Todd Wood's Take on Danuvius

Todd Wood is always interesting to read, even if I don't share his chronological leanings.  He has thoughts on the new Miocene ape from Bavaria, Danuvius:

Based on the fragmentary remains, we make some really interesting observations about the anatomy of Danuvius. These apes had strongly opposed big toes, which would allow them to effectively grip things with their feet. Their tibiae (shinbones) have the kinds of joints that would allow them to walk upright, and their femora (thighbones) support that conclusion. These apes might have been in some way bipedal. The arm bones they found have traits that are associated with suspensory locomotion, like hanging from tree branches. The body size was fairly small, about the mass of a bonobo.

As I mentioned in my post, I think the evidence for bipedalism is vastly over-stated and, even if it can be shown that this “Extended Limb Clambering” is shared by other fossil ape finds from the region, there is no particular reason to think that these critters were ancestral to later hominins. It is entirely likely that they exhibited a separate adaptation to this particular style of locomotion.  Todd raises some other questions, though, that are not answered in the paper:

So why not address similarities of Danuvius to later fossil hominins? The authors are trying to establish a new means of locomotion that they call Extended Limb Clambering (ELC). So they compare Danuvius to living primates (where the authors know how they get around), and they're interested in comparing it to contemporary Miocene apes of Europe. But they're not all that excited about other comparisons to later fossil forms like Ardipithecus, Australopithecus, or Orrorin. They also don't relate their findings to later fossil apes in Europe like Graecopithecus or the Trachilos tracks, both of which have been linked to hominins or bipedality. Perhaps they don't think those things are worth talking about (maybe because they're skeptical of Graecopithecus like I am), but I guess I just don't agree.

I think that part of the reason that these questions are not raised is because there is so much of a gap between these finds, chronologically and geographically. There is simply with which to relate them. As Todd points out, the hominin status of Graecopithecus is dubious, at best, and, even if the Trachilos tracks are hominin, they are still quite a distance from Bavaria and six million years later in time.

For now, this fossil ape stands on its own.  If we find other evidence of incipient bipedality in other forms in the area and can relate them to later forms, then the picture might change.  For now, though, Danuvius is a very interesting, odd Miocene ape. 

Upright Ape?

Multiple outlets are reporting on the discovery of a fossil ape that appears to have at least a partially facultatively bipedal stance.  Here is the Fox News version of events:

The remains of an 11 million-year-old ape suggest that our ancestors started to stand upright millions of years earlier, according to scientists.

A team of researchers claims the fossilized partial skeleton of a male ape that lived in the humid forests of what is now southern Germany bears a striking resemblance to modern human bones. In a paper published on Wednesday by the journal Nature, they concluded that the new species — dubbed Danuvius guggenmosi — could walk on two legs but also climb like an ape.

The findings “raise fundamental questions about our previous understanding of the evolution of the great apes and humans,” Madelaine Boehme of the University of Tuebingen, Germany, who led the research, told The Associated Press.

Here is how the Nature paper actually reads:

Here we describe the fossil ape Danuvius guggenmosi (from the Allgäu region of Bavaria) for which complete limb bones are preserved, which provides evidence of a newly identified form of positional behaviour—extended limb clambering. The 11.62-millionyear-old Danuvius is a great ape that is dentally most similar to Dryopithecus and other European late Miocene apes. With a broad thorax, long lumbar spine and extended hips and knees, as in bipeds, and elongated and fully extended forelimbs, as in all apes (hominoids), Danuvius combines the adaptations of bipeds and suspensory apes, and provides a model for the common ancestor of great apes and humans.

First, this is way-the-heck back there, some five and a half million years before the first actual evidence of bipedalism (Orrorin). Second, there are no “hip” remains. The only post-cranial remains are long bones.  Much is inferred.  In hominins, the femoral neck and the connection to the femoral head provide much diagnostic locomotion information.  The fossil remains for this region are very scant, consisting only of a partial head.  Much of the argument for even some bipedality rests with the tibial angle, to wit:

The near perpendicular tibial angle is a shared character between hominins and Danuvius and supports the inference of a habitual valgus knee position and bipedalism for the new genus.

I think a new genus designation is certainly warranted. I have grave reservations about the “bipedalism” designation. We have possible evidence from Crete at 5.5 million years for bipedalism in the form of footprints. That is as far north as it gets.  All of the other evidence we have for the emergence of hominins and bipedalism comes from North Africa.  It is far more likely that this represents an independent adaptation/homoplasy for this hominoid.   If we had more evidence from later in the Miocene or, better yet, the Pliocene, then this might carry more weight.

