Crooked Dealer at Sima de los Huesos

A fossil from Sima de los Huesos.

While other groups of young-Earth creationists may hold differing opinions, the Institute for Creation Research insists that Neanderthals were humans too. This is all very well, but for reasons that are not at all clear they take this position to the extreme, minimising, misreporting, or denying any genetic and morphological evidence of differences between modern humans and their former contemporaries, and trampling over the more nuanced scientific view that Neanderthals were very closely related to us yet also a distinct group. Today Brian Thomas writes “Human Remains in Spain: Neandertal or Not?“, going so far that he ties himself up in knots.

A paper in Science – “Neandertal roots: Cranial and chronological evidence from Sima de los Huesos” (pdf), published on the 20th of June – investigated the accretion model of Neanderthal origins. The cliffs notes on this idea seems to be that the notable Neanderthal-specific features appeared at different times in a stepwise fashion, with those associated with the jaw for example developing before those related to the brain. The skeletons at the Sima de los Huesos cave in Spain, being around 430,000 years old according to this paper, lie in the middle of this transition and so provide a test case (who said you couldn’t test things in “historical science”?). The authors looked at the bones of 17 individuals and did indeed find Neanderthal faces with more archaic brains. They write:

Lumping at Dmanisi

Palaeontologists at Dmanisi, an increasingly famous village in Georgia, have made some quite interesting discoveries: a small collection of early Homo skeletons from people living in the same place at the same time that are nevertheless fairly variable in appearance, as exemplified by the recently-described “skull 5.” The usual rules of population dynamics say that you can’t have different species that have the same niche (i.e. they have same shtick – they live in the same way, eat the same food etc) living in the same place – one of them will quickly win out and exclude the others. If this hasn’t happened – and it doesn’t seem to have at Dmanisi – we must conclude that the organisms are or were of the same species.

A Strange New Paternal Lineage

[Update: Waking up this morning I find that the ICR article this was based on has vanished (it may still return at a later date). I have a zotero capture if anyone wants a full copy of it.] [Update #2: It is indeed back now, and I’ve added a TL;DR summary at the bottom.]

In mammals (including humans) most DNA gets mixed together as it gets passed on from generation to generation: chromosomes come in pairs, one from the mother and the other from the father; but when sperm and eggs are produced these chromosomes swap segments, and the chromosome that ends up in a given sperm or egg is entirely random. There are two exceptions to this rule. Mitochondrial DNA (mtDNA) can only be inherited from the mother – though both sexes have it – while the “Y chromosome” is only passed down from father to son.

This property makes these two varieties of DNA extremely useful in tracing ancestry, as distinct lineages can be found and compared. When these lineages are traced backwards they can only merge, never split, and thus will eventually converge to a point. The human mitochondrial genome has famously been traced back to “Mitochondrial Eve,” who lived between somewhere 140 and 240 thousand years ago, probably in Africa. “Y-chromosomal Adam” (which doesn’t roll off the tongue quite as well) meanwhile is only dated to around 60 to 140 thousand years before the present, but lived on the same continent.

Omnivorous Neanderthals

The most recent missed Brian Thomas article was called Neandertals Apparently Knew Medicinal Plants. The primary subject was a Naturwissenschaften paper from August called Neanderthal medics? Evidence for food, cooking, and medicinal plants entrapped in dental calculus (available open-access, at least for the rest of the month), which examined hardened dental plaque (calculus) from Sidrón Cave Neanderthals and the microfossils and molecules embedded within it:

Our results provide the first molecular evidence for inhalation of wood-fire smoke and bitumen or oil shale and ingestion of a range of cooked plant foods. We also offer the first evidence for the use of medicinal plants by a Neanderthal individual.

The first conclusion that Thomas draws is the same as Jeff Tomkins did a couple of weeks ago, namely that Neanderthals were human. As such, the same response can be made as then: while it’s true that any reasonable definition of ‘human’ not arbitrarily restricted to what we currently call Homo sapiens would need to include Neanderthals, and even that a case can be made for the idea that the distinction between H. sapiens and Neanderthals in fact lies at the subspecies level, there are still differences (primarily morphological) between the two groups. The creationist narrative being pushed is that Neanderthals are just another group descended from Adam, and their claims that they were “fully human” and “identical” to modern humans – both true if you use certain definitions both of ‘human’ and ‘identical’ – are not so much contrary to the current scientific view as an attempt to undermine it. The appeal of saying ‘we’re right, the scientists were wrong’ to the creationists, no matter how accurate that really is, cannot be understated.

Neanderthals Were Human

As everyone should know by now, all modern humans descended from populations that left Africa are also partially descended from our late cousins, the Neanderthals. A paper published a couple of weeks ago in PLoS One comes to the unsurprising conclusion that North Africans also have the same mixed ancestry. Today we have an article called Neandertal DNA Research Confirms Full Human Status. It’s by Jeff Tomkins, who when he last commented on this subject screwed up quite impressively – this time around we have a slight improvement, at least.

