I Was Wrong About Homo naledi

A reconstruction of Homo naledi's skull (click for credit)
A reconstruction of Homo naledi’s skull (click for credit)
Last September, the media was abuzz about a group of fossils which was supposed to represent a new species: Homo naledi. The fossils were special in many respects, but there were two that stood out: First, the fossils had characteristics that indicated they might be related to modern humans. Second, they looked like they were the result of deliberate burial, which indicates distinctly human behavior.

After reading the scientific papers that had been published regarding the fossil, I wrote a blog post about it. I was very skeptical of the authors’ interpretation that the fossils represented some species of ancient human. To my untrained eye, the fossils seemed to be characteristic of extinct apes, like those found in the genus Australopithecus. In addition, it was hard for me to believe that the collection of fossils even belonged to a single species. There seemed to be too many variations among the fossils, especially when it came to the skulls. Of course, I was quick to point out:

Now please understand that I am not a paleontologist. I am not even a biologist. I am simply a nuclear chemist who has taken an interest in the creation/evolution controversy. As a result, you need to take my comments for what they are worth.

I have been following the scientific papers that have been published since September, and I think I can unequivocally say that my comments weren’t worth very much. Because of several different analyses (both in the secular and creationist literature), I have changed my mind. Once again, who knows how much this conclusion is worth, but I now think that the balance of the scientific evidence indicates that Homo naledi is a single species, and it is probably human.

What accounts for this about-face? There are several factors. A detailed analysis of the foot indicates it is very human-like, and a similarly detailed study of the hand shows that while the fingers are more curved than one would expect, the other characteristics line up with what you find in a human hand. In addition, a preliminary reconstruction of the way it walked indicates a fairly standard human gait.

However, the most important factor in changing my mind was a recently-published special issue of The Journal of Creation Theology and Science. Since it is an open-access journal, I would encourage anyone who is interested in a thoroughly scientific evaluation of Homo naledi from a creationist perspective to read it.

In this special issue, Dr. Todd Wood does a baraminology analysis using an extensive set of fossil characteristics. He shows that Homo naledi groups together with humans, while other clearly non-human fossils do not. In addition, Jean O’Micks does a separate baraminology analysis that comes to the same conclusion. Finally, Dr. Kurt Wise evaluates the fossils from a paleontological perspective, confirming that they are all probably from the same species and that they are probably the result of some kind of burial ritual.

I personally think that Dr. Wise has the best overall summary of what Homo naledi means:

The presence or absence of brow ridges, thin or thick skull bones, flexed or rounded occipital bones, more horizontal or vertical orientation of the hip, straight or curved toes or fingers, large or small body size, large or small teeth, gracile or robust mandible, and a host of other characters probably have little or no impact on a human’s survivability. They certainly do not define a human being. It would even seem that brain size has little importance in that regard – at least as long as it is at least as large as the brain of H. floresiensis, well less than half the brain size of modern human populations. At the very least, as Berger et al. conclude, we need to cease defining humanity on the basis of individual morphological features. In fact, if we are to have ANY possibility of success in defining the humanity of fossils based upon morphological characters (and even that is questionable), it will be by means of holistic data sets and the kind of multivariate methods used in quantitative baraminology.

In other words, there is just too much diversity among human beings to use individual fossil characteristics to come to an evaluation of humanity. As a result, we have to start using more detailed methods, such as baraminology, to evaluate potentially human fossils. That was my mistake in looking at the original Homo naledi papers. I was focusing on individual fossil characteristics.

So based on what we know right now, I think Homo naledi represents a specialized, post-Flood human being. Of course, I am willing to change my mind again, if new data or new analyses come to light.

5 thoughts on “I Was Wrong About Homo naledi”

  1. Your comments were interesting until I came across your last paragraph, concluding it was a post-Flood human being. Are you serious? You, a chemist, still believe in the Bible flood? How scientific do you think that is???
    I am not a paleontologist, nor a biologist. I´m a mechanical engineer, with fair knowledge of the laws of physics, thermodynamics, astronomy, etc. By the way, I am skeptic, non-theist.

    1. I am quite serious, Adrien, and I think belief in the Biblical Flood is very scientific. Indeed, I think it offers the best explanation of the scientific data that we currently know. The PhD paleontologist I quote (Dr. Kurt Wise) agrees, as does the PhD biochemist who did the baraminology analysis I discuss. I have my PhD in nuclear chemistry, which means I know quite a bit about physics and thermodynamics as well. I expect to be teaching thermodynamics to engineering students this fall at Anderson University.

    2. Adrien,
      From an M.E. perspective, what are your biggest hang ups about the possibility of a global flood? I see you mentioned you are a skeptic, which is good, to an extent. Is there anything in the traditional understanding of the age of the earth that you are equally skeptical about?

  2. I’m curious how much genetic differentiation plays into these oddly shaped humans. From a YE perspective, there was a significant bottleneck in the gene pool post-flood which limited the amount of genetic material that was available. I wonder how much more robust variation might have been available to the humans that lived pre-flood which may account for the multitude of different shaped fossils, making it hard to reconcile to our modern skeletal shape. Just a thought.

    1. That’s a good point, Tim. However, this particular fossil is almost certainly post-Flood, given the way it was preserved. One other consideration would be that we know there are such things as adaptive mutations – mutations that occur specifically to help organisms adapt to changing environments. My recent post about citrate-using bacteria discusses this. Creationists tend to think that there are specific mechanisms built into the genome to produce adaptive mutation, such as Dr. Borger’s suggestion of variation-inducing genetic elements. As a result, genetic diversity could have sprung up post-Flood as well.

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