Editor's Note: This article appeared in a Supplemental Issue of Salvo Magazine on Science and Faith. For more information about the special issue, visit here: SALVO 26 Science & Faith Supplement Fall 2013.
The meeting room was tense as Ronald Wetherington, a professor of anthropology at Southern Methodist University, took the podium. He was about to address the Texas State Board of Education before its vote in March 2009 over whether to inform students about scientific weaknesses in neo-Darwinian evolution.
And what Dr. Wetherington told the board is that there are no weaknesses. Human beings have "arguably the most complete sequence of fossil succession of any mammal in the world," he said. "No gaps. No lack of transitional fossils. . . . So when people talk about the lack of transitional fossils or gaps in the fossil record, it absolutely is not true." According to Wetherington, the field of human origins provides "a nice clean example of what Darwin thought was a gradualistic evolutionary change."
It is not uncommon for evolutionary scientists like Wetherington (even those who teach at Christian universities) to be adamant about the evidence in favor of human evolution. Digging into the technical literature, however, we find a situation that's starkly different from the one presented by Wetherington and many other evolutionary scientists who engage in public debates.
A closer look at the literature shows that hominin fossils generally fall into one of two categories—ape-like species or human-like species (of the genus Homo) —and that there is a large, unbridged gap between them. Despite the claims of many evolutionary paleoanthropologists, the fragmented hominin fossil record does not document the evolution of humans from ape-like precursors. In fact, scientists are quite sharply divided over who or what our human ancestors even were. Newly discovered fossils are often initially presented to the public with great enthusiasm and fanfare, but once cooler heads prevail, their status as human evolutionary ancestors is invariably called into question.
Early Human History
The details of the earliest stages of human origins are murky. They come from what UC–Berkeley paleoanthropologist Tim White once called "a black hole in the fossil record."1 There are, to be sure, three main species that have emerged as contenders for the supposed common ancestor of humans and apes. But despite what is printed in the media, the extant fossils for all three species are fragmented and greatly disputed by experts.
When Orrorin tugensis was initially discovered in 2001, the New York Times ran a story titled "Fossils May Be Earliest Human Link."2 The fossil itself—dubbed Millennium Man—was known only from "an assortment of bone fragments,"3 including pieces of the arm, thigh, and lower jaw, as well as some teeth. Debate over Orrorin has centered on whether it was an early hominin capable of walking upright, and on this point a 2007 commentary made a key admission: "All in all, there is currently precious little evidence bearing on how Orrorin moved."4
When Sahelanthropus tchadensis was first discovered in 2002, the popular science journal New Scientist claimed that "the new species is close to the common ancestor of humans and chimpanzees."5 But since that fossil was known only from a skull and some jaw fragments, experts naturally disagreed. For example, Brigitte Senut, a leading researcher at the Natural History Museum in Paris, said, "I tend towards thinking this is the skull of a female gorilla."6 Three paleoanthropologists subsequently concluded in an article in Nature that "Sahelanthropus was an ape."7
The most recent hyped-up hominin fossil find was Ardipithicus ramidus, dubbed "Ardi" by its promoters in the media. The Discovery Channel ran the headline "'Ardi,' Oldest Human Ancestor, Unveiled" and quoted Tim White as stating that Ardi was "as close as we have ever come to finding the last common ancestor of chimpanzees and humans."8 Doubts arose, however, after news reports acknowledged that "some portions of Ardi's skeleton were found crushed nearly to smithereens and needed extensive digital reconstruction," and that its pelvis initially "looked like an Irish stew."9 Later, technical papers in both Science and Nature disavowed claims that Ardi was a human ancestor.10 According to Time magazine, one of the authors of those papers, Esteban Sarmiento, "regards the hype around Ardi to have been overblown."11
Australopithecines Are Like Apes
While early hominin fossils are controversial, due to their fragmented condition, there is one major group—the australopithecines—that is widely promoted as directly ancestral to humans. The primary claim is that australopithecines had the head of a chimpanzee but a body that allowed it to walk upright, like humans.
