tag:blogger.com,1999:blog-6410615559824660051.post2967066747532734498..comments2023-10-18T05:31:21.249-07:00Comments on Peregrinations: Lactose ToleranceRick Gerhardthttp://www.blogger.com/profile/10478878021692544533noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-6410615559824660051.post-38362254241423925692008-09-28T03:45:00.000-07:002008-09-28T03:45:00.000-07:00Dear Mr Gerhardt,Thank you for this interesting bl...Dear Mr Gerhardt,<BR/><BR/>Thank you for this interesting blog entry. As an (evolutionary) biologist and someone with a particular interest in the relationship between science and society, I take a great interest in the arguments of young earth creationists and those who oppose naturalist evolution.<BR/><BR/>I have a number of problems with what you have written, but feel compelled to interject regarding one key point, if you do not mind.<BR/><BR/>I refer you to your words:<BR/><BR/>"We are meant to believe that those who still could not drink milk (without developing a rash on the inside of their elbows) died before having children, while this one adaptation endowed the milk drinker with overwhelming survivorship and productivity. In other words, environmental factors somehow dictated that the ability to process milk efficiently was the make-or-break characteristic for this population of humans (though they had been surviving and reproducing up until that point)."<BR/><BR/>I am afraid you have made a fundamental error, albeit a very common one. Natural selection does not primarily act at the level of the population. The authors of this paper would almost certainly not claim that lactose tolerance would spread throughout the population for this reason. Rather (and you make the point yourself very well elsewhere):<BR/><BR/>“On the naturalistic evolution view, this adaptation is so significant that his ability to survive and reproduce so exceeds that of others of his generation and clan that his progeny soon outnumber theirs by 10 to 1.”<BR/><BR/>I am not sure how you come up with your subsequent argument (earlier quote), given this earlier explanation that it is differences between reproductive successes of individuals within populations. Perhaps you have not considered how lactose tolerance could increase reproductive success of individuals within a population relative to others? If an individual’s fitness were improved even slightly by his or her ability to exploit such a food resource, then any gene conferring such an advantage should spread. It wouldn’t have to make the difference between life and death in all cases. It would merely need to confer a slight advantage on average. We don’t need to consider all the ways in which the availability of milk could be even slightly beneficial. It’s not a great stretch of the imagination.<BR/><BR/>A herding population with wholesale lactose-tolerance may well have outcompete a herding population with wholesale lactose-intolerance. But this is not what would lead to the first population being tolerant in the first place. Slight differences between reproductive successes of individuals within populations are always what will matter the most.<BR/><BR/>Thanks<BR/><BR/>IanAnonymousnoreply@blogger.com