Laetoli

The Laetoli SiteLaetoli, an archaeological site in Tanzania, contains (among other things) a number of hominid footprints, dated in the order of 3.5 to 3.7 million years old. There is a degree on controversy over what made the tracks. Some sources would have you believe that the hominid that made the tracks would have to have been quite “modern” in the way that they walked. Others would disagree.

In late July a paper came out that more-or-less seems to confirm that the tracks are indeed by animals with a more modern gait, but cannot answer the question of what species made it.

The creationists are naturally all over this, on the grounds that, because the first human ancestors that are considered to have been able to make the tracks evolved a few million years after these tracks were formed, evolution is All Wrong. As Brian Thomas puts it in his headline, Laetoli Footprints Out of Step with Evolution. Harr harr, I sees what you did there. It’s not particularly funny.

Let’s see what he has to say for himself:

Repeated examinations of the biomechanics required to make this famous set of tracks have consistently shown that they must have been made by something almost exactly identical to modern human feet. An exhaustive study published in 1990, for example, found the “footprint trails at Laetoli site G resemble those of habitually unshod modern humans.”2 And a 2010 analysis similarly showed that the Laetoli track maker (or makers) “walked with weight transfer most similar to the economical extended limb bipedalism of humans.”3

I would dispute the claim that all the examinations have been consistent with each other. Talk.Origins on this subject – in a page that has not been updated for this new study – points out that always conveniently forget to mention other studies that showed the opposite. It should be pointed out that the ‘2010 analysis’ mentions that there is significant evolutionary advantage to walking the way that humans walk, rather than the way that apes do. There is no reason why hominids from that far back couldn’t walk like this, except that we don’t really see that clearly in the fossil record.

If the tracks look like they were made by man, and if study after study repeatedly concludes that the tracks are indistinguishable from those of a human, then why are researchers still questioning their origin? The only reason is that these tracks are out of step with the evolutionary story.

Woah there! I’ve already covered the ‘repeatedly,’ but indistinguishable? Let’s take a look at the study itself before we jump so far, shall we? Here’s the abstract in full: (with bold from me)

It is commonly held that the major functional features of the human foot (e.g. a functional longitudinal medial arch, lateral to medial force transfer and hallucal (big-toe) push-off) appear only in the last 2 Myr, but functional interpretations of footbones and footprints of early human ancestors (hominins) prior to 2 million years ago (Mya) remain contradictory. Pixel-wise topographical statistical analysis of Laetoli footprint morphology, compared with results from experimental studies of footprint formation; foot-pressure measurements in bipedalism of humans and non-human great apes; and computer simulation techniques, indicate that most of these functional features were already present, albeit less strongly expressed than in ourselves, in the maker of the Laetoli G-1 footprint trail, 3.66 Mya. This finding provides strong support to those previous studies which have interpreted the G-1 prints as generally modern in aspect.

That is to say, they are not ‘indistinguishable.’ See also the following picture from the 2010 study:

Human vs Laetoli footprint

Note the differences between the top and bottom foot (especially scale). Mr Thomas continues regardless:

If humans made these tracks, then all the textbooks will have to be re-written to say that humans evolved a million and a half years earlier in evolutionary “time.” How embarrassing that would be, especially because these older layers contain fossils of the candidate ape forms from which modern man supposedly evolved. Many evolutionists will not consider that the Laetoli tracks were left by a fully developed Homo sapiens, since that would mean that modern man descended from an ape-like creature that existed after modern man was already alive and walking!

Disregarding Mr Thomas’ silly straw man who I’m pretty sure I already incapacitated a moment ago (look, he’s floating so serenely down the river), what makes him think that it would be embarrassing to announce (with, of course, much better evidence) that “modern” bipedalism evolved much early than “[i]t is commonly held”? You’d be famous! Science has no problem with admitting that it’s wrong – it’s creationists who have that problem. In any case, they aren’t particularly ‘wrong’ here either. Mr Thomas, as I have established, is wrong (about the ‘indistinguishable,’ which is the core of his thesis). I doubt he will admit it.

You get the picture. While the topic is indeed interesting, Brian Thomas’ article leaves me with a distinct feeling of ‘so what?’

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2 thoughts on “Laetoli

  1. Pingback: A. sediba, and The Star That Should Not Exist « Eye on the ICR

  2. Pingback: A. sediba and the Laetoli Footprints « Eye on the ICR

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