A Human Ancestor for the Apes?

Do we really need to consider turning everything upside down by considering the existence of a human ancestor for the apes? This suggestion definitely has the quality of blasphemy against religious doctrine. It just feels wrong and goes against our deeply held beliefs and understanding of the world.

However, this is exactly where the evidence leads.

Overall, I don’t expect that the entire anthropology community will suddenly abandon everything that has been taught for decades. However, my point is the following:

  1. We see the spine anatomy of a hindlimb supported upright ape in Morotopithecus, Pierolapithecus, Oreopithecus. The data is compelling and extensive – and I have detailed it in technical raw data form in my book: Axial Character Seriation in Mammals, which republishes my Harvard PhD Thesis. The underlying patterns are extracted and synthesized in my recent PLoS ONE paper “Homeotic Evolution of the Mammals, Diversification of Therian Axial Seriation and a Morphogenetic Basis for Human Origins” and in my Neurosurgical Focus article. The context in evolutionary theory is explained in my recent book “The Upright Ape: A New Origin of the Species” which has a foreword by David Pilbeam – currently Dean of Harvard College and certainly one the most knowledgeable and experienced paleoanthropologists in the world.
  2. We have evidence of an upright hindlimb supported Orrorin based on the femur and Sahelanthropus based on the skull.
  3. There is no convincing fossil evidence at all of a non-bipdeal hominoid outside of the proconsulid group.
  4. We have an early outgroup whose infants have innate bipedal walking (see the video Hominiform Progression). The Siamang video is interesting because of the innate bipedalism. As I point out in the video, John Fleagle has seen young siamangs of this age walk bipedally high in the canopy in Malaysia.

Cladogram of Hominoid Pelvic GirdleIt is typical to say that all of this is irrelevant and misleading and should be ignored. There was a quadrupedal common ancestor for chimps and humans and the human lineage suddenly and majestically stood up about 5-6 million years ago. However, I feel that there is no a priori reason why we must ignore all of the evidence for early bipedalism.
None of the skeletal evidence can ultimately distinguish between “short bursts” and long distance bipedalism as Kambiz points out in his post. My focus is on the character state and whether the crucial anatomical basis is a shared derived feature of a hominiform clade.

It can certainly be said that the siamangs only engage in bipedalism for short bursts, but that is also true of their brachiation. Similarly, the chimps and gorillas knuckle walk and the orangutans fist walk only in short bursts. However, the important point is that chimps, gorillas and orangutans seem to locomote in diagonal posture more than 90% of the time and only occasionally deploy a short burst of bipedal walking. I would argue that they have very bad spinal architecture for bipedal walking. On the other hand, hylobatids use bipedalism 100% of the time when they locomote on the ground no matter how long the burst of activity. If a hylobatid has to travel a long distance on the ground – it does not lapse into a quadurpedal gait – it just keeps walking bipedally. There is an important difference in the role of bipedalism as deployed by hylobatids and hominines as opposed to what we see in chimps, gorillas and orangutans.

This would be a morphogenetic origin for upright bipedal walking rather than an adaptive origin. Essentially, the origin of upright posture was not driven by any ecological scenario, but rather occurred suddenly as a result of a morphogenetic mutation in the Pax genes. Various descendant forms will have lived in various environments with variously optimized versions of primary upright bipedalism on large horizontal arboreal supports and on the ground.

It is certainly easier to assert that Morotopithecus was upright and hindlimb supported – based on spinal anatomy – than to prove it was primarily bipedal or a long distance walker. Gibbon Walking on a VineHowever, this is where the video showing the baby siamang learning to walk bipedally is relevant. Yes, you could argue that innate bipedalism evolved independently in parallel in hylobatids and hominines, but is also reasonable to consider that since this is so unusual, that it reflects descent from a common ancestor that had this feature. Essentially – an eight month old Morotopithecus baby would do the same thing that we see in the two descendant groups (hominines and hylobatids) – the baby would innately begin to walk bipedally as it’s primary locomotor pattern.

So – if the chimp-human split did take place 6 million years ago (as the molecular data suggests), then what do we do with Sahelanthropus which many believe was a full time upright biped but which lived 7 million years ago?

If you want a slow gradual evolution of bipedalism, you need to push the chimp human split back to say 8 million years. However, there is an alternative explanation. Upright bipedalism was already the primary means of locomotion in the common ancestor of chimps and humans – Sahelanthropus is ancestral to both lines.

What defines a “human?” I have taken the position that it is a body plan (bauplan). Most of us have accepted that early Australopithecines whose brains and skulls were chimp-like, should be considered human and not ape. When you find a fossil such as Sahelanthropus that has a “chimp-like” skull from the point of view of its face and brain, but has the skull base of a human (and presumably upright bipedal post-cranial anatomy) – how can you tell from the fossil if it’s an ape or a human?

The Hennigian cladistic approach lets us say that the isolation point between the chimp and human lineages – where hybridization became impossible – is the origin point of humans. However this means that the definition is arbitrary since ape and human would pretty much look identical at that time.

Illustrations of Hominoids

SNT Transposition

Another alternative is to stick with our current definition – a hominoid whose anatomy reveals that it is primarily an upright biped is a human. I have proposed the term “hominiform” to refer to a clade of hominoids that share the Morotopithecus spinal transformation (septo-neural transposition – in which the dorso-ventral plane of the body flips from ventral to the spinal canal to a new position dorsal to the spinal canal) and the styloid process is converted into a neomorphic hominiform lumbar transverse process. The Morotopithecus & Homo sapiens vertebraesynapomorphies would include innate bipedal walking in the infants.

Among hominiforms we have primitive “eubipedal” types (most Miocene and Pliocene fossil hominiforms, the hylobatids and the hominines) and derived “metabipedal” types (lineages of chimps, gorillas and orangutans) that have abandoned bipedalism as their primary locomotor pattern on the ground.

Sahelanthropus appears to be a human species that is representative of species in the line of ancestry to both the chimpanzees and hominines.

Aaron Filler, MD, PhD

89 thoughts on “A Human Ancestor for the Apes?

  1. For what it’s worth I had this posted a couple of weeks ago:


    A couple of comments I made there may interest you:

    “The species has been classified as Sahelanthropus tchadensis and it appears to be ancestral to the Australopithecus genus (and so to us). The big question is; is it also ancestral to chimpanzees and gorillas?”

    And “We can presume the common ancestor of humans and African apes was a bit like an Australopithecus or Ardipithecus and even more like Sahelanthropus. Chimpanzees may indeed be the least changed from the ancestral population and so possibly the common ancestor was like a chimpanzee. But we can’t say that humans evolved from chimpanzees. For all we know chimpanzees may believe they have evolved from us. Some people believe the unusual way the African apes move on the ground (knuckle-walking) indicates the apes may in fact have evolved from more upright-walking ancestors.”