Did the LCA Have Teeth More Like a Gorilla?

Artificial intelligence is playing a role in understanding human evolution.  From the Australian site News.com comes a story about new work in trying to understand what the last common ancestor to apes and humans might have looked like:

IT’S an image imprinted on our brains: the steady march of evolution from chimp to human. But it’s not quite right.

Monkeys don’t belong on the tree. They have tails.

Chimps, which don’t, are with Bonobos our closest living relatives. And, as such, both should be standing alongside us in the march of life.

Stretching out behind should be a gradually converging branch of earlier variations.

Ultimately, between six and eight million years ago, the branches almost certainly converge on one common ancestor.

We know almost nothing about what that was.

We have reasonably secure evidence of bipedality at around 6 million years in the form of Orrorin tugenensis from Kenya, as well as a crushed skull from Chad called Sahelanthropus that may or may not be 7 million years old, and recently, fossil footprints, purporting to show bipedal walking, from Crete have been uncovered that have been dated to around 5.7 million years ago.  Beyond that, nothing.  That is where the new AI study comes in.

The researchers used machine learning to teach an artificial intelligence to identify and classify fossilised hominid teeth dating from 25 million years ago. It then sifted through these to find patterns of development.

The study published in the science journal PaleoBios found one tantalising tip.

Our common ancestor almost certainly had gorilla-like teeth.

Now, it’s not a lot. And it certainly doesn’t say our ancestor was a gorilla.

But what it does do is add some shape and substance to this nebulous period of our human origins.

The information that is contained in the article is not nearly as cut and dried as is indicated by the news story. From the conclusion:

Given that the divergence of humans and chimpanzees occurred in the late Miocene, and that Miocene apes are much more similar to Gorilla in dental proportions, we assert that gorillas are the more appropriate extant model for the African ape LCA in terms of the relative sizes of the postcanine teeth. This similarity in dental proportions likely has implications for the interpretation of dietary adaptation and possibly phylogenetic relationships in Miocene apes, including the chimpanzee-human last common ancestor.

What this likely means is that, during the Miocene, which was the golden age of the apes, even after the divergence of Gorillas from the main line, there were extant forms that continued to have varying degrees of traits that could be associated with gorillas, presenting a classic case of collateral ancestry.  It is possible that one of the lines eventually led to chimpanzees, while another led to us.  We won't know more until we actually have some fossil remains from that missing time period. 
.

"They Are Digging in the Wrong Place"

Bodie Hodge has a post on the AiG website that is nothing short of astounding.  AiG is, once again, moving the goalposts.  And who is Bodie Hodge?  He is, according to the site: "A speaker, writer, and researcher for Answers in Genesis, Bodie Hodge has a master’s degree in mechanical engineering from Southern Illinois University at Carbondale."  Hodge writes:

Each year there are many headlines, books, technical articles, and videos about another supposed missing link—a supposed link between a land mammal and whale, a dinosaur and bird, an ape and human, and so forth. Usually, these are quite easy to refute by anatomical features.

For example, alleged missing links turn out to be anything but—for example, either ape, human, or a fake (e.g., Piltdown man) or dinosaur, bird, or a fake (e.g., Archaeoraptor).

Nevertheless, these alleged missing links rarely make creationists cringe. I think it frustrates some of the evolutionists because they think they have found some sort of knock-out evidence that they interpret as support for evolution. But creationists rarely bat an eye.

Well, I’m going to let you in on a secret as to why creationists rarely take notice of these alleged missing links. It is because the evolutionists are digging in the wrong place—just like the bad guys in Indiana Jones. When you don’t have the correct information, you can miss the mark significantly.

So evolutionists are just like "the bad guys" in Raiders of the Lost Ark.  Did you catch that?  A casual trip through the fossil record indicates that there are, in fact, many, many transitional forms present.  We now have very detailed sequences from Devonian crossopterygians to early tetrapods, from land mammals to whales, from maniraptoran dinosaurs to birds and, of course, from late Miocene/early Pliocene apes to humans.

