Lucy

In my reading today of Jerry Coyne’s Why Evolution Is True, I learned more about “Lucy”, or Australopithecus afarensis. According to many evolutionists, Lucy resembled both apes and humans, making her a transition between the two (or at least showing that such a transition is possible).

“Lucy” was found in Ethiopia in 1974 by Donald Johanson and Tom Gray, and she dates back 3.2 million years.

According to Coyne, Lucy walked on two legs, meaning she was not a “knuckle-walking ape”. Coyne states on page 200:

How can we tell [that Lucy walked on two legs]? From the way that the femur (thighbone) connects to the pelvis at one end and to the knee at its other…In a bidepally walking primate like ourselves, the femurs angle in toward each other from the hips so that the center of gravity stays in one place while walking, allowing an efficient fore-and-aft bipedal stride. In knuckle-walking apes, the femurs are slightly splayed out, making them bowlegged. When they try to walk upright, they waddle awkwardly, like Charlie Chaplin’s little tramp…If the femur angles toward the middle, it’s bipedal. And Lucy’s angle in—at almost the same angle as that of modern humans. She walked upright.

On page 202, Coyne delineates how Lucy resembles both humans and apes:

Like other australopithecines, Lucy had a very apelike head with a chimp-sized braincase. But her skull shows more humanlike traces too, such as a semiparabolic tooth row and reduced canine teeth…Between the head and pelvis she had a mixture of apelike and humanlike traits: the arms were relatively longer than those of modern humans, but shorter than those of chimps, and the finger bones were somewhat curved, like those of apes. This has led to the suggestion that afarensis might have spent at least some time in the trees. One could not ask for a better transitional form between humans and ancient apes than Lucy. From the neck up, she’s apelike; in the middle, she’s a mixture; and from the waist down, she’s almost a modern human.

Coyne also mentions the “Laetoli footprints” found in Tanzania in 1976, which have been attributed to Lucy. Coynes states on pages 201-202:

After careful excavation, the footprints turned out to be an eighty-foot trail made by two hominins who had clearly been walking on two legs (there were no impressions of knuckles)…And the feet were almost certainly from Lucy’s kin: the tracks are the right size, and the trail dates from around 3.6 million years ago, a time when A. afarensis was the only hominin of record.

Again, Coyne denies that Lucy was a “knuckle-walking ape”.

What do creationists do with Lucy?

According to this article from Creation (author?), we don’t have enough of Lucy to tell what she is:

According to Richard Leakey, who along with Johanson is probably the best-known fossil-anthropologist in the world, Lucy’s skull is so incomplete that most of it is ‘imagination made of plaster of paris’. Leakey even said in 1983 that no firm conclusion could be drawn about what species Lucy belonged to.

You can see what parts we have of Lucy in this wikipedia article, and make your own judgment about whether or not one can extrapolate a complete picture from those pieces of the puzzle. I’m not sure how we can tell the length of Lucy’s arms, but we do see key pieces that Coyne mentions, such as the femur, the pelvis, and the jaw.

In this article by Michael Oard (a meteorologist), we encounter the argument that Lucy was a knuckle-walker. Oard quotes the scientists B.G. Richmond and D.S. Strait:

Regardless of the status of Lucy’s knee joint, new evidence has come forth that Lucy has the morphology of a knuckle-walker, which is a distinctly quadrupedal specialization characteristic of some living apes and is quite different than walking upright. Richmond and Strait identify four skeletal features of the distal radius of the living knuckle-walking apes, chimpanzees and gorillas. They also identify similar morphological features on two early ‘hominids’, including Lucy: ‘A UPGMA clustering diagram … illustrates the similarity between the radii of A. anamensis and A. afarensis and those of the knuckle-walking African apes, indicating that these hominids retain the derived wrist morphology of knuckle-walkers.’

In an interview, Richmond stated that after they analyzed the wrist characteristics of living knuckle-walkers, he and Strait walked across the hall to check plaster casts at the National Museum of Natural History: ‘I walked over to the cabinet, pulled out Lucy, and—shazam!—she had the morphology that was classic for knuckle walkers .’

Oard’s point is that Lucy’s radius and wrist resemble those of knuckle-walking apes. The authors Oard quotes, however, say that Lucy merely ratained “knuckle-walking” features from an ancestor, without actually using them. While Oard acknowledges that Lucy differs from knuckle-walkers in certain respects, he goes on to say that such is also the case with “living knuckle-walkers”: there are knuckle-walkers today that lack some characteristics of most knuckle-walkers (this echoes the weird fish argument). Oard’s conclusion is that ”Maybe there is no evolutionary relationship at all, and these are all unique, extinct apes?”

On that note, William Hoesch states in this article that Lucy only walked upright part-of-the-time:

And so you ask, what makes Lucy such a great missing link? Angles of bones in the (reconstructed) hip joint and knee joint suggest that Lucy spent part of her time walking upright. That is as strong as the evidence gets that she was related to humans. Virtually no anatomists will support Johanson’s claim that Lucy was a habitual upright walker, yet this is what most textbooks boast.

Hoesch doesn’t give details as to why Lucy couldn’t have been a “habitual upright walker”.

What about the Laetoli footprints? Hoesch states the following:

There is one more piece of evidence that has been used to argue that Lucy was an upright walker: the Laotoli footprints. In strata comparable in age to those from which Lucy came are a set of very well defined fossil footprints. Remarkably, anatomists are unanimously agreed that the footprints are indistinguishable from those made by modern man on a beach. Rather than admit this as evidence that man and Lucy lived side-by-side in the past, it is claimed that an ape like Lucy must have made the footprints because “we all know” that man hadn’t evolved yet. This, despite the fact that it is almost inconceivable that an austro-lopithocine foot could have done it!

Hoesch says that an austrolopithocine foot couldn’t have made those footprints, whereas Coyne affirms that the tracks are the “right size” for Lucy. Moreover, Coyne says that those are Lucy’s tracks because they date close to the time of Lucy (more than three million years ago), a time when we don’t see traces of homo-sapiens. What Hoesch does with that, I do not know. I’m unaware of his position on radiocarbon dating.

Finally (for this post), there is this article by David Menton, who refers to three Israeli scientists who argue that Lucy was not our ancestor. Menton states that “Au. afarensis has a lower jaw bone (mandible) that closely resembles that of a gorilla—not that of a human or even a chimp.” Menton then goes into technicalities about Lucy’s jaw, and how it resembles that of a gorilla. It’s amazing how Coyne can see human features in Lucy’s teeth, whereas Menton believes that there are gorilla features in Lucy’s jaw.

I’ll stop here. I’m unqualified to say what Lucy was!