  2. “This suggestion definitely has the quality of blasphemy against religious doctrine”

    That’s how cranks start their marvelous and “revolutionary” claims against the Establishment. Pity for Anthoropology.net. This kind of fringe science is ruining the site :-(

  3. It’s not fringe science. You can take the results of research at the Harvard Peabody Museum, accepted as a PhD Thesis, and a peer-reviewed publication accepted by one of the leading scientific journals – PLoS ONE and call it “revolutionary” “a pity” and ruinous – but that just shows fear of change. Can’t we all just keep the findings of science the same way they all were when I first learned it? If the new data doesn’t fit the old theories – I know you’re one of the advocates for ignoring an burying the data. But you are certainly not alone in that. Fortunately there is no ultimate comfort for scientists who fear change.

  4. I’m Catholic. I can’t imagine why conclusive proof that apes evolved from hominoids would contradict Catholic teaching or doctrine. If you maintained that apes evolved from homo sapiens, that would be interesting.

    1. Pavel, does bible say anything about apes coming from men? It may interest you that Quran suggests that

  5. “Fortunately there is no ultimate comfort for scientists who fear change”. Perhaps not, but history shows that the comfort can last for an unbelievably long time.

  6. “You fear change”: another guaranteed crank sentence. I hope we don’t have to read the typical auto-comparisons with Galileo.

    “I know you’re one of the advocates for ignoring an burying the data”

    Yes, I am an anti-scientific super villain. You are the galilean hero.

  7. El PaleoFreak – not to worry. Fortunately, a wide array of paleoanthropologists and evolutionary biologists have actually read the PLoS ONE paper and other publications and it has all been well received in the academic community if not universally accepted. I have a podium presentation at the next Amer. Assoc. of Phys. Anthro meeting. I’m certainly not having trouble getting published. One of my books is from Oxford University Press -so no I won’t be making any auto comparisons with Galileo. I was more surprised by your outburst about this being crank fringe science – presumably without actually bothering to first read any of the primary data. I apologize if you actually have read the material, but I understand you may not have time to go beyond the opening paragraphs of the blog.

  8. Three days ago your work is like “blasphemy against religious doctrine”, going “against our deeply held beliefs and understanding of the world”. Today it is “well received in the academic community if not universally accepted”.

    Wow! That’s probably the fastest scientific revolution in History. Congratulations!

    A 21 million years old macro-mutant individual was the first human. Chimps and gorillas evolved from humanity. Universally accepted… OK.

  9. If this evidence holds up, I think it can be a corrective to the typical human need to consider ourselves the “peak” of evolution. It might better convince at least some people that we are part of life, not the end result of it, and all that that implies. Such thinking is as blinkered as that of those who thump for intelligent design, and conceals a secret prejudice in favor of that dangerous, gratifying notion, “progress,” still unpleasantly prevalent in our society. I will follow this with great interest.

  10. El Paleo – I am very clear in making the introductory point that when you first hear this it has the feel of e a deeply held belief being challenged. I go on to point out that the data is leading this way. Because most scientists go through the data before attacking, it has been well received. If you attack before you read the data then you are … well.. El PaleoFreak

  11. Data, data, data. You keep talking about data. This is not about data, it’s about certain claims, and the pompose way they are made. It’s about particular interpretations and conclusions on certain set of data. The data don’t say we have to redefine “biped” or “human” concepts. The data don’t say anything about a macromutant ancient “human”. You are saying it.

  12. Little doubt prof.Filler is correct in saying that the early apes c.20 Ma had an upright spine, but that doesn’t mean they were “bipeds”. Miocene apes are typically found in coastal/swamp/flooded forests (eg, Heliopith=Afropith, Austriacopith=Griphopith, Dryopith, Oreopithecus…), so they spent some time in the branches, some time in the swamp (as proboscis monkeys do & Ndoki gorillas, only more frequently), where the upright spine was obviously advantageous for wading on 2 legs & for grasping branches or fruits above the swamp & for hanging on the branches. This also explains many differences between monkeys & apes: tail loss, less lumbar vertebrae, larger size, broad thorax & breast bone, arms lateral of body, etc. For discussions of this “aquarboreal theory” (aqua=water, arbor=tree), see http://groups.yahoo.com/group/AAT

  13. I’m just a layman enthusiast, but I’ve always prefered this hypothesis of evolutionary “inertia” for human bipedalism.

    Human wide shoulders and thorax also seem to make more sense (to me, a layman) as something that comes “directly” from arboreal ancestors which used to be hanging on and between branches, rather than something that would evolve following an upright posture. I can’t see why the broader shoulders would be an important/likely adaptation for upright posture or succeeding it; I think that we could do very well even with a upper body that was originally adapted to knuckle walking (but, in the other hand, it could have evolved as a by product of overall neoteny, I sloppily guess).

    I think I got this thing of upper body more similar to “branch-hangers”‘ from Pilbeam’s “ascent of man”, which I think dates from when it was thought that the human lineage had split prior to orangutans, gorillas and chimpanzees. And, there’s also JH Schwartz, which probably points to similar things on anatomy, even though I prefer to ignore everything else he may say.

    This “fake” quadrupedalism of chimps and gorillas also seems more likely (to me) to evolve convergently by natural selection, as quadrupedalism is more efficient in many aspects. Even chimps, however, perhaps bring some clues of a past bipedal gait. I’ve read something recent saying that some of them actually have more efficient bipedal than quadrupedal gaits, regarding energy comsumption. It’s something that varies individually with learining/practice, if I recall.

    There was also a theory (unfortunately I don’t recall the theorist, but I think I’ve read about it in either Edey and Johanson’s “Lucy” or Foley’s “humans before humanity”) that chimps or maybe chimps and gorillas were initially more human-like (not specifying how more human-like, as far as I recall), and what happened was some sort of character displacement by natural selection. Wherever I’ve read that, it said that it’s no longer believed, but does not seem very bad to me.

    I think that, despite of being somewhat less parcimonious the independent evolution of knuckle walking in chimps and gorillas versus evolution of upright posture in humans, when seen in a larger context it’s more parcimonious.

    Evolution by natural selection – an onerous concept, as G. Williams put – is more evenly distributed by the lineages, and humans cease to be such a “deviation”, which differentiated exceptionally. A recent research actually suggests that chimps have evolved somewhat more than humans by NS anyway, which I think that also may favor this point of view.

    And, furthermore, about the human-chimp split, how’s that deal with the 10 million years old gorilla, that was thought to possibly imply in a early split between humans and chimps? (due to molecular clock’s adjustments).

    I don’t know if it was finally regarded as a necessary adjustment, but however, as far as I know, this anticipation of the split may be more in accordance with the fossil evidence we have (or once had, perhaps it changed by now), which used to point to an earlier split (~8Mya) than molecular data suggested (~5Mya).