But this isn't even the central focus of his post. First, he lists the conventional geological stratigraphy.  He bungles this early on.  He writes: "In a general sense, evolutionists look for alleged dinosaur-to-bird missing links in the Cretaceous and Paleocene (bolded)."  Wrong.  The dinosaur-to-bird sequence dates to the late Jurassic.  Furthermore, the presence of feathers on non-avian dinosaurs suggests that feathers evolved even before the late Jurassic.  By the early Cretaceous, birds were numerous.  The transition had long since ended by the Palaeocene.  Had he done any study of the transition from dinosaurs to birds, he would have known this.

He then writes:

But here is the problem. The rock layers from Cambrian to Miocene—at least mapped in the mountains of Ararat (Genesis 8:4)—were from the Flood.2 Miocene and Eocene rock is intricately part of the makeup of the mountains of Ararat, as is Cretaceous and Triassic (many times inverted, lying above the Miocene and Eocene). Since that time, the upper strata are post-Flood strata—such as Ice Age layers and recent volcanic flows. I understand creationists debate about tertiary sediment (Paleocene through Miocene) and encourage you study this further.

He gives absolutely no justification for this viewpoint. No evidence is presented indicating why pre-Pliocene sediments are flood and Pliocene sediments on up are not.  There is no event to mark this transition, no sedimentary layer that is distinctive.

Nothing. He simply says that it is so, therefore it is. It gets worse:

So when evolutionists say they found a transitional form between an ape and a human in Pliocene rock, creationists hardly flinch. Evolutionists are looking at the rock strata and the age of the earth incorrectly because humans were around long before that rock was ever laid down! Furthermore, humans existed when the Cambrian rock was laid down during the Flood. To go one more step, mankind had dominated the earth for over 1,600 years before the Cambrian rock was laid down!

When someone says that they found a transitional form between a dinosaur and a bird in the Paleocene, again, creationists hardly think twice. Both specimens died the same year in the same Flood and are not related. This is why finding feathers in the rock layers “before the dinosaurs” is not a problem for creationists.4 Nor is it a problem when we find theropod dinosaurs (which supposedly evolved into birds in the evolutionary story) that had eaten birds in lower Cretaceous rock.5

Birds were made on Day Five, which is a day before the dinosaurs; land animals, like dinosaurs, were made on Day Six. Having both buried in Flood sediment isn’t a big deal.

So many questions...

• If humans were around before the rocks were laid down, how is it that we find no humans at the base of the geological/flood column?  In fact, why aren't human remains found throughout the column, if they predate the Cambrian?
• How is it that all of the fossil species that are supposed to be in flood deposits are perfectly sorted, even to the point of brachipods being sorted by crinulation number and trilobites being sorted  by number of compound eye segments?  What about the detailed fossil sequences mentioned above? 
• if humans had ship-building capacity during the time of Noah and existed in towns and settlements, why is there no evidence of this at the bottom of the geological column?
• If humans did, in fact, predate the Cambrian, why do we find a detailed, clear sequence from prehuman hominoids through human precursors to archaic and them modern humans beginning in the Pliocene?  
• If the sediments from the Miocene back to the Precambrian reflect flood deposits, why do we find the largest land mammals, dinosaurs three quarters of the way up the column, when they should have sunk to the bottom?  
• If the sediments from the Miocene back to the Precambrian reflect flood deposits, why do we find features throughout the geological record that could only have happened on the surface, such as rain drops, footprints, hatched dinosaur eggs, cave systems, sand dunes, burned forests, swamps, etc. 

So why aren't any of these things problems for the creationists?

Biblical creationists presuppose the Bible’s truth and subsequently the true history of the earth—including Noah’s Flood. Evolutionists have presuppositions too, albeit, false ones, but presuppositions nonetheless. This is why when evolutionists look at Flood rock they unwittingly believe that the rock was actually laid down slowly and gradually over long ages. I suggest they have been indoctrinated to believe such stories as gradual rock accumulation over millions of years which has never been observed or repeated. Thus, the concept of millions of years is not in the realm of science but interpretation.

The reason that "evolutionists" do this is because every bit of the palaeontological and geological evidence points to a long depositional history with evolutionary diversity.  It is not a matter of indoctrination.  It is a matter of going where the evidence leads.  One might reasonably argue that if you put on young earth creationist blinders, you do not see the vast stretches of time and the changes that the earth has gone through in its long history, but, instead, a flat earth. 

