The Case for a Creator - Lee Strobel [20]
“Absolutely not,” came his quick reply. “As an illustration of the fossil record, the Tree of Life is a dismal failure. But it is a good representation of Darwin’s theory.
“You see, he believed that if a population was exposed to one set of conditions, and another part of the population experienced other conditions, then natural selection could modify the two populations in different ways. Over time, one species could produce several varieties, and if these varieties continued to diverge, they would eventually become separate species. That’s why his drawing was in the pattern of a branching tree.
“A key aspect of his theory was that natural selection would act, in his own words, ‘slowly by accumulating slight, successive, favorable variations’ and that ‘no great or sudden modifications’ were possible.”
I didn’t want to miss the significance of what Wells was claiming. “You’re saying that the tree of life illustrates Darwin’s ideas but that his theory is not supported by the physical evidence scientists have found in fossils?”
“That’s right,” he continued. “In fact, Darwin knew the fossil record failed to support his tree. He acknowledged that major groups of animals—he calls them divisions, now they’re called phyla—appear suddenly in the fossil record. 23 That’s not what his theory predicts.
“His theory predicts a long history of gradual divergence from a common ancestor, with the differences slowly becoming bigger and bigger until you get the major differences we have now. The fossil evidence, even in his day, showed the opposite: the rapid appearance of phylum-level differences in what’s called the ‘Cambrian explosion.’
“Darwin believed that future fossil discoveries would vindicate his theory—but that hasn’t happened. Actually, fossil discoveries over the last hundred and fifty years have turned his tree upside down by showing the Cambrian explosion was even more abrupt and extensive than scientists once thought.”
That begged for further explanation. “Elaborate on the Cambrian explosion,” I said.
“The Cambrian was a geological period that we think began a little more than 540 million years ago. The Cambrian explosion has been called the ‘Biological Big Bang’ because it gave rise to the sudden appearance of most of the major animal phyla that are still alive today, as well as some that are now extinct,” Wells said.
“Here’s what the record shows: there were some jellyfish, sponges, and worms prior to the Cambrian, although there’s no evidence to support Darwin’s theory of a long history of gradual divergence.
“Then at the beginning of the Cambrian—boom!—all of a sudden, we see representatives of the arthropods, modern representatives of which are insects, crabs, and the like; echinoderms, which include modern starfish and sea urchins; chordates, which include modern vertebrates; and so forth. Mammals came later, but the chordates—the major group to which they belong—were right there at the beginning of the Cambrian.
“This is absolutely contrary to Darwin’s Tree of Life. These animals, which are so fundamentally different in their body plans, appear fully developed, all of a sudden, in what paleontologists have called the single most spectacular phenomenon of the fossil record.”
Spectacular, indeed. It was staggering! But I was having trouble thinking in vast geological terms, where words like “sudden” and “abrupt” have meanings quite different from how we might use them in everyday conversation. I needed more clarity.
“How suddenly did these animals come onto the scene?” I asked Wells. “Put it into context for me.”
“Okay,” he said. His eyes swept the room, looking for a suitable illustration. Finding none, he turned to me and asked: “Are you a football fan?”
I felt trapped. I didn’t want to admit that I’ve followed the hapless Chicago Bears ever since I was a teenager. 24 After all, my credibility was at stake! So I kept my answer vague: “Uh, yeah, I like the game.”
“Okay,” he said, “imagine yourself on one