As a teacher I've learned that students learn best when they are able to do something for themselves, and see for themselves that some particular thing is right or wrong. Active learning is many times more effective than passive learning, but it presupposes that the student actually wants to learn. Unfortunately, many teachers assume that their students want to learn when they're actually comfortable with not learning.
I will not make that mistake. Montalban may have passed up an opportunity for active learning but that won't stop me from teaching him a lesson, anyway.
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Malaria and sickle-cell anemia are endemic to sub-Saharan Africa. Malaria is a mosquito-borne disease caused by trypanosomes, which are protozoan parasites whose life cycle includes a phase of digesting human red blood cells. Sickle-cell anemia is a congenital disease caused by a single SNP in a hemoglobin gene; individuals homozygous for the sickle-cell anemia allele have abnormal "sickling" hemoglobin that tends to over-polymerize, rendering red blood cells unusable.
The sickle-cell anemia allele is, after a fashion, recessive: that is, a heterozygous individual will only have sickle-cell
trait, which is a far milder pathological condition, as this individual will have both normal and sickling hemoglobin in his or her red blood cells. However, sickle-cell trait confers higher tolerance of malaria, since the malarial parasites' life-cycles are also inhibited by the abnormal form of sickling hemoglobin.
It comes as no surprise that sickle-cell trait is widespread (~25%) in the sub-Saharan populations where malaria is prevalent. Indeed, in America, the prevalence of sickle-cell anemia among those of sub-Saharan descent is
ten times the general populational prevalence. However, sickle-cell trait is also widespread in some Mediterranean areas, where malaria is not endemic - or at least isn't endemic
now. But malaria used to be more common in those areas before Europeans learned how to fight it, and the genetics of these populations are only now changing to reflect the fact that malaria is no longer a threat.
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Montalban is quite right to say that there is no such thing as "nature" which "selects" for one trait against another. After all, the malarial trypanosome is as much a part of "nature" as the sickling hemoglobin in humans. But in doing so, he has misunderstood the term "natural selection" as much as he possibly could: that is, he has misunderstood the word "natural", and he has misunderstood the word "selection".
He is conflating the two meanings of "natural". Natural can mean simply "of Nature"; but it also means the opposite of "artificial".
So, shernren has a
natural knack for bending over backwards to teach people who don't even want to learn. This doesn't mean that there is some entity "Nature" which causes shernren to teach recalcitrant creationists; rather, it means that shernren teaches recalcitrant creationists all on his own, without some other evolutionist - mallon or gluadys, say - telling him to do so. In this case, a human intentional action is actually "natural", because it isn't artificial.
He has also conflated the two meanings of "selection". Selection can refer to the intent of the selector, or to the demographics of the selected objects.
So, for example, a minor league baseball coach wants players who are strong over players who are weak. Therefore, he
selects strong players. But he also unconsciously
selects players who are born in the month of August. Now, did he
want August babies in particular as compared to any other birth month? Clearly not; and yet, since his outcome consists of a disproportionate number of August babies, it is quite accurate to say that the coach has selected more August babies than normal, even if he didn't want to.
Now, is there a "Nature" entity that causes sickle-cell trait to be prevalent in sub-Saharan Africa? Of course not. But there is
an actual entity that causes this to happen - the malarial trypanosome. The effect of the malarial trypanosome is "natural", not because it is caused by "Nature", but because it happens without artificial intervention.
And does the malarial trypanosome actually
want the sickle-cell trait to be prevalent? Was there a Protozoan Committee which decided on a list of desirable characteristics for humanity to have or not have? (And when they couldn't agree, voila! The Cambrian Explosion.) Of course not. And yet, the action of malarial trypanosomes is such that a population which undergoes malarial infestation comes out at the other end with a higher proportion of sickle-cell trait carriers. Even though there is no conscious
act of selection, there is still an
effect of selection.
This second point bears repeating because it is insidious. Sieves do not
want flour particles smaller than a certain radius to pass through it. Tsunamis do not
want to only destroy weak buildings (and this is a Biblical example). MLB coaches do not
want August babies. Employers do not
want to employ highly-educated people (they want people who will maximize the profit per salary spent). And yet, in all these cases,
selection occurs even without
selective intent.
So, in short, natural selection is not Nature's act of selecting, but the natural effect of selecting. And if Montalban cannot grasp even that, then he has no business teaching logic to anyone, let alone to evolutionists.