It is common to find nonsense on the AiG site, but this rises to a new level of inanity. This post is terribly written, incorrect, pompous and insulting.  The writer provides no evidence for the position he takes, insults the hard work of scientists who have spent decades piecing together the geological and fossil records, and betrays complete ignorance of basic geology and palaentology.  It is hard to be charitable to Mr. Hodge, who plainly knows nothing of which he writes and, as a result, produces pure drivel. 
 

Five Peculiar Fossils

Colin Barras of The New Scientist has a very short, very peculiar article on five hominin fossils that have been used to define new species and addresses the validity of each in very cursory fashion.  The strength of the article is in the links that it provides.  About Sahelanthropos, he writes this:

Features at the skull’s rear suggest it sat atop a vertical spine like that of a human, hinting that S. tchadensis walked upright. To make sure, other fossils will be needed – particularly from the legs. Unconfirmed reports suggest that a thigh bone was found with the skull, but this has not yet been discussed in a scientific paper. With so little evidence to go on, some are sceptical that S. tchadensis can really yet be defined as a hominin rather than some other form of ape – yet.

These are the least of its problems, as it is likely a surface find. Aside from this, when Wolpoff and colleagues examined the cranial base, here is what they found:

The prominence of the nuchal muscles, so important in head balance and loading, and shoulder movements, is enhanced by the significant development of the tuberculum linearum. The point is not that the TM 266 cranial rear and posterior portion of the cranial base was unlike hominids because the region looks like apes, but that TM 266 had a posture that is not upright because the region reflects nuchal functions similar to those of apes.

The foramen magnum - orbit plane angle does not directly address posture or locomotion in these hominoid primates (contra Zollikofer et al., 2005). Without a key postcranial element such as a pelvis or femur, none of these data provide compelling evidence for upright posture or obligate bipedal locomotion, and the various details of the nuchal plane argue against it. This functional implication has a phylogenetic consequence—by itself it is sufficient to disprove the phylogenetic hypothesis that TM 266 was a hominid.

This isn't skepticism. This is the door slamming shut.  It can be a surface find and still be a Miocene ape. In my recent piece for BioLogos, it did not occur to me to include this fossil since there are so many problems with it.  At this point, in Africa, the earliest reasonable evidence we have for hominins is Orrorin tugenensis. 

Read the whole (short) thing.

5.7 Million Year-Old Human Footprints Found on Greek Island of Crete

Great Googlymoogly!  This one is lighting up all over the Internet.  Fossil footprints have been found in the southern Greek Island of Crete, near the village of Trachilos, that appear to have the distinctive heel-toe-off gait of bipedal humans.  The catch? The prints are 5.7 million years old!  From PhysOrg:

Human feet have a very distinctive shape, different from all other land animals. The combination of a long sole, five short forward-pointing toes without claws, and a hallux ("big toe") that is larger than the other toes, is unique. The feet of our closest relatives, the great apes, look more like a human hand with a thumb-like hallux that sticks out to the side. The Laetoli footprints, thought to have been made by Australopithecus, are quite similar to those of modern humans except that the heel is narrower and the sole lacks a proper arch. By contrast, the 4.4 million year old Ardipithecus ramidus from Ethiopia, the oldest hominin known from reasonably complete fossils, has an ape-like foot. The researchers who described Ardipithecus argued that it is a direct ancestor of later hominins, implying that a human-like foot had not yet evolved at that time.

The new footprints, from Trachilos in western Crete, have an unmistakably human-like form. This is especially true of the toes. The big toe is similar to our own in shape, size and position; it is also associated with a distinct 'ball' on the sole, which is never present in apes. The sole of the foot is proportionately shorter than in the Laetoli prints, but it has the same general form. In short, the shape of the Trachilos prints indicates unambiguously that they belong to an early hominin, somewhat more primitive than the Laetoli trackmaker. They were made on a sandy seashore, possibly a small river delta, whereas the Laetoli tracks were made in volcanic ash.

And now, the other shoe.  How do we know how old the fossil footprints are?  

