Thursday, November 15, 2012
Religion vs. Science, the Vast Gulf Part Seven: Genetics
First, a couple of announcements. First, you don’t want to miss my new Darwin video in which Darwin uses a hookah pipe as an advanced piece of scientific research equipment and for hypothesis testing. Second, my website no longer has original essays, though the previous ones are still archived; I wish to move my essays to my blogs, mostly to this one. The website is now mostly a clearinghouse of links to other things. Now on with the new topic: the Bible and genetics.
The Bible presupposes that characteristics that an organism acquires during its lifetime can be passed on to its offspring. In so doing, the Bible is no different from what everybody, including scientists, thought until a little over a century ago. But to a creationist literalist, the Bible cannot be wrong about something even if every human being was wrong about it until almost two thousand years after the last of the Bible was written.
The most noticeable example of “Biblical Lamarckism” is in the story of Jacob and Laban in the book of Genesis. Jacob was if anything very tricky. He tricked his brother Esau out of his birthright. And he tricked his relative Laban out of some goats too. Jacob was shepherding Laban’s goats, and made a deal: Jacob would get to keep all of the speckled goats, while Laban got to keep the pure white and pure black goats. Sounds like a deal, Laban said. But Jacob had a plan. (He almost always had a plan, except one night when he was terrified of having to face Esau, his defrauded brother, the next day.) Each evening the goats would come to the water trough to drink and to copulate. (Mommy, what does copulate mean? Be quiet and read your creationist book.) Jacob set up a little wall made of alternating dark and light boughs. The goats would see the striped pattern and have striped offspring, which Jacob got to keep. The clear implication is that the goats had striped and speckled offspring because they saw the stripes at the trough. This is a clear Biblical teaching of Lamarckism. Most of us interpret this to mean that Jacob just thought that the goats had striped offspring because they saw the stripes. But the clear implication in the story is that seeing the stripes caused the offspring to be striped. Creationists ought to have trouble with Mendelian genetics.
There is an easy Mendelian explanation for what happened. The genes from the black goats and from the white goats mixed to form striped and speckled goats. That is, the black and white goats were homozy-goats and the striped goats were heterozy-goats. But this is what science, not what Genesis, says.
The ancient Hebrews also had a very limited idea of what we today call genetic variation. They did not know about many species of animals, or different races of people. They knew about “Ethiopians,” but did they have any idea about the blonds and redheads up north? For aught they knew to the contrary, all genetic variability within each animal species could be contained within a pair of animals on Noah’s Ark, and all human diversity could be contained within Noah’s family. But we know that each species of animals (and everything else) has more genetic variation than could possibly be contained within two individuals, even if God chose the two most diverse and different individuals (for example, two animals of genotypes A1A2 and A3A4 for gene A). No more than four alleles for each gene could be so preserved to account for the whole world of diversity within each species. Modern creationists get around the human problem by claiming that Noah’s daughters-in-law were black, oriental, and white. The Bible mentions nothing of the sort (although it sounds like a good premise for a sitcom), but creationists have never been hesitant to make stuff up about God.
If I may stray a moment from the topic of genetics, I might mention that Biblical biogeography is also wonderfully strange. All the animals debarked from Mt. Ararat in what is now Turkey, and somehow most of the marsupials went to Australia, except for Pogo the Possum, who always had to be different from the others and went to North America. This is just one example. There are hundreds of examples of animals—and plants too—whose geographical distribution looks as if the taxonomic orders and families of which they are a part evolved in the locations where they now reside, rather than migrating there from Ararat. In his book The World That Perished, the father of flood theology John C. Whitcomb answered the question of why the marsupials all went to Australia. He said, in effect, they hopped.
The ancient Hebrews did as good a job as anyone else at figuring out how traits passed from one generation to another. They did as good a job as Darwin, whose pangenesis theory is almost painful to read—such a wrong theory from a man who got almost everything right. But you cannot base the science of genetics on what the Bible says. Darwin did do one thing much better than the ancient Hebrews, however. He extensively studied the genetic (“heritable”) variation in plant and animal species, and knew that there was a lot more of it than met the eye. This was the basis of natural selection.