    So, seems that quite a few “outdated” ideas are becoming somewhat “fashionable” again.

  14. I am a zoologist and I developed, 20 years ago, a theory called “initial bipedalism” about the descent of apes (and other quadrupedal mammals) from bipedal human-like forms, that developed from originally erected aquatic forms. So I totally agree with Dr Filler’s assertion that chimps and gorillas have descended from early bipedal “hominiforms”!

  15. Actually the “data” (there’s that pesky word again!) has been demanding a new conceptual interpretation for a long time. A very long time. I’m only an “armchair” paleo freak myself, but I have browning notes of my own from 20 years ago where I wrote in the margins “if bipedalism didn’t evolve twice, then quadrupedalism had to.” We could of course just give up on explaining the fossil record, but what fun is that?

    The finds of Ardepithecus, Orrorin and Sahelanthropus have made it clear for some time that the last common ancestor between chimps and humans was almost certainly a biped. How likely is it that the LCA stood up on two legs for the first time, just in time to immediately diverge into two lines, one of which immediately “reverted” to quadrupedalism? Either we’re looking at the fastest “do-over” in evolution, or bipedalism extends back further into antiquity.

    Any sharp line we try to draw between humans and the other apes will always be entirely subjective. Bipedalism sufficed for many people for many years, but that’s out the window. The dust will be a long time settling.

  16. Human uprightness implies much more than mere bipedalism. It is a unique feature characterized by the fact, that in the normal upright position all the centers of gravity of separate body parts (head, torso, upper arm, forearm, hand, thigh, lower, leg) are located in the same frontal plane, producing a unique pattern of overall mechanical equilibrium. This fact was already discovered at the end of the 19th century, by Braune & Fischer. Even H. Erectus or H.Neanderthalensis are lacking this pattern (as far as the head is concerned). See my book:

  17. Title should be “A bipedal ancestor for the apes?” Present (sensationalist) title also implies that modern humans could interbreed with the common ancestor of humans and chimps, but modern chimps could not. And so on. These are sweeping claims I presume Dr. Filler is uninterested in pursuing.

  18. To omnivore – This is a question of definitions and I have addressed it more specifically in my blog on the Oxford University Press site – Redefining the Word Human: (http://blog.oup.com/2007/12/human/).
    I am not saying “Homo sapiens” which is a species. We are talking about what to call an “animal” such as Sahelanthropus – is it an ape or is it an adjectivized human (e.g. “proto-human”) which is still “some kind of human.” We can also distinguish between “sapient human species” and perhaps “pre-sapient” or “pre-symbolic” human species. The problem comes down to the fact that Australopithecus afarensis probably should not be called an “ape.” These are obviously colloquial and non-cladistic terms, but I argue that they refer to our perception of body plan. We have dodged the issue by using definitions that require complex speech etc. but these clearly exclude the “early, ancestral, or proto-” human species.
    Aaron Filler

  19. Dr. Filler:

    I have no problem with – but am agnostic about – the model of both hominid bipedalism and great ape knuckle-walking evolving from the “bipedalism” (specifically, arboreal brachiation and terrestrial bipedalism) of arboreal Miocene apes like Morotopithecus and Oreopithecus. I also accept the importance of discontinuous major developmental change in macroevolution.

    The “bipedalism before knuckle walking” model (which is more to the point than “20 million year old human” or” apes evolved from humans”) may well be correct. And if you are right about that, you deserve plenty of accolades. Even if your model is wrong (and hominids evolved from knuckle-walking ancestors who evolved from “bipedal” Miocene apes), your developmental approach emphasizing spinal evolution is a significant accomplishment in the field of paleoanthropology.

    However, I have a big problem with your use of the term “human” (or “humanian”) to describe these bipedal Miocene apes.

    Your argument that spinal characters ought to be determinative of human status is unconvincing. You say is that “human” status should be based on body plan, yet your definition does not mention a remarkable feature of the human body plan – our greatly expanded brain relative to apes.

    Putative biped Miocene apes are human? I don’t think so. In addition, I consider australopithecines to be bipedal apes. Hominids, yet apes. Only members of the genus Homo deserve to be called human based on brain, behavior, and ecology. The real transitional species between human and ape is H. habilis, not Morotopithecus.

    Is Morotopithecus today’s Ramapithecus? (That is, the “earliest human” who wasn’t?) We’ll see.

  20. As a practicing scientist, I’d strongly recommend that you ditch the whole “let’s redefine the word ‘human'” angle and focus on your actual claim, which is a bipedal ancestor for the apes. That’s clear, and it’s clearly science. This bit about what “human” should mean makes you look like a loony, and it has nothing to do with your scientific contribution. Get famous by shaking up the science using the old guard’s terminology. Then argue for a terminology change.

  21. In addition, I am not convinced that Morotopithecus and the rest ought to be called “bipeds” any more than so-called “eubipedal” hylobatids do. Sure, they are bipedal when on the ground – but they are primarily arboreal. (Sifaka are bipedal on the ground – should they also be described as bipeds?) With perhaps equal justification Homo sapiens could be called “quadrupedal” since we use all four limbs when swimming or climbing trees. Rather than throwing around terms like “biped” (much less “human”) we should acknowledge that brachiating hominoids have erect (or at least diagonal) posture. (That is part of what makes knuckle-walking so distinct from cercopithecoid quadrupedalism.) I think “brachioforms” is a more appropriate name for this group than “bipedal apes,” “hominiforms” or “humans.”

    Lay people don’t know what you mean when they see headlines about apes evolving from humans. They see those kinds of headlines and think chimps and gorillas literally evolved from us or something like us.

  22. A circle-the-wagons mentality has led to a rigid opposition to saltational or punctuated models of morphologic change since the 1850’s. Darwin was afraid the public would see acts of God as in Sir Richard Owen’s “serial acts of creation.” He insisted on only gradual change so the public would not get the wrong idea. Insisting on a given position to avoid the evidence but also avoid alarming the public or aiding the predatory creationists is never right if it forces scientists into models that aren’t optimal.
    In “The Upright Ape” I cover in detail how we arrived at our current usage of “human” in paleoanthropology.

    We do like to hide behind latin to avoid alarming the public. See Wolpoff et al in their comment in Nature (2002 – v419:581) “Sahelanthropus or Sahelpithecus?” But when Ann Gibbons – a paleoanthropologist who writes many of the news columns on paleoantrhopology for Science – wrote about the discovery of Sahelanthropus – she entitled the book “The First Human.” She’s talking about the species that may be ancestral to the chimpanzee lineage. She is following in the tradition of Don Johanson and Tim White who promoted “Lucy” in this fashion. Russell Tuttle has also covered the issue in his 2006 article “Are human beings apes?” in the Ishida et al volume on human origins.