The coastal rocks at Trachilos, west of Kissamos Harbour in western Crete (Fig. 1a–c), lie within the Platanos Basin, and present a succession of shallow marine late Miocene carbonates and siliciclastics of the Roka Formation, a local development of the Vrysses Group (Freudenthal, 1969 ; van Hinsbergen and Meulenkamp, 2006; Figs. 1d, e and 3a, b). At the top, this marine succession terminates abruptly in the coarse-grained terrigenous sedimentary rocks of the Hellenikon Group (Figs. 1d and 3e, f), which formed by the desiccation of the Mediterranean Basin during the Messinian Salinity Crisis (van Hinsbergen and Meulenkamp, 2006), an event dated to approximately 5.6 Ma (Govers, 2009). The succession (Fig. 1d) contains an emergent horizon with well-preserved terrestrial trace fossils and microbially induced sedimentary structures (Fig. 3d) immediately overlying shallow water ripplemark structures (Fig. 3c).¹

So, the authors are a tad more circumspect than the writers of the PhysOrg story.  The authors posit two hypotheses for their results: 1. the tracks represent the gait of a basal hominin, which explains the non-divergence and shape of the big toe as well as the shape of the ends of the other toes, which resemble those of a human foot and not a non-human foot.  This fits approximately with the dates of the north African remains of Orrorin and, perhaps, that of Sahelanthropus (although that is pretty much a surface find).

The Messinian Crisis was a period of time during the Miocene epoch during which the Mediterranean Sea almost completely dried up.  This crisis began around 6 million years ago and ended around 5.3 million years ago with what is known as the Zanclean flood.  It is estimated that once the barrier at the Strait of Gibraltar was broken, the Mediterranean Sea refilled within two years, which means that the sea level rose at an estimated 30 feet per day.

Okay...now, lets go back here, to the story that came out about four months ago, establishing the possibility that the last common ancestor to apes and humans was in Europe.  In that study, a jaw with human root patterns and an isolated premolar that have both been attributed to Graecopithecus, were re-examined and found by the researchers to have hominin affinities, a surprising conclusion, given their age of 7.15 million years.  At the time that story appeared, I remarked that it was a bit of a stretch to hang one's hat on one premolar and partial ape-like mandible, but in the context of the new finds, maybe not so much.  This strengthens the (admittedly far-fetched) notion that our ancestors did, in fact, originate somewhere in southeast Mediterranean Europe and, over the course of the next two and half million years ago, migrated south to north Africa.

As Per Ahlberg was quoted as saying:

"This discovery challenges the established narrative of early human evolution head-on and is likely to generate a lot of debate. Whether the human origins research community will accept fossil footprints as conclusive evidence of the presence of hominins in the Miocene of Crete remains to be seen."

This is huge news.  Even if we can't place the LCA in southern Europe, we now have bipedalism extending back into the late Miocene. 


¹Gerard D. Gierliński et al, Possible hominin footprints from the late Miocene (c. 5.7 Ma) of Crete?, Proceedings of the Geologists' Association (2017). DOI: 10.1016/j.pgeola.2017.07.006

New 13 Million-Year-Old Miocene Ape Discovery in Kenya

National Geographic (and other outlets) is reporting on a new skull discovered in northern Kenya, near Lake Turkana that is 13 million years old and may reflect the morphology of a sister group to the stem group of hominoids, the group that contains modern apes and humans.  Michael Greshko writes:

“We’ve been looking for ape fossils for years—this is the first time we’re getting a skull that’s complete,” says Isaiah Nengo, the De Anza College anthropologist who led the discovery, supported by a National Geographic Society grant and the Stony Brook University-affiliated Turkana Basin Institute.

Roughly the size of a lemon, the skull belongs to a newly identified species of early ape named Nyanzapithecus alesi. Some of its features resemble those of today’s living Old World monkeys and apes, and the face bears a striking resemblance to today’s infant gibbons.

What’s more, N. alesi offers insight into early apes’ brains, the team reports in their study, published today in Nature. With a volume of about seven tablespoons, N. alesi’s brain cavity was more than double that of other Old World monkeys from the time.

The Miocene is generally thought of as the “Age of the Apes” because there were so many genera (30) and species (over 40) of apes pretty much all over the Old World. As the authors note, however, up to this point, most of the remains have been just jaws and teeth.  This skull is an incredible find and will add immensely to our understanding of this time period. 

New Study: Ardipithecus ramidus Derived In Human Direction

According to Bill Kimbel and colleagues, the skull of Ardipithecus ramidus shows tell-tale signs of being derived in the human direction away from great apes.  From Science Daily:

White's field-research team has been recovering fossil remains of Ardipithecus ramidus in the Middle Awash research area, Ethiopia since the 1990s. The most recent study of the Ardi skull, led by Suwa, was published in Science in 2009, whose work (with the Middle Awash team) first revealed humanlike aspects of its base. Kimbel co-leads the team that recovered the earliest known Australopithecus skulls from the Hadar site, home of the "Lucy" skeleton, in Ethiopia.