Despite the prevalence of that standard view, authorities have found that the fingers, arms, chest, hand bones, striding gait, shoulders, abdomen, inner-ear canals, developmental patterns, toes, and teeth of australopithecines point away from their being human ancestors and/or suggest that they didn't have human-like bipedal locomotion.12 For example, an article in Nature observed that the most complete australopithecine specimen—the famous fossil Lucy—was "quite ape-like," especially with respect to her "relatively long and curved fingers, relatively long arms, and funnel-shaped chest."13 The article reported that Lucy's hand bones suggest that she "'knuckle-walked', as chimps and gorillas do today."14
Paleoanthropologist Leslie Aiello, who served as head of the anthropology department at University College London, stated that when it comes to locomotion, "Australopithecines are like apes, and the Homo group are like humans. Something major occurred when Homo evolved, and it wasn't just in the brain."15
A Big Bang Origin of Homo
When the human-like members of our genus Homo appear, they do so abruptly. A paper in the Journal of Molecular Biology and Evolution called the appearance of Homo sapiens "a genetic revolution" in which "no australopithecine species is obviously transitional."16 In a 2004 book, the famed evolutionary biologist Ernst Mayr explained that "the earliest fossils of Homo, Homo rudolfensis and Homo erectus are separated from Australopithecus by a large, unbridged gap" without "any fossils that can serve as missing links."17
The lack of fossil evidence for this hypothesized evolutionary transition was confirmed by three Harvard paleoanthropologists, who wrote:
Of the various transitions that occurred during human evolution, the transition from Australopithecus to Homo was undoubtedly one of the most critical in its magnitude and consequences. As with many key evolutionary events, there is both good and bad news. First, the bad news is that many details of this transition are obscure because of the paucity of the fossil and archaeological records.18
And the good news? "Although we lack many details about exactly how, when, and where the transition occurred from Australopithecus to Homo," the three went on, "we have sufficient data from before and after the transition to make some inferences about the overall nature of key changes that did occur."19
In other words, the fossil record provides us with ape-like australopithecines ("before") and human-like Homo ("after"), but not with fossils documenting a transition between them. In the absence of intermediaries, we're left with "inferences" of a transition based strictly upon the assumption of Darwinian evolution. No wonder one commentator argued that if we take the fossil evidence at face value, it implies a "big bang theory" of the appearance of our genus Homo.20
Resistance Isn't Futile
Despite the constant drumbeat of media stories announcing the discovery of the latest "missing link," the evidence shows that human-like forms appear abruptly in the fossil record, without any fossils connecting us to our alleged ape-like evolutionary ancestors. This contradicts the expectations of neo-Darwinian evolution and suggests that unguided evolutionary mechanisms do not account for the origin of our species. •
[1.] Tim White, quoted in Ann Gibbons, "In Search of the First Hominids," Science (Feb. 15, 2002), 295:1214–1219.
[2.] John Noble Wilford, "Fossils May Be Earliest Human Link," New York Times (July 12, 2001).
[3.] Rick Potts and Chris Sloan, What Does It Mean to Be Human? (National Geographic, 2010), p. 38.
[4.] Esteban E. Sarmiento, Gary J. Sawyer, and Richard Milner, The Last Human: A Guide to Twenty-Two Species of Extinct Humans (Yale Univ. Press, 2007), p. 35.
[5.] Jeff Hecht, "Oldest hominid skull shakes human family tree," New Scientist (July 10, 2002).
[6.] "Skull find sparks controversy," BBC News (July 12, 2002).
[7.] Milford H. Wolpoff et al., "Sahelanthropus or 'Sahelpithecus'?" Nature (Oct. 10, 2002), 419:581– 582.
[8.] Jennifer Viegas, "'Ardi,' Oldest Human Ancestor, Unveiled," Discovery News (Oct. 1, 2009).
[9.] Michael D. Lemonick and Andrea Dorfman, "Ardi Is a New Piece for the Evolution Puzzle," Time (Oct. 1, 2009).
[10.] Esteban E. Sarmiento, "Comment on the Paleobiology and Classification of Ardipithecus ramidus," Science (May 28, 2010), 328:1105b; Bernard Wood and Terry Harrison, "The evolutionary context of the first hominins," Nature (Feb. 17, 2011), 470:347–352.
[11.] Eben Harrell, "Ardi: The Human Ancestor Who Wasn't?" Time (May 27, 2010).
[12.] For a more detailed discussion of the fossil evidence and human origins, see Casey Luskin, "Human Origins and the Fossil Record" in Science and Human Origins (Discovery Institute Press, 2012), pp. 45–83.
[13.] Mark Collard and Leslie C. Aiello, "From forelimbs to two legs," Nature (March 23, 2000), 404:339–340.
[15.] Leslie Aiello, quoted in Richard Leakey and Roger Lewin, Origins Reconsidered: In Search of What Makes Us Human (Anchor Books, 1993), p. 196.
[16.] John Hawks et al., "Population Bottlenecks and Pleistocene Human Evolution," Journal of Molecular Biology and Evolution (2000), 17(1):2–22.
[17.] Ernst Mayr, What Makes Biology Unique? (Cambridge Univ. Press, 2004), p. 198.
[18.] Daniel Lieberman, David Pilbeam, and Richard Wrangham, "The Transition from Australopithecus to Homo," in Transitions in Prehistory: Essays in Honor of Ofer Bar-Yosef (Oxbow Books, 2009), p. 1 (internal citations removed).
[20.] "New study suggests big bang theory of human evolution," (Jan. 10, 2000) at http://www.umich.edu/~newsinfo/Releases/2000/Jan00/r011000b.html.