    I am specifically departing from Sir Arthur Kieth’s “Hylobatian” model because it implies an ecological scenario for our upright origins – that it derives from a lineage exploiting a niche available to a brachiating hominoid. Instead I am expressing the consequences of a morphogenetic basis for human origins. Our upright form derives from a homological discontinuity – the hominiform lumbar transverse process (LTP) is based on an arch structure – the anapophyis or styloid – and therefore carries the longissimus attachment. This is distinct from the typical catarrhine condition of a rib based LTP that does not have muscle attachments.

    The box-like cross section of the human LTP and the LTP in Morotopithecus is structured (as the human trabecular pattern shows) for hindlimb supported upright posture. This is not about brachiation, it’s about a morphogenetic origin of a bipedal lineage or clade I term hominiforms. We do not know that they were arboreal and it doesn’t matter if some were. We can’t ignore morphological evidence just because we haven’t thought of a convincing ecological just-so-story to justify it.

    The term “proto-human” reflects what I call an “Aristotelian logical error.” Obviously, our ancestral species are not just like us so they can’t fit into our category. This is further aggravated by insisting that australopithecines are bipedal apes and that the expanded brain of Homo habilis is the first feature usable as the determinant of “humanity.”

    Terry Deacon (The Symbolic Species) is focused on the onset of symbolic thought as the basis for linguistic communication as the determinant of humanity. This probably excludes Homo habilis. One of the comments above also suggests that Homo erectus needs to be viewed as an ape as well.

    The founding hominiform lineage may have been a terrestrial upright biped that was not an arm swinging brachiator. If you want the whole symbolic linguistic package to define humanity vs animality, you may end up including only Homo sapiens sapiens – with language, art etc. If we accept Sherwood Washburn’s premise – that has been the basis of most scientific antrhopological models since the 1950’s – then it is primary bipedalism that distinguishes the human animal from the ape.

  23. Evolution doesn’t say we are the pinacle result of evolution, or that they are an end to evolution.

  24. I am sure that you have heard the oft quoted wife of a London aristocrat, upon hearing Darwin’s claim that man descended from apes, reponded, “My dear, let us hope that it is not true, but if it is, let us pray that it may not become widely known.” I appreciate the fact that you have noted above that this same “circle-the-wagons” mentality is prevalent in the scientitific community as well. I would contend that another clear short-coming of the scientific community is the unadmitted drive of today’s scientists to be as provocative as possible.

    The question is not about suppressing the facts or avoiding alarming the public but rather how to pump up the shock-factor of whatever theory or premise is being exposd. Certainly, to state that “Evidence exists for a bepidal ancestor to apes” does not quite have the same shock factor as a stating “Apes evolved from Humans”. The insinuation that you are only being scientifically honest by not allowing your theory to be influenced by whether or not it “alarms” anyone seems to me to be disingenuous. Search your motives. IS your reason for using “human” really based on current accepted usage of the term in the scientific community or is it your attempt to back into an answer that makes for the best book title?

  25. Paleoanthropology has been poorly served by a drive to lay claim to the earliest “human.” Henry Fairfield Osborn’s “pithecophobia” that led to his endorsement of Eoanthropus. Louis Leakey’s dubious inclusion of habilis in Homo. Pilbeam’s Ramapithecus. Johanson’s characterization of Lucy and claims for her implications (scientists had already long known that australopithecines were cranially apelike and fully bipedal. In addition, Zihlman was right about Lucy.) Somehow, paleoanthropologists keep identifying direct human ancestors – while banishing discoveries made by colleagues to side branches. In addition, these formulations have biased artistic reconstructions, resulting in pre-erectus hominds that are implausibly human-looking. (This tendency has been curbed since the seventies.)

    True, there is a tradition of somewhat whimsically calling humans “naked ape” or “third chimpanzee,” and deeming every putative direct human ancestor that likely walked on its hind legs “man” or “human.

    What you have demonstrated is that Sherwood Washburn’s premise was wrong, and bipedalism alone is not what distinguishes the uniquely human lineage – the lineage that includes only us and no other living species – from apes. The spinal innovation criterion of “humanity” is as arbitrary as any other discontinuous change that occurred in humanity’s entire evolutionary lineage prior to our split with Pan. And if we had evolved from knuckle-walking ancestors, would that make us pongids? Or hylobatids, if Keith were correct?

    At the very least, only forms that postdate the Pan-Homo split should be included in even a colloquial “human kindred,” bipedal or not. (I know, early hybrization complicates the picture a bit.) If Morotopithecus had somehow survived to the present and we had always known the species, it would be kept in zoos and used in entertainment, not regarded as “human” – not even by biological anthropologists – just because it walked on its hind legs. Even TV and movie apes do that.

    So we have one solid criterion of even an overly inclusive “human kindred”: our side of the Pan-Homo split. What about “human”? Do we need to identify the origin of language, or even less justifiably, define humanity based on the Upper Paleolithic revolution? Not at all. It can be done on behavioral ecological grounds, a suite of features that distinguishes our unique clade. Regularizing tool-making, long range travel, cooking, hunting of large prey, morphological-life history indicators of humanlike sociality (e.g. reduced dimorphism). That disqualifies the apelike habilis, who should have been banished from Homo long ago. And soon, the developmental-genetic basis of changes in the brain will be better understood, including discontinuous events, and these genetic changes will be correlated with behavioral ecological features. (Also, I have also long suspected – and accumulating evidence vindicates – that the cognitive differences between Homo sapiens sapiens and Neandertals and other archaics has been wildly overestimated.)

  26. Sherwood Washburn’s premise about the definition of humanity in bipedalism has been a core tenet of paleoanthropology for more than 50 years. When I first realized the implications of the Moroto vertebra in the 1980’s I was able to correspond with Washburn and he accepted that he may have underplayed the importance of bipedalism before the chimp-human split.

    As I point out in “The Upright Ape,” Washburn’s formulation was a defensive response to Irven DeVore’s PhD thesis. DeVore and Tuttle – both of whom were Washburn’s students and both of whom were my advisors – understood the origin of this definition of humanity and looked to direct me to focus on the spine to try to test the validity of Washburn’s hypothesis. This is also why David Pilbeam put the Moroto vertebra in my hand and asked me to analyze it in the first place.

    The definition of humanity is not a shock factor claim – it is one of the the core subjects of paleoanthropology. Because the outcome of this three decade project has the result of overturning Washburn’s hypothesis, it is appropriate to address the issue head on.

    It is not the case – as Colugo suggests – that the spine characters are equivalent to any other we may choose. This is because the impact of homeotic genetics shows that early changes in the principal segmental morphogenes in the Hox and Pax families are key to much of body plan evolution in the mammals. Also, Colugo may not be aware that the SNT change described in the original post and in the PLoS One article is part of a suite of changes that appear to be linked to the Uncx4.1 gene. In the undulated mouse mutant – a single gene change pushes the horizontal septum dorsad in the spine, but also results in an antero-posteriorly flattened chest and repositioning of the scapulae posteriorly. Pax and Hox gene changes are often massively pleiotropic – they affect many aspects of morphology at once. In this case, a number of features of hominiforms which we have attributed to gradual independent ecological pressures may have all change at once on a morphogenetic basis.

