On 9/10/98 -0500, Eliezer S. Yudkowsky wrote:
>I find it peculiarly coincidental that right after I published my statements
>on punctuated equilibrium, I found this paper on Eurekalert:
>
>http://www.rochester.edu/pr/releases/bio/orr.htm
>
>Orr challenges the theory that evolution consists of many tiny genetic
>mutations: "The distribution of mutations causing adaptation neatly fits an
>exponential curve: While few major mutations are needed, the number of more
>minor mutations rises exponentially with their genetic insignificance. Orr's
>theory is based on mathematical modeling and computer simulations, and assumes
>that a population is well-positioned to adapt to environmental pressures. He
>now plans to use a common laboratory technique called quantitative trait
>locus, or QTL, analysis -- capable of examining how species' genetic
>compositions differ -- to examine whether his theory holds up."
I finally obtained this paper and read it last night. It is a theory paper, and the key assumption is that "the phenotypic optimum changes suddenly and then remains fixed during the bout of adaptation studied." The paper then models a hill-climbing search to a peak. In such searches, one makes big moves early on, and then smaller and smaller moves as one approaches the peak.
The bottom line is that this paper *assumes* punctuated equilibrium, and so is not evidence in favor of it.
Robin Hanson
hanson@econ.berkeley.edu http://hanson.berkeley.edu/
RWJF Health Policy Scholar, Sch. of Public Health 510-643-1884
140 Warren Hall, UC Berkeley, CA 94720-7360 FAX: 510-643-8614