"Given the very tiny size of the Ardi skull, the similarity of its cranial base to a human's is astonishing," says Kimbel.

The cranial base is a valuable resource for studying phylogenetic, or natural evolutionary relationships, because its anatomical complexity and association with the brain, posture and chewing system have provided numerous opportunities for adaptive evolution over time. The human cranial base, accordingly, differs profoundly from that of apes and other primates.

In humans, the structures marking the articulation of the spine with the skull are more forwardly located than in apes, where the base is shorter from front to back and the openings on each side for passage of blood vessels and nerves are more widely separated.

Given that the post-cranial remains from Ardipithecus suggest facultative bipedalism, this is not so surprising. If you are going to walk upright at all, you need to be able to see where you are going. This information, in conjunction with the new appraisal of the Orrorin tugenensis remains strongly suggests that, while Orrorin was at or near the junction of the last common ancestor, Ardipithecus, at 1.6 million years later, is quite a bit beyond it. It also reinforces what a terrible model the modern apes are for early human morphology.

Geologically Recent Ape in Europe

Deutsche Welle world has an interesting story about dental remains that have been discovered in Europe that put Miocene apes in the region as recently as 7 million years ago. According to the story:

"The latest data have shown that contrary to the hominids in Western and Central Europe (with the exception of the insular Oreopithecus), hominids from the Eastern Mediterranean may have lived up to 8 to 7.5 [million years ago], preadapted to the more open biotopes of the Balkan-Iranian zoographic province," the team wrote.

What is important to note about this story (and it threw me for a minute) is that the author is using the newer phylogenetic systematics-driven definition of “hominid.” In this scheme, “hominids” are now at the family level and include us and all of the great apes and “hominins” (us and our ancestors) are at the sub-family level.

A problem, voiced by one of the excavators, is, of course, that it is just one tooth, so we cannot say too much about it. Still, it is interesting if it bears up.

----------------
Now playing: Mike Oldfield - Airborn
via FoxyTunes

Casey Luskin and Ardipithecus

Much to my chagrin, I missed this a few weeks back, when Casey Luskin put up an article on the new Ardipithecus remains. Hyperbollically titled Artificially Reconstructed “Ardi” Overturns Prevailing Evolutionary Hypotheses of Human Evolution, Luskin writes:

The missing link presently being touted in the media, Ardipithecus ramidus, has had more reconstructive surgery than Michael Jackson. Assuming that their "extensive digital reconstruction" of its "badly crushed and distorted bones" is accurate, what does A. ramidus (or “Ardi” as the fawning media is affectionately calling it) really show us that we didn’t already know? We already knew of upright walking / tree-climbing, small-brained hominids—that’s what Lucy, an australopithecine, was. We already knew that there were australopithecine fossils dating back to before 4 million years, and this fossil is only a little bit older. So what does this fossil teach us? Assuming all the reconstructions of Ardi's crushed bones are objective and accurate, this fossil teaches us at least one very important thing: prevailing evolutionary explanations about how upright walking supposedly evolved in humans, confidently taught in countless college-level anthropology classes, were basically wrong.

The Ardipithecus remains were painstakingly reconstructed over a period of ten years, during which clues about her morphology were extracted. Mr. Luskin is not correct in his assertion that we already knew about australopithecine fossils before 4 gigayears ago. The earliest clear evidence that we had for bipedality dated to around 3.6 mya. It is clear that bipedality was established by that time but we didn't have anything before that. The description of the Ardipithecus remains tells us that bipedality was incipient 4.4 mya.

He is also wrong about what was being taught. It has never been clear how bipedality arose and there have been competing models to explain its development that have been nothing more than hypothetical because we didn't have anything to test them on. The most popular model was the "forest/fringe" model in which bipedality arose as the climate cooled and the savannas expanded. The precursors of the Gorillas and Chimpanzees adapted to the forest proper, while the baboons and their ilk took to the grasslands. That left the area in between where a hominid could develop that could take advantage of both. Guess what? That model turned out to be wrong. So what? Now we know that bipedality arose in a forested environment and our models can proceed from that knowledge. That is how science works. It learns from its mistakes.