    This is what I mean by a morphogenetic basis of human origins.

    This ties in with the issues raised in the comments about limiting the term “human” to those species following the chimp-human split which meet certain intellectual criteria. The Hennigian paradigm is that when a small founder population splits off to found a new species then the parent species is considered immediately extinct and there are now two new daughter species. This is point when a post-split human lineage could be considered to have started.

    I cover this issue of species concept in The Upright Ape in some detail. Ernst Mayr thought this was an unbiological abomination. The parent species would look the same and have effectively the same gene pool when a new founder species split off. He objected to calling the main lineage a new species an the parent species extinct since the parent species and at least one of the daughter species were exactly the same.

    This is my point about having a human ancestor for the chimpanzees and possibly other modern ape lineages. If the pre-split main species and the post-split main species are identical genetically in every way, it greatly offends Mayr’s view to consider the post-split creatures humans and the pre-split creatures apes. This really makes apes and humans the same.

    I have suggested that most of the major body plan innovations we see at 7 million years ago had appeared in Morotopithecus by 21 million years ago as a result of a major morphogenetic event that generated the primitive hominiform body plan – an upright bipedal species with five or six lumbar vertebrae.

    I then propose a string of descendant species in which there was typically a relatively primitive generalized hominiform body type – that is the human body type. The first equally profound change to strike this chain of species was the brain size increase we first see clearly in Homo habilis.

    To insist that there can only be one kind of human species and it has to be pretty much just the kind of human we are – simply is a way of trying to restrict the term “human” to just our current species of Homo sapiens. This position – that australopithecines are not proto-humans because of their small brain size – could have been proposed by Washburn. It is a long time since Dart’s original discoveries that showed australopithecines had chimp-like brains. There is nothing we know now that makes it any more appealing to make Homo habilis an ape.

    However, the new evidence inexorably shows that the common ancestor of the chimp and human lineages appeared to have a body plan more similar to our human body plan than to a chimp’s body plan.

    This is why I have identified the body plan as identifying the human animal and reccomended adjectives to define and distinguish the various subtypes. I have also provided a collection of synapomorphies – shared derived features that provide a usable morphologic definition of a human. A paleontologist who has found a totally complete skeleton of an eight million year old hominiform or a three million year old hominiform has to be able to tell whether the species was ape or human and only a morphological definition can accomplish that.

    Aaron Filler

  27. 1) There are a number of homeotic transformations with pleiotropic effects in our evolutionary lineage, as far back as one wants to go. That change that you discuss is not arbitrary in terms of orthograde hominoids. But it is in terms of identifying human status. It is too inclusive because it is too primitive. A better character – because it more derived and hence more exclusive – would be erectus (or even, arguably, habilis) brain expansion. (By the way, why no mention of Richard Goldschmidt – who is useful, in his proper place.)

    2) What is Dr. MacLatchy’s current assessment of the locomotor behavior of Morotopithecus? Has she changed her mind?

    My quarrel is really with your use of the word “human.” But as I said, your analysis constitutes a significant contribution whatever the sequence of locomotory evolution turns out to be.

  28. Don’t you see what you have done? You have dethroned bipedalism in paleoanthropology*. For a long time a major question in human evolution was whether bipedalism or encephalization was the more critical evolutionary change that enabled the evolution of humanity. For decades that question appeared to be settled with the discovery, description, and acceptance of Australopithecines. Since you have argued that our lineage’s bipedalism long predates the chimp-human split, then it can no longer be the premier distinguishing characteristic separating humans from apes. And determining which features make humans different from apes and when and how these evolved was a major project of human evolutionary biology. If bipedalism is a primitive feature, it is like taillessness, Y-5 molars, or any other primitive feature that fails to distinguish us from apes. (It’s just a feature that extant great apes happened to lose.) The australopithecines are more clearly seen as yet another African ape radiation, one that happens to postdate the Pan-Homo split. Citing decades-old tradition (within a much longer history of human evolutionary research) is not sufficient for the retention of bipedalism as the central distinguishing feature.

    Bipedalism is dethroned. That leaves encephalization. This is the aspect of the human bauplan which is most critical to our evolutionary story.

    *That is, if you are correct.

  29. ‘Bipedalism’ is not precise enough a term. Birds are also ‘bipeds’, as was Tyrannosaurus Rex. Gibbon bipedalism is not the same thing as human bipedalism.

    Human ‘bipedalism’ is of a very special type, characterized by the projection of all the gravitation centers of the body parts into a single frontal plane. This special condition I call ‘uprightness’. We should think of bipedalism, not as a single Merkmal, but as an evolutionary process that proceeds with jerks, and reaches completion in humans.

    Evolution in primates seems directed towards uprightness. Monkeys already bear more of their weight on their hindlimbs, as compared with a dog or an elephant, for instance. Dr. Filler identified an important intermediate stage in this process. Uprightness with exception of the skull is present in Homo erectus or Homo neanderthalensis. Only Homo sapiens s. has developed full uprightness, including equilibrium of the head.

  30. Colugo, I definitely think your interpretation has merit, though as an archaeologist and not a physical anthropologist, I come from a background more willing to think of Australopithecines as essentially apes.

  31. A very sensationalist headline, seemingly designed to bait anti-evolution fundamentalists.

    But I guess “Bipedal Ape Ancestors Evolved Into Modern-Day Quadrupedal Apes?” doesn’t have quite the same zing…

  32. In “The Upright Ape” I do look into the anatomy, embryology, physiology and motor programs that underly a variety of types of bipedal locomotion in animals including dinosaurs, birds, running lizards and even some insects. In defining humans, it is precisely a matter of the role of bipedalism in hominoids and not bipedalism in general.

    Also, in the Neurosurgical Focus paper (with a link at the beginning of this blog post) I cover the various anatomical modifications of anatomy that optimizes bipedalism in australopithecines and various species of the genus Homo. The Hominiform Progression video (see link above) shows hylobatid bipedalism and helps provide a feel for some versions alternative to our own.

    There are various different ways of aligning centers of gravity, but there really is no option for “off balance” forward stooped bipedalism. I see patients referred to me for help who have had incompetently performed spinal fusions so that they can’t stand in a fully balanced vertical upright position and it is incredibly painful – the spinal muscles are in constant struggle and any perturbation caused by lifting or turning is very difficult to accomodate. This is not just a matter of pathology in modern humans – I don’t think you can have a functioning primary mode of locomotion that is continually off balance and demanding intense muscle activity to maintain uprightness. I therefore consider any upright bipedal hominoid to have had a well balanced bipedalism well suited to its usual locomotion.

