Why Darwin Matters_ The Case Against Intelligent Design - Michael Shermer [13]
2. Male uterus. Men have the remnant of an undeveloped female reproductive organ that hangs off the prostate gland for the same reason.
3. Thirteenth rib. Most modern humans have twelve sets of ribs, but 8 percent of us have a thirteenth set, just like chimpanzees and gorillas. This is a remnant of our primate ancestry: We share common ancestors with chimps and gorillas, and the thirteenth set of ribs has been retained from when our lineage branched off six million years ago.
4. Coccyx. The human tailbone is all that remains from our common ancestors’ tails, which were used for grasping branches and maintaining balance.
5. Wisdom teeth. Before stone tools, weapons, and fire, hominids were primarily vegetarians, and as such we chewed a lot of plants, requiring an extra set of grinding molars. Many people still have them, despite the smaller size of our modern jaws.
6. Appendix. This muscular tube connected to the large intestine was once used for digesting cellulose in our largely vegetarian diet before we became meat eaters.
7. Body hair. We are sometimes called “the naked ape”; however, most humans have a layer of fine body hair, again left over from our evolutionary ancestry from thick-haired apes and hominids.
8. Goose bumps. Our body hair ancestry can also be inferred from the fact that we retain the ability of our ancestors to puff up their fur for heat insulation, or as a threat gesture to potential predators. Erector pili—“goose bumps”—are a telltale sign of our evolutionary ancestry.
9. Extrinsic ear muscles. If you can wiggle your ears you can thank our primate ancestors, who evolved the ability to move their ears independently of their heads as a more efficient means of discriminating precise sound directionality and location.
10. Third eyelid. Many animals have a nictitating membrane that covers the eye for added protection; we retain this “third eyelid” in the corner of our eye as a tiny fold of flesh.
Evolutionary scientists can provide dozens more examples of vestigial structures—let alone examples of how we know evolution happened from all of these other various lines of historical evidence. Yet as a science, evolution depends primarily on the ability to test a hypothesis. How can we ever test an evolutionary hypothesis if we cannot go into a lab and create a new species naturally?
I once had the opportunity to help dig up a dinosaur with Jack Horner, the curator of paleontology at the Museum of the Rockies in Bozeman, Montana. As Horner explains in his book Digging Dinosaurs, “paleontology is not an experimental science; it’s an historical science. This means that paleontologists are seldom able to test their hypotheses by laboratory experiments, but they can still test them.”27 Horner discusses this process of historical science at the famous dig in which he exposed the first dinosaur eggs ever found in North America. The initial stage of the dig was “getting the fossils out of the ground.” Unsheathing the bones from the overlying and surrounding stone is backbreaking work. As you move from jackhammers and pickaxes to dental tools and small brushes, historical interpretation accelerates as a function of the rate of bone unearthed. Then, in the second phase of a dig, he gets “to look at the fossils, study them, make hypotheses based on what we saw and try to prove or disprove them.”
When I arrived at Horner’s camp I expected to find the busy director of a fully sponsored dig barking out orders to his staff. I was surprised to come upon a patient historical scientist, sitting crosslegged before a cervical vertebra from a 140-million-year-old Apatosaurus (formerly known as Brontosaurus), wondering what to make of it. Soon a reporter from a local paper arrived inquiring of Horner what this discovery meant for the history of dinosaurs. Did it change any of his theories? Where was the head? Was there more than one body at this site? Horner’s answers were those of a cautious scientist: “I don’t know yet.” “Beats me.” “We need more evidence.” “We’ll have to wait and see.” It was historical