Evolution 101

Sunday, July 02, 2006

What is the Evidence Against Evolution?

I’d like to welcome any new listeners this week. The listenership here is growing steadily, and I have to say I’m very happy that so many have such interest in evolutionary theory. I’m certainly glad to have you all on board, and I welcome any questions you may have- remember, your questions are what drive this podcast.

Speaking of which, here’s the listener e-mail for this week, from Cameron, who asks: “We know that monkey babies are soon thrown on the mothers back after birth and have to hang on, and have that ability in them at birth. If a monkey was slowly evolving to human and evolution was taking place the offspring would not likely survive considering survival of the fittest and all. While the human eventually would become superior intellectually, they at birth they are quite helpless. If it was a survival of the fittest situation the more human a monkey became the less likely they would be to survive. If I was forming a theory to find the common cause I would say that monkeys would more likely have evolved from humans based on what is known on the care of babies. The humans would care for the child the same and eventually they would evolve to the point that they did not need all the care. Can you follow the logic on this? But of course we have to deal with the fossil record and that seems to say a different story. What do you think?“

Well, Cameron, I think I follow what you’re saying. You're saying that although you accept the evolution of the species, you're having trouble accepting that natural selection can account for it all?

Well, you're right- it's not as simple as "survival of the fittest." Ultimately, of course, what it comes down to is which members of a population are able to reproduce the most efficiently- but that doesn't always mean that the strongest or fastest is the one that fits the bill.

Sexual selection, for example, is a component of natural selection that very often runs counter to what we would anticipate in terms of the selection of certain traits. Take the peacock, for example. The male of that species sports a tail that is nonfunctional (although attractive), and costs him much in terms of energy to produce. Yet we also observe that females are most attracted to males which have the largest and most impressive tails- hence the selection. I should probably do a podcast on this subject soon.

Also, remember that the "selection" component of natural selection is a composite of all the environmental factors that affect any group of organisms- or lack thereof. For example, you mention the fact that monkeys cling to their mothers, and yet humans do not. What we also know is that humans differ in a number of significant ways from monkeys, including the amount of body hair. There are a number of hypotheses to explain why humans lost body hair (neoteny is one, which I feel is pretty strong), but consider that without body hair, it was impossible for babies to grab onto their mothers. Thus, natural selection kicks in. Any mother which treated her child like a monkey would have lost it, and would not have passed on any genes. Only those mothers who slowed down to carry their babies were successful in raising them to adulthood, and thus the genes which encouraged this behavior were passed on. Or it could have been the other way around- mothers stopped carrying babies on their bodies, and thus there was no selective pressure to keep full body hair.

Whatever the reason, the molecular evidence clearly shows that humans and primates are descended from a common ancestor. Common heredity is the ONLY phenomenon that has been observed which can explain two different organisms having the same genetic information.

All right, on to this week’s topic. The intended audience of this podcast is, as I’ve made clear many times before, those with no formal scientific training- laypeople, if you will. One of the confusing things about being a layperson in regards to some esoteric topic, is that there are always “experts” on both sides of the issue that are trotted out to voice the opinions of both sides, and it’s very hard to decide which experts are the most believable. Believe me, this is true for me in a lot of subjects- I may know my way around evolution pretty well, but there are a lot of things in science of which I find myself at a complete loss.

For those people that are inexperienced with the evidence for evolutionary theory, the arguments from those promoting the position of creationism can be just as confusing, especially when the creationist scientists are trotted out to make their arguments against evolution. So- who do you listen to? Ken Miller advocates for evolutionary theory, and Michael Behe advocates for intelligent design. Both men have Ph.Ds, both men are college professors, both men have published primary scientific literature, and both men have written popular books on the topic. Both men were even called to testify at the Kitzmiller v Dover trial. So… who’s right? And, more importantly, what can we look at to see?

Well, I’ve already done a podcast on Behe’s argument for Irredicble Complexity. Essentially, he argues that certain biological systems are so complex that they could not have evolved from simpler systems, and thus he posits the existence of an intelligent designer to explain their existence. I already explained why, logically, this is fallacious, because it is an appeal to ignorance, and regardless, evolutionary theory aptly provides an explanation for the evolution of the few examples he gives. So, logically, Behe’s argument falls pretty flat. But what about scientifically?

If, as Behe hypothesizes, biological systems are, in fact, irreducibly complex, then we should be able to see overwhelming evidence from scientific investigation. This is where the rubber meets the road, basically. Anyone can have an idea, but without rigorous, scientific investigation, peer-reviewed and published, that idea is just an idea- and can not be treated with any scientific respect. So sure, Michael Behe has the same academic credentials as Ken Miller, but has he been able to put his grant money where his mouth is? In other words, what scientific papers have been published that support Irreducible Complexity? Or, for that matter, Intelligent Design or Creationism in general?