    One of the images in the post above shows a gibbon walking up a vine – something that 99.999% of humans certainly can’t do. From the gibbon’s point of view, humans are handicapped by our fused-in first toe and are unable to walk bipedally in many natural substrates such as narrow branches and vines.

    The hominiform synapomorphies that underly our bipedalism are not found in the extinct proconsulid apes. They had tail loss and the Y-5 molar, but had more monkey-like quadrupedal style spine and limbs (see the cladogram in the post). Therefore this is not just another distant primitive feature of all hominoids.

    I agree that my conclusions further decouple the origin of our bipedalism from the origin of our human intellectual capacity. It is now even more clear that these two aspects of human existence are not directly intertwined in evolution, but this could be seen from what we have known for decades from australopithecines.

    However, I would not “dethrown” bipedalism. Primary bipedalism is extremely rare in mammals or even in the entire synapsid radiation over more than 300 million years.

    We have tended to view the australopithecines as being transitional forms along the direct short path from ape existence to fully human existence – carrying, throwing, and complexly thinking. Instead, I would focus on understanding “pre-sapient” human species on their own terms. What is the impact of the bipedal body form on competition with meta-bipedal apes and quadrupedal monkeys? In “The Upright Ape” I pick up Gould’s theme of hierarchical evolution to emphasize that not all evolution relates to competition between individuals in an interbreeding population. Speciation and body plan innovation produces new versions of an animal – species and even higher order groups (e.g. mammals vs dinosaurs) can compete with each other based on their unique biologies.

    What this results in is forcing the scientist to consider that for the vast majority of existence of the human body plan, it has been a very successful body plan. This is without the special intellectual capabilities shown by humans from the genus Homo. For 19 million years there have been successful species of “pre-sapient” human hominiforms (terrestrial primary bipeds) which have spread from continent to continent. Only in the last two million years has brain size expansion resulted in “sapient human species” able to eradicate the “pre-sapient” human species of which none survive.

    There is no definite answer. However, I feel that by focusing excessively on our intelligence, speech and culture, we tend to miss some of the aspects of our upright bipedal body plan that are also essential to our humanity. For this reason, I would not discard the “non-sapient” human species. I would include as many of them as there are from Morotopithecus onwards as humans, and refocus our anthropology – as Lieberman and other have done recently – to look at issues like the energetics of long distance walking and other aspects of hominiform bipedality – to better understand who we are.

    Aaron Filler

  33. Points well taken, Dr. Filler. I broadly agree with you about hierarchical selection, homeotic change, and the bauplan approach.

    Let me suggest a new meme: Replace the term “human” to describe the orthograde hominoids (AKA modern apes, eu- and metabipeds, advanced hominoids) that emerged about 20 million years ago with the term “orthoapes” and reserve “human” for the group with greatly increased brain size (ergaster/erectus, archaics, modern sapiens). Orthoapes. Rolls off the tongue, doesn’t it?

  34. I find it hard to believe that someone would actually argue that the term “human” should be applied simply based on the fact that a hominoid mammal walked on two legs, let alone upright. Regardless of whether or not the term is defensible from an anthropological or physiological stand-point or not. If your neighbor broke into your house, killed or incapacitated you with blows, and then dragged your daughter to his own place to forcibly mate with her, most rationale people would consider such a species “inhuman”? And yet this activity is common, natural and expected of the same ape species which Dr. Filler proposes to term “human”. I think the term “human” deserves a bit more dignity than that.

  35. truthvitamin – with all due respect, are you describing known behavior of some extinct species? There certainly have been modern humans who have committed crimes such as you describe, but that doesn’t allow us to deny the term “human” to our own species. I think what you mean is humane and inhumane behavior. As I’m sure you know many humans have committed many horrible crimes. Sometimes, entire nations engage in publicly supported genocide, etc.

    It would be nice to have a way to classify the ethical level of a hominiform species, but your definition would seem to exclude Homo sapiens sapiens as well. There has always been a mindset that compares the noble god fearing, devout caring church going human to the savage animals. This notion has a powerful effect and helps drive the creationists revulsion with the idea that humans could be related to apes. However, apes also display noble and sensitive behavior and modern humans can display vicious behavior. That is we have police forces and a millions of people incarcerated for crimes in this country. It is interesting to reflect on this, but I don’t think it provides a way to determine how the word human can be used in describing species.

    If gibbons and siamangs proved to be wonderfully monogamous and totally non-violent towards each other, would you call them human on that basis?

  36. Dr. Filler – You seem to be arguing from the exception and not the rule. To say that a species may, from time to time ,exhibit a particular behavior does not qualify it as being exemplary of that behavior as a general rule.
    While you are trying to justify your own personal anthropological derivation of the term “human” as it relates to a species, you cannot disregard how that term will be viewed and perceived by the reading public. I am only commenting on the generally accepted semantics of the term, be it in science or the general public. My point was simply that the correct use of the term “human” can be best derived from looking at the use of its opposite, in this case, “inhuman”. Whether that behavior is by an ape or a human, it still carries the same meaning. To my knowledge, at least, no one uses the term “inhuman” to describe NOT walking upright on two legs. (N.B. the terms “inhuman” and “inhumane” do have slightly different connotations)

    With all due respect, the title of your entry “A Human ancestor to the Ape” seems to me to be at best misleading and at worst insulting. I feel as though use of the term “human” deserves more dignity than that and to be quite frank, your commendable research and noteworthy findings deserve more dignity than that. Based on your further elaboration on this issue, it seems clear that your true intent was not to present a learned display of the facts but rather to simply further fan the flames of “the creationists’ revulsion with the idea that humans could be related to apes”. In the latter, you seem to have succeeded.

  37. Truevitamin – you may not have read through the replies above. In biological anthropology, the most widely accepted demarcation of proto-human vs ape derives from Sherwood Washburn’s position that after the chimp-human split, bipedalism developed in the proto-human lineage. He relied on bipedalism to make it possible to assign fossils to the human lineage vs the chimp lineage. If bipedalism predates the chimp-human split, then that definition needs to be reassessed and that is what I’m doing. Particularly as it affects Sahelanthropus – a species already categorized in the proto-human lineage on conventional criteria appears to also be ancestral to chimps. This is why it appears that there may be a human ancestor for at least some of the apes.

    I presume that the violent behavior you described refers to chimpanzees. That doesn’t help answer the question of whether to call Australopithecus or even Homo habilis apes or early/proto humans. It’s not about insults its about classification and morphology. I also make the point above that you can’t test hypotheses and make decisions in science based on what effect it may or may not have on creationists. If a creationist believes that all species were created in their current form about 6,000 years ago, none of your concerns about dignity really matter.

    If you believe Hobbes – then human life was nasty brutish and short before government established the principal of monopoloy of force. If you believe Rousseau then man was “good” in a state of nature but was corrupted by society. You can look at the Yanomamo to support Hobbes or look at the Kung to support Rousseau. We’ll never know which met your “majority ethical” criteria in which pre-Homo sapiens sapiens species.

