Natural Selection

In my reading today of Jerry Coyne’s Why Evolution Is True, the topic was natural selection. According to natural selection, organisms with certain beneficial (or useful) characteristics live to pass on the genes for those characteristics to offspring. As a result, more organisms with those characteristics emerge. That’s why there are more white mice than black mice in areas with white sand: the white mice survive long enough to pass on their genes, because they’re able to blend in with their surroundings and protect themselves from predators. They then live on to produce more white mice.

What is the origin of these beneficial characteristics? According to Coyne, the answer is “mutation”. There are creationists who have argued that most mutations are harmful or inconsequential. Coyne concedes that point. But Coyne points out that there are times when a mutation can be beneficial. Those beneficial mutations are what Coyne calls “The Engine of Evolution”.

Coyne talks about viruses, which mutate and evolve to protect themselves against vaccines. This does not always occur, for “there are some spectacular cases of microorganisms that haven’t succeeded in evolving resistance” (page 131). As Coyne states, “We must remember that the theory of evolution doesn’t predict that everything will evolve: if the right mutations can’t or don’t arise, evolution won’t happen.” But there are times when a beneficial mutation (beneficial at least for the microorganism, not us) does occur.

As I’ve blogged through Coyne’s book, I’ve consulted what the creationist organization Answers in Genesis has to say. What does Answers in Genesis say about viruses that evolve to protect themselves from vaccinations? In the article, Bird Flu – Has It Evolved? , Dr. Ryan Kitner (who has a Ph.D. in genetics from Clemson University, in South Carolina) states the following:

The word evolution has certainly been given a biological stigma in the last century. It’s hard to use “evolve” in any biological context without it being interpreted in the Darwinian sense of the term. So, are the mechanisms that bird flu uses to spread and escape extermination considered evolution? It is plain to see that the genetic code of bird flu viruses does not stay the same but is constantly mutating and rearranging. Because virus proteins interact with proteins in the cells they infect, changes in the viral protein can and do have effects on what type of cells can be infected and how it affects the host.

So what should one say if asked, “Is the ‘bird flu’ evolving?” It could be said that the bird flu is continually changing and modifying, but not in the Darwinian sense that it will at some point become something other than an influenza virus (i.e., it is not evidence that particles can turn into people). Yes, influenza viruses do possess a certain degree of genetic “wiggle room.” However, the amount of genetic information that a virus can carry is extremely limited, and so are the changes that can be made to its genome before it can no longer function.

While there are creationists who argue that most mutations are harmful, making evolution unlikely, there are also creationists who contend that micro-evolution occurs, but there’s no evidence for macro-evolution. As Fred John Meldau says in his book, Why We Believe in Creation Not Evolution, there are mutations, but no transmutations. Sure, they argue, organisms can mutate within their species (or maybe it’s their genus), but they can’t become something entirely different. In the case of the Bird Flu virus, Dr. Kitner affirms that it has mutated in its genetic code, allowing it ”to spread and escape extermination.” But it’s still a virus, not something else.

But why can’t an organism mutate and, over a long period of time, become something else? I don’t see why that’s impossible.

Another question I had: How would creationists account for the ability of viruses to mutate and protect themselves? Why would God make things this way? Was he playing a cruel joke on humans? I didn’t find an article that tackled this question head-on, but I did encounter one entitled, Why Did God Make Viruses?, by Dr. Jean Lightner (whose alma mater I could not find, but her biography states that she worked as a veterinary medical officer for the U.S. Department of Agriculture). Her argument is that viruses could have had a useful function, and that’s why God created them. Here are some quotes from her article:

If God created everything good and with a purpose, why are there disease-causing bacteria and viruses in the world? It is true that we first learned about bacteria and viruses because of the problems they cause. Bacteria have been studied in considerable detail and are now recognized to be mainly helpful and absolutely essential for life on earth; bacteria that cause disease (which occurred as a result of the Fall) are the exceptions, not the rule. But what about viruses: what purpose could they possibly have?

Viruses vary considerably in their ability to cause disease. Many known viruses are not associated with disease at all. Others cause mild symptoms that may often go undetected. Some, like the HIV virus that causes AIDS in people, appear to have come from another species where they do not cause disease. Given our current knowledge of viruses, it is quite reasonable to believe that disease-causing viruses are descended from viruses that were once not harmful.⁷ It has been suggested that they have played an important role in maintaining life on earth—somewhat similar to the way bacteria do.⁸ In fact, they may play a role in solving an intriguing puzzle that faces creationists.

Interestingly, there are some portions of DNA in animals that look like they came from a virus. While some of these were likely originally present in the genome since they have essential functions, others may have been introduced by viruses.²³ A number of years ago, one creationist proposed that horizontal gene flow (genes picked up from somewhere in the environment rather than inherited from parents) may help to explain rapid adaptation and the interesting pattern of DNA in animals. In fact, the author lists 13 different biological phenomena that might be explained by horizontal gene flow.²⁴ Since viruses carry genetic material (DNA or RNA), they are the most logical agents to suspect in transferring genes. While horizontal gene transfer would not change the identity of an animal (i.e., it would still belong to the same kind), it could rapidly provide a source of genetic variability that allows for rapid adaptation. If this is the case, then viruses were created “good” (as in Genesis 1) with a support role much like bacteria are known to have. While the evidence is largely circumstantial, further scientific investigation does seem to support these ideas.

You can read more of the article to see the evidence that she cites for her claim. But what I’m getting from this is that viruses can help animals to adapt rapidly. And, by the way, Dr. Lightner holds that the existence of rapid adaptation in certain animals undercuts the theory of evolution, which maintains that adaptation is a slow process. But do evolutionists necessarily prescribe a set pace for adaptation, as if it always has to be slow and gradual? Coyne and others have pointed to the virus as an example of evolution in action, and it evolves rather quickly.