Let’s just take a brief sample- on PubMed, one of the most popular biomedical search engines, a search for “evolution” turns up 178,160 papers. A search for “creationism” on the other hand, yields only 48 articles. Most of those are editorial articles by scientists expressing the concern over the creation vs evolution debate in popular culture. There is one interesting scientific paper that comes up, published in the journal “Laterality,” which concludes that people with a strong preference for one hand versus the other are more likely to believe in creationism, whereas people who are ambidextrous, or those who can use both their right or left hand, are more likely to accept evolutionary theory. A search for intelligent design brings up the same small numbers. But aside from that, there is no published data that can be easily found, no primary data that leads to the conclusion: creationism is the accepted hypothesis.

Fortunately, the Discovery Institute (the most scientifically rigorous Creationist organization of which I'm aware) has helped to resolve this issue by publishing a list of peer-reviewed literature supporting ID. I should, before I proceed further, explain what “peer-review” means. Essentially, this means that once a paper has been written containing new hypotheses, data, and conclusions, it has to be given to one or more “peers”, i.e., other scientists who are also publishing data, preferably in a field close to the one that the paper in question deals with. According to the Discovery Institute, the reason for highlighting a “peer-reviewed” list of articles is due to the fact that “critics of intelligent design often claim that design advocates don’t publish their work in appropriate scientific literature. For example, Barbara Forrest, a philosophy professor at Southeastern Louisiana University, was quoted in USA Today (March 25, 2005) that design theorists ‘aren’t published because they don’t have scientific data.’”

Well, let’s see the data!

They begin by showing seven "featured" articles. However, all of them are reviews, or position papers. None of them contain any basic research, and I'm unsure why they would want to "feature" them. Most of them are published in "Proceedings of" journals, which have a slightly different peer review process than other journals. Basically, as long as you can get a member of that particular society to sponsor your paper, it'll be published. The one contribution by Jonathan Wells would seem to be interesting, in that it proposes an experiment, but doesn't actually carry it out. I can't find any follow up papers, and it appears that it was just an abstract that was presented at a conference.

They likely realize that seven articles, none of which present any basic research, seems kind of weak, so they fill out the list categorically, starting with four "peer-reviewed" books. I'm not completely sure how these University presses work, but I very much doubt its anything similar to the review process for scientific articles. There's also three books that are "supportive" of ID, although not peer-reviewed (again, what does that mean?)

And finally we're down to the real meat, articles published in peer-reviewed scientific journals. Here we're down to six, only two of which were "featured" above. The first is in the journal "Chaos, Solitons, and Fractals." The second is in a "Proceedings" journal, and actually caused quite a stink from that society towards the editor who allowed its publication. The third is actually by Behe and is from a respectable journal, Protein Science, although it received a lengthy rebuttal in that same journal which basically showed that they had made several mistakes in assumptions for their calculations (Behe had tried to use mathematical modeling to show that mutations couldn't accrue fast enough to result in modification).The fourth is a review that questions the relevance of transposons to evolution (but not supportive of ID).The fifth is published in the "International Journal of Fuzzy Systems." And the last is in the "Journal of Theoretical Biology," postulating that the limited and predictive arrangement of protein folds represents a manifestation of "Natural Law," as opposed to "natural selection." This is not contary to evolutionary theory, however, since evolution does not predict that chemical interactions between amino acids change over time, just the arrangements of amino acids in a peptide chain, in response to varying levels of environmental selection.

Following these is a list of seven articles published in "peer reviewed" anthology books, five of which were published by members of the Discovery Institute. And then they have another seven "peer-edited" articles, four of which were also written by DI members. And they round it off with five philosophical papers, (with the guarantee of no basic research) one by Behe and the rest by William Lane Craig.

So that's it. The most the Discovery Institute can muster is 26 articles (none with a single experiment) and four books. As a point of contrast, remember there are 178,160 articles (25,672 of which are reviews) on PubMed which involve evolution (and that only goes back to 1916).

I want to repeat- not a single experiment has been published to test a hypothesis advanced by creationism or intelligent design. Not a single one. So sure, there are definitely scientists with real degrees out there, talking about intelligent design, but they can’t perform a single experiment to back up their arguments. Remember that next time you find yourself torn between two “experts” in the creationism/evolution debate. Firstly, there is no scientific debate on the subject- we can see that in the constant and overwhelming asymmetry of papers published in support of evolution versus those published in support of creationism. When less than 0.01% of the papers published on a topic are in support of an alternative explanation, you can pretty much guarantee that there’s no debate. And secondly, there’s just no evidence to support any other hypothesis but evolution. Not a single experiment. Which makes complete sense, of course- how can you hope to conduct an experiment to test a phenomenon which is, ultimately, supernatural? Those who would deny the fact of evolution know this, which is why the only arguments they can hope to get away with are those that attempt to discredit evolutionary theory. Remember- if an “expert” has no direct evidence in support of his own position, but can only attempt to tear down the opposing position, you can reasonably conclude that he doesn’t have anything meaningful to offer.

So, in conclusion, evolutionary theory is the only explanation for the data that is available to us, and no alternative hypothesis (creationism, intelligent design, etc) even has the power to propose a single experiment which could support it. I think it should be pretty clear now that, for those inexperienced with evolutionary theory, choosing the experts to listen to should be a no-brainer. Thanks for listening, and take care.


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