    At one extreme we have the Osama bin Laden’s Wahabi sect who believe that all others are so ethically inferior that God will rejoice in the brutal slaughter of all non-Wahabis because they are more or less sub-human. They are all about optimum human dignity.

    I think these are certainly valid issues, but I can’t accept your argument that only “good” modern members of Homo sapiens sapiens can be proven to have sufficient “dignity” to be considered human.

    As books like “The Last Human” and “The First Human” show, it certainly is not my idea to include australopithecines and Homo habilis as (adjectivized) human species. I do believe that there is a human body plan and that it has a lot to do with being human and that this type of creature has a long history – back to Morotopithecus. It is important to understand that we retain many of the longstanding or primitive anatomical features that have been abandoned or evolved away from by various ape lineages. Increased brain size and symbol based language are very important to our species, but it does appear to be plausible to argue that the “human” type of body plan does include a wider range of species than just our own.

    Aaron Filler

  38. I read some passages from The Upright Ape. Theoretically the book is cutting edge, like the work of Terrence Deacon. The discussion of cellular selection is excellent.


    1) Are living gibbon and siamang species human?

    2) Would Washburn and his peers have made bipedalism the primary criterion of human status had they not believed that bipedalism evolved (or re-evolved) after the Pan-Homo split, rather than being the primitive condition of modern hominoids?

  39. I agree with the opposition with this usage of “human”. I think that the problem of gibbons and orangutans was well pointed. But perhaps some people would agree with a more inclusive usage of “human” that would embrace most of the apes (I think of Goodman and perhaps Singer). But perhaps chimps and gorillas could also be considered as “secondary inhumane”, like some dinosaurs are hypothesised by some to have been a lineage of birds in which evolved secondary flightlessness.

    While I don’t really care that much, for myself, I think that worth some concern the mental image the term creates for some part of the lay public, as was pointed by some people. And… specific segments of crackpottery, like creationists who may think that it would support the idea that other apes descend from Homo sapiens from the ark, and this other thing up there with the guy who argues that humans evolved in the water from some sort of buoyant big-brained pikaia and are the common ancestors of all terrestrial vertebrates… I have the gut feeling that a different phrasing like “gorillas and chimps evolved from bipeds” or something like that would be less prone to spark this sort of things. But maybe wouldn’t have much difference.

  40. I have believed now for some time (10 years or so) that indeed apes are the descendants of man. I’m not a p.h.d or anything like that but i am a student of the mysteries. Your theory is certainly interesting to me. I read Madam Blavatsky’s anthropogenesis and cosmogenesis about 10 years ago and have since researched many of her ideas (I am not a theosophist but I am a student of ancient religion and philosophy). In fact I must say the concept she put forth , which is the topic under discussion here, is actually an acceptable if not necessary conclusion in light of many ancient mystery traditions including that of the judeo-christian religions. In my research I have come the the conclusion that the bible in specific refers to a race of man that lived on the earth and founded technologically superior civilizations millions if not billions of years ago. This early race of man was responsible for administering the evolutionary process of all life on earth throughout the ages. Of course they most likely were not in the form that mankind appears now in their earliest state of terrestrial being, but gradually perfected there form until at last reaching the state that mankind appears in even to this day. I know these ideas are considered pseudo-science by the common standard of our present era but i think if you were to take the actual scientific data available to us now and correlate it with the various mythological histories of the different cultures around the world you world begin to notice a certain agreement between the two fields of study. Personally I think your on the right track… I hope the fact that I am a mystic and am in agreement with your observations doesn’t lend to the devaluing of your good reputation, but I’m happy to see someone looking a little deeper than the surface to find truth regardless of the popular opinion.

  41. “This suggestion definitely has the quality of blasphemy against religious doctrine.”, you said. But evolution does not completely go against one religion and that is Sikhism, world’s 5th largest religion.

  42. Would like to hear more from Jos Verhulst on the animals center of gravity and how our human C of G has become directly in a vertical line. Which was first – vertical or horizontal? Etc.

  43. I’ve read the artcle and most of the comments and it’s very interesting.
    Filler has demonstrated that the term ‘human’ applied to our bipedal ancestors is not necessarily wrong. I still find it, however, at least confusing, and that cannot help the science divulgation.
    I dont agree with Colugo’s ‘orthoape’ cause I speak spanish, and the spanish translation ‘ortosimio’ doesn’t sounds well at all. But more important, I think Filler wouldn’t agree in taking that name cause it refers to the ‘apes’ and if I understood something, that’s just what we don’t want, cause apes descended from those ‘AKA modern (apes), eu- and metabipeds, advanced hominoids’. I think it’s better to refer to humans, just dont use ‘human’. It could be, for example just ‘homids’ (spanish: ‘hómido’, same rooth, different descinence)

  44. What I really enjoy about Filler’s recent work is not that I’m necessarily won over by his arguments but rather the challenging nature of the ideas. Morotopithecus may or may not have been our ancestor (though I’m certainly swayed to notion that it was a habitual biped) but what I find puzzling is the resistance to the notion that we may have evolved from a line of apes which had been upright for 20 million years.

    As the post-cranial fossil evidence from beyond 4 million years is sketchy at best there is no reason yet to fight off Filler’s scenarios. So what if they were upright all along? Are we trying to discover our true ancestry or just attempting to make sure what we find adheres to long standing ideas about our ancestors?

    When, and if, the definitive fossils from the divergence of chimps and apes are found they’ll speak for themselves. No need to get up in arms and take sides over an issue which simply is not clear at this point.

  45. where does human intelligent comes from. why is it so miraculous.

    How did a bunch of cells (brain) capable to understand evolution (million years of learning process at molecular level) in a shorter time?.

    Or is it not to ‘understanding’, is it more to ‘memorising’?

  46. Read the book and the papers posted on the site. It is definately a positive step in understanding our ancestry. Dr. Filler, excellent work. Now if eveyone can overcome their Pithecophobia they will recognize that it is the most likely sequence of events possible. But I do agree that Human in the title is misleading. How about Humanoid?

  47. “But I do agree that Human in the title is misleading. How about Humanoid?”

    In fact, all the apes are already humanoids. Hominoidea (the clade containing apes and humans) means “humanoid”.

  48. Dr. Filler says he uses the adjective “human” to represent our upright body plan because (if I understand him correctly) the creatures that share it have a commonality of life experience that makes them all similar in some important way that is worth emphasizing. I can’t decide whether I buy this or not — my imagination is not what it might be. Perhaps someone who has a clear vision of “what it is like to be human” (human in Dr. Filler’s sense) would be good enough to explain it, at paragraph length, and in concrete terms.

  49. There’s more than a paragraph written to explain this – you would need to read “The Upright Ape” to get the full explanation.