The question of where Neanderthals should be classified is a legitimate issue. They are traditionally considered to be their own, separate species – Homo neanderthalensis, where we are of course Homo sapiens. But an alternative method is to give Neanderthals a subspecies level status, as Homo sapiens neanderthalensis. While I’m a long way from being any kind of expert, this is a form that I’m quite fond of. However that being said that classification makes us Homo sapiens sapiens, and even one “wise” is frankly one too many.

There are a number of things going for the subspecies idea. Certain stricter definition of the very concept of a “species” have it that if two populations can at all viably interbreed, as we have evidence for here, then they must be the same species. There is also increasing evidence that Neanderthals weren’t the dumb brutes everyone imagines they were – they were arguably at least our equals in many of those things we think we are so great at, if not necessarily the same species as us. Even if we don’t want to extend our self-congratulatory species label to the Neanderthals it makes sense to call them, and likely many other Homo species, “human.” If we one-day found a “lost tribe” of Neanderthals (we wont) we would, from at least a moral and ethical standpoint, have to call them such.

Some Common Misconceptions: Cavemen and Comment Threads

I have another Your Origins Matter post to share with you. This one is called Meet Your ‘Not So’ Ancient Relatives, and is about “cavemen.”

For decades, at least since Darwin’s time, cavemen have been given little respect.  They have been portrayed as knuckle-dragging near-apes that conked their women on the head with a club and dragged them into their caves by the hair.  Not until The Flintstones did cavemen find a semblance of dignity.  Fred would go to work daily peddling his rock-mobile, while Wilma kept the home all dressed up in her finest pearls.  More recently, cavemen have been given a greater opportunity to show their more “human” side in TV commercials for a leading auto insurance company.  Here, at least, we get the feeling that cavemen really are human after all.

The opening line here (bolded in the original) is impressive. It manages to implicitly blame the negative stereotype of cavemen on Darwin, as if they had previously been considered to be some kind of “knobbly savage” prior to that. To the contrary, wikipedia is of the opinion that the basis of the stereotype dates back to the middle ages. Discounting that poorly-sourced article and concentrating on the actual bones, both Neanderthals and Cro-Magnons – the latter group is entirely ignored by YOM – were only discovered around “Darwin’s time.” It’s difficult to blame him, but doing it implicitly like they did is easy.

The Denisova …Human?

The Denisova hominins were a group of humans that, similar to the more famous Neanderthals, survived until just a few tens of thousands of years ago. Their discovery was announced only in 2010, in the form of a portion of a child’s little finger extracted from the Denisova cave in Siberia. Since then it has been determined that a tooth found in 2000 was from the same group. Curiously, given the finds location in Russia, the Denisovans are believed to have interbred with the ancestors of people that now live in the vicinity of Melanesia.

We can tell all this from such scant evidence because conditions in the cave allowed the aforementioned finger bone to preserve the complete genome of its owner. Most recently this has been sequenced with as much fidelity as you would get from an analysis of a living person. Brian Thomas writes: Is Fossil Finger Genome Human?

The Denisovans are similar enough to modern humans that creationists must include them on our side of their rather arbitrary human-ape division. They have inherited the “fully human” epithet of the Neanderthals. For example:

Pre-emptive Strike: Neanderthal Double-Think

Doing the science blogosphere rounds is a paper in PNAS – Effect of ancient population structure on the degree of polymorphism shared between modern human populations and ancient hominins, pdf available here – that claims that the observed differences in genetic similarity with Neanderthals between Eurasians and Africans can be explained entirely by the population structure of ancient Africa and without recourse to interbreeding between Neanderthals and humans leaving the continent. This has received a fair bit of flack from said blogs – first because the media were allowed to publish articles on the paper some time before it was actually released, but later on the grounds that the paper was “obsolete.”

Homo (sapiens?) neanderthalensis

Some weeks back it was announced – in the words of Jennifer Viegas of Discovery News, to take an example at random – that “All Non-Africans Part Neanderthal, Genetics Confirm.” The “confirms” part referring to the ongoing discussion about whether or not humans and Neanderthals bred with each other. Before now it was merely “thought,” now it is “confirmed.”

Naturally, this being evolutionary related, the Institute for Creation Research wants to get it’s opinion on the matter out there. The YEC point of view on Neanderthals is that they didn’t just breed with humans, they were humans, same as any other. And so, Brian Thomas has written a piece entitled More Evidence Neandertals Were Human. There is some confusion over the spelling used – I use an ‘h’ for Neanderthals, agreeing with Firefox’s spellchecker, Brian Thomas obviously does not, giving Neandertal.