I once attended a lecture by American creationist, Duane Gish. During the lecture, Gish made fun of biologists’ theory that whales descended from land animals related to cows. How, he asked, could such a transition occur, since the intermediate form [“missing link”] would have been poorly adapted to both land and water, and thus couldn’t be built by natural selection. To illustrate his point, Gish showed a slide of a mermaidlike cartoon animal whose front half was a spotted cow and whose rear half was a fish. Apparently puzzled over its own evolutionary fate, this clearly maladapted beast was standing at the water’s edge, a large question mark hovering over its head. The cartoon had the intended effect: the audience burst into laughter. How stupid, they thought, could evolutionists be?
“It’s an udder failure!” said Gish.
Let’s forget the jokes and look to nature. Can we find any mammals that live on both land and water, the kind of creature that supposedly could not evolve [according to creationists]?
Easily. A good candidate is the hippopotamus, which, although closely related to terrestrial animals, is about as aquatic as a land mammal can get. Hippos spend most of their time submerged in tropical rivers and swamps, surveying their domain with eyes, noses, and ears that sit atop their head, all of which can be tightly closed under water. Hippos mate in the water, and their babies, who can swim before they can walk, are born and suckle underwater.
…Hippos are obviously well adapted to their environment, and its not hard to see that if they could find enough food in the water, they might eventually evolve into totally aquatic, whalelike creatures.
But we don’t just have to imagine how whales evolved by extrapolating from living species. Whales happen to have an excellent fossil record, courtesy of their aquatic habits and robust, easily fossilized bones. And how they evolved has emerged within only the last twenty years. This is one of our best examples of an evolutionary transition [“missing link”], since we have chronologically ordered series of fossils, perhaps a lineage of ancestors and descendants, showing their movement from land to water.
It’s been recognized since the seventeenth century that whales and their relatives, dolphins and porpoises, are mammals. They are warm-blooded, produce live young whom they feed with milk, and have hair around their blowholes. And evidence from whale DNA, as well as vestigial traits like their rudimentary pelvis and hind legs, show that their ancestors lived on land. Whales almost certainly evolved from a species of artiodactyls: the group of mammals that have an even number of toes, such as camels and pigs. Biologists now believe that the closest living relative of whales is—you guessed it—the hippopotamus.
So maybe the hippo-to-whale scenario is not so far-fetched after all!
–biologist Jerry Coyne, Why Evolution is True, pp. 47-49
End of post.