Luskin is also wrong about what else it tells us. It tells us that this early biped was also completely adapted to the trees, and was, thus, in a position to take advantage of the shrinking forests when the dessication began around 4 mya. We still don't know exactly how bipedality developed, but we know that it did.

Luskin also writes:

It’s rarely discussed, but there are a number of upright-walking, forest-dwelling ape-like species known from prior to 10 million years ago that are thought to be far removed from human ancestors. This implies that bipedalism in a hominoid does not necessarily qualify an individual as a human ancestor, and it also casts doubt on classical explanations for the evolution of bipedalism.

WHAT???? Which ape-like species is he talking about? There are absolutely no bipedal apes of any kind in the Miocene prior to seven million years ago. If there had been, this would have been huge news! He, of course, cites no information here. It isn't rarely discussed. Its not discussed at all!! I have written Mr. Luskin and asked him which remains he is referring to. I know it ain't Dryopithecus, Sivapithecus, Oreopithecus, Kenyapithecus or Gigantopithecus.

Luskin, correctly, does point out that there is some skepticism in the palaeoanthropological community about whether the case for bipedality holds up, notably from Bill Jungers at Stony Brook and Bernard Wood, at GW, in Washington, D.C., although Wood states that the head has better evidence for bipedality. This is, perhaps, true and we do need to be cautious about hanging our hats on one specimen, but the evidence, as presented by White, Asfaw and Lovejoy, is compelling. Luskin concludes thus:

So what do we have with “Ardi”? We have an extremely crushed “Irish stew” fossil that has undergone extensive reconstruction in order to become part of a PR campaign to make bold claims of ancestral status to the human line, even though at base its qualities are very similar to previously known fossils, and there's a lot of skepticism about the claims being made. In other words, we have the typical media circus that we find every time a new "missing link" is found.

For one thing, Luskin has just finished saying our models are wrong. The only reason that our models are wrong is because Ardipithecus ramidus isn't similar to other previously known fossils. That is why it is generating the buzz. The remains are completely, radically, different from the fossils that we have that come after, when bipedality is firmly established. The only reason it became part of a PR campaign at all is because it was so unusual. Hundreds of fossils have been yanked out of the ground in the last decade, none of which made the front page because they confirmed what we had already suspected about human evolution. Ardipithecus ramidus didn't. It suggested new things to think about and new models to work from. That is how science proceeds. Casey Luskin doesn't seem to like that.

----------------
Now playing: Peter Gabriel - It Is Accomplished
via FoxyTunes

Darwin Was Right

Or at least his grandson was. Apparently, one of the younger Darwin's ideas was that the movement and mixing of water between the equator and poles is influenced by sea life, who swim through the water. This was an idea that was largely ignored until recently. As a report appearing in PhysOrg notes:

Using a combination of theoretical modeling, energy calculations, and field observations, researchers from the California Institute of Technology (Caltech) have for the first time described a mechanism that explains how some of the ocean's tiniest swimming animals can have a huge impact on large-scale ocean mixing.

The idea was largely discarded because it was felt that the movement of the ocean would overwhelm any movement that was made by the fish. Not so, they say:"

Darwin's grandson discovered a mechanism for mixing similar in principle to the idea of drafting in aerodynamics," Dabiri explains. "In this mechanism, an individual organism literally drags the surrounding water with it as it goes."

Using this idea as their basis, Dabiri and Katija did some mathematical simulations of what might happen if you had many small animals all moving at more or less the same time, in the same direction. After all, each day, billions of tiny krill and copepods migrate hundreds of meters from the depths of the ocean toward the surface. Darwin's mechanism would suggest that they drag some of the colder, heavier bottom water up with them toward the warmer, lighter water at the top. This would create instability, and eventually, the water would flip, mixing itself as it went.

This has tremendous implications for evolutionary development. The movement of ocean currents has a large effect on continental temperatures which, in turn, has a large effect on the kinds of vegetation that grow and the kinds of fauna that live there. For example, it is likely that the expansion of the Mediterranean during the Miocene led to cooler temperatures in North Africa, specifically the Afar triangle. This led to reduction in forests and an increase in savannas. A group of late Miocene apes began to exploit the forest fringe area and established their own niche—these became the early hominids. I will be curious to see how this research pans out.


----------------
Now playing: Anthony Phillips - Wise After the Event (instrumental Mix)
via FoxyTunes