Monday, May 23, 2005

Michael Lynch Chimes In.

Michael Lynch has written a must read Nature letter on the ID article. Here are some of his best points:

"Two factors have facilitated the promotion of ID. First, IDers like to portray evolution as being built entirely on an edifice of darwinian natural selection. This caricature of evolutionary biology is not too surprising. Most molecular, cell and developmental biologists subscribe to the same creed, as do many popular science writers. However, it has long been known that purely selective arguments are inadequate to explain many aspects of biological diversity . . . But features of the genome, such as genomic parasites or non-coding introns, which aren't so evolutionarily favourable (nor obviously 'intelligent' innovations), can be more readily explained by models that include random genetic drift and mutation as substantial evolutionary forces.

. . .

"Less widely appreciated is that evolution has long been the most quantitative field of biology, well grounded in the general principles of transmission genetics. Yet few students at university, and almost none at high school, are exposed to the mathematical underpinnings of evolutionary theory. The teaching of evolution purely as history, with little consideration given to the underlying mechanisms, reinforces the false view that evolution is one of the softer areas of science.

"Here is a missed opportunity. Our failure to provide students with the mathematical skills necessary to compete in a technical world is a major concern in the United States. Mathematics becomes more digestible, and even attractive, when students see its immediate application. What better place to start than with the population-genetic theory of evolution, much of which is couched in algebraic terms accessible to school students?"

I don't know if I'd go much beyond simple transmission genetics (i.e., Punnett squares) and the Hardy Wienberg equation in a high school biology class. I've taught senior biology majors that had a hard time grasping these simple concepts. Even though the mathematics are simple -- nothing more than basic algebra -- many of the concepts are abstract and difficult to grasp for some students. Students oftentimes have a difficult time understanding what the Hardy-Weinberg theorum is testing and how to interpret the results.

Lynch's point, however, is extremely important: it should be made clear that evolutionary biology (specifically evolutionary genetics) is one of the most quantitative fields in biology, and evolutionary biology is not a "soft science."

3 Comments:

At 11:09 AM, Anonymous Reed A. Cartwright said...

So true. As Marc Feldman from Stanford told my department in a seminar a couple years ago, evolutionary biology is not only the most mathematical part of biology, but one in which there is usually robust theory in place before there are observations to apply it to.

 
At 4:51 PM, Blogger Razib said...

the only thing i would dispute lynch about is the idea that developmentalists fixate on natural selection...they seem to be on the forefront of rejecting a pure selectionist paradigm.

 
At 6:12 PM, Blogger RPM said...

I think Lynch is working from a stereotype from the mid to late 90's. I'd argue that many molecular & cell biologists tend to think of evolution with a predisposition for purifying selection. They look for pathways and molecules that are conserved between taxa and are, therefore, functionally important. I do often hear, however, many cell biologists refer to a system that has evolved some function due to natural selection.

It is true that Developmental biologists are moving toward some "non-Darwinian" revolutionary ideas. For instance, developmental characteristics can be influenced by the environment and may have limited heritibility. These concepts must be reconciled with the traditional view of selection acting on heritable variation.

 

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