No new insight is created by invoking a supernatural designer to do the job. Point four, the environment acts on the frequency of the changes. We talked earlier about how the environment is capable of acting on allelic frequencies. We could call that natural selection, and that's an important driving force in changes in allele frequency. But there are other less deterministic effects. Suppose in a small population with low diversity, let's say fruit flies. A wildfire separates two groups on opposite sides of a barren stretch. One population gets a little bit more of one allele than the other. Let's say white eye allele. Over time, this population is much more likely to end up with a whole lot of white eyed fruit flies than the other population. This is known as the founder effect. Randomness is the wrong term for these kinds of effects. Non-deterministic effects are those we can't predict from the available evidence. Point five, there are no physical limits to the amount of genetic change that can occur. Human mutation rates are about one in 200 million bases. That's a pretty low probability until you consider that we have about seven billion bases per diploid genome. It works out that every human alive has statistically somewhere around 175 mutations that did not exist in either parent. There are six billion people walking around. Each of them a mutant at multiple locations. There are about a million times that number of bacteria living on a single human body. In fact, the number of bacteria living on Earth at any given time is estimated to be 10 followed by 30 zeros. And that's what's alive now. The Earth is billions of years old. A bacterial generation is counted in minutes, not years. So there's been a whole lot of reproduction going on here on Earth since life began. Numbers that most of us are simply incapable of imagining. It's no wonder that we have such a hard time imagining one form or body plan giving rise to another. We have no concept of such large numbers of deep time. But it's important to remember that every mutation that can occur probably does or has. Now, is there a limit to the amount of genetic change that can occur? Not that I'm aware of. If we get to the level of mechanism, what would prevent the next genetic change from occurring? If we want to talk about probabilistic calculations, then we have to acknowledge the actual level of genetic diversity that exists. And we have to understand how statistics of rare events work. So let's review. We have genetic material, which is inherited with variations, resulting in differences in the offspring, which is acted on by the environment. Resulting in differences in the offspring, which are acted on by the environment. This process of genetic change is repeated a few billion times, resulting in all of the genetic diversity we see today. So creationists, intelligent designer, young Earth, where do we part ways? What do I accept that you do not? I eagerly await your response.