    It’s easy to state (at one extreme) that only if a hominoid is a (your race) modern Homo sapiens sapiens with full language skills and technological competence – that this is definitely a human. The more challenging question is to ask how we define the dividing line between ape and human at the other end of the evolutionary spectrum.

    The natural assumption is that the distinction is going to be in the shared possession of our eloquent minds. However, there really isn’t anyone arguing that australopithecines should be called “apes.” This is so because it had been accepted for many years that australopithecines lived after the chimp/human split. It was assumed that before that split we had quadrupedal knuckle walking “animals” and after the split we had a distinctly human lineage, so it wasn’t too risky to call australopithecines “early humans” or “proto humans” rather than “apes that are distinctly related to humans” or some other terminology.

    However, it has been clear for many decades that the brain of an australopithecine is not too much different from the brain of a chimpanzee. They are on our side of the dividing line because they are upright bipeds. In the book, I trace out the history of these ideas and the role of Washburn and others in providing the “creation myth” that Art Weiss and El Paleo Freak find threatened.

    I’m making three points. Firstly (as the Ardipithecus finds have now confirmed) the common ancestor of chimps and humans probably looked more like a human than a chimp. The common ancestor was an upright biped and not a knuckle walker.

    Secondly, aside from the intellectual differences a creature like Ardipithecus that is a bipedal hominiform hominoid shares anatomical and adaptive elements with “post-split” hominids (like australopithecus, Homo habilis, etc. This is not an argument that dinosaurs and penguins are human. This is about closely related hominiform bipeds. This is important because it establishes that our body form (hands free, upright, bipedal) is primitive within the hominoids – possibly representing a continuous stream of species back to Morotopithecus 21.6 million years ago. We inherited a very ancient and well adapted body form, but benefited from brain enlargement and other refinements.

    Thirdly, it has a systematic or cladistic meaning. Either we are called apes (a description of a monophyletic clade defined by our molar cusp pattern) or we have a long hominiform (or “human”) lineage from which various other lineages departed to become orangutanian apes, gorilliform apes or chimpanzee apes. The nomenclature is a mess when you try to apply Hennigian cladistic rules.

    For many people there is a scientific “creation myth” (humans occur after the chimp-human split when an animal rose up on it feet so it could develop it hands and brain). For others there is a theistic distinction between animal and human wherein only the humans have a soul and a special relationship with your chosen type of god. If you’re in the theistic group, then all of the details above are wholly irrelevant to you I’m sure.

    The bottom line is that the common ancestor of chimps and humans was more a human than a chimp from the point of view of body plan and the wide adaptive suite that goes with this – and therefore the question posed by the title of the original post. It is important to ask this question and struggle with it if we are ever going to truly understand the sequence of events that have made us what we are now.

    Trust me, I can understand how you can come up with hundreds of incompletely thought out objections and attacks (humorous, dry, ironic or outraged), but you might start by reading the book so you don’t tread through ground that you don’t need to in making a plausible case.

    1. First of all, I say to Dr. Filler “Shame on you!” — I asked an honest question and received a nasty answer.

      It was Dr. Filler, and not I, who asserted that the upright body plan renders all hominids who have it similar in their life experience, thus justifying the term “human” for all of them. It was this assertion alone that I questioned. Dr. Filler had made a statement about the suitability of his terminology and it was this statement about terminology that I found unsupported by evidence. In this context I made and make no comment relating to cladistics or to the facts of anthopology.

      My own personal observation, among members of my own species, is that life experiences in natural situations depend very much upon one’s size. My cousin, 76″ high, can call upon physical resources which I at 65″ lack, and I in turn have physical resources unavailable to a friend of mine at 50″. Some of the extinct hominid species were even smaller than that. Imagining what it feels like to be living in the wild in Africa, I can certainly feel a commonality — a common “humanity”, if you like — with extinct hominids of approximately my size, who might have have shared my assessment as to which carnivores in the environment were dangerous enough to be threatening, and which were not. However, I expect that a fifty pound hominid would face survival problems that I have never dreamed of and that would entirely consume his life. In short, if one wants to extend the notion of humanity beyond our own species to embrace a commonality of experience, then the size of the individuals is relevent.

      Finally, I wish to record my distain for Dr. Filler’s method of argumentation. He was asked for one paragraph supporting an unsupported assertion he made in his posting. Declining to do so, he replied (using several paragraphs) “read my book” or words to that effect. If someone is unwilling to give an outline of his thoughts, the assumption among serious people must be that his thoughts are insufficiently clear to be taken seriously.

      1. Art Wiess,

        Firstly, if you can’t stand the heat, you should stay out of the blogosphere. So no complaints that people aren’t being nice enough to you.

        Secondly, – shame on you – your question is meant to be irritating and you know it. For instance: “I don’t believe in MRI (magnetic resonance imaging) – can you explain MRI in one paragraph? If not then I am not convinced”

        Of course this a version of the Shamai/Hillel apocryphal tail. A man comes to the great scholar Shamai and says – I will convert to Judaism if you can explain the entire torah to me while I stand on one foot. Shamai is rightfully insulted and chases the man away with a broom. The same man goes to Hillel with the same question. Hillel smiles and replies – “do unto others as you would have others do unto you…the rest is merely commentary.”

        I guess I could why you think a major change in the definition of humanity should be fully explainable to a doubter in one paragraph. This is particularly the case because I do have a single paragraph in the blog that clearly states the position “What defines a human…” I then use the rest of the blog and the book and other articles to explain what the paragraph says. In the Hillel example I give above, the man has to be satisfied with a one liner in place of all the centuries of commentary and learning – for which he obviously has considerable disdain.

        The bottom line – you’re argument that it must be false if Dr. Filler can’t convince Art Weiss in one paragraph might work for Paris Hilton convincing you that she’s an internet celebrity, but it doesn’t really work for a subject like this in academically oriented forum.

  50. “In the book, I trace out the history of these ideas and the role of Washburn and others in providing the “creation myth” that Art Weiss and El Paleo Freak find threatened.”

    Sorry, I dont think I find anything “threatened” here, not to mention a “creation myth”. Please don’t assume my opinions or feelings.

    “(as the Ardipithecus finds have now confirmed) the common ancestor of chimps and humans probably looked more like a human than a chimp”

    Well, Ardi looked more like humans in some aspects, and more like chimps in others (for example: short legs and long arms, opposable big toe, skull shape, brain… )

    “it has a systematic or cladistic meaning. Either we are called apes (a description of a monophyletic clade defined by our molar cusp pattern)”

    “Apes” is not a cladistic description nor a taxonomic term.

    (…)”but you might start by reading the book ”

    It’s not very elegant to make controversial claims on the Internet and then responding “read my book”. We are commenting a blog article, not your book. Maybe if you respond in a more convincing way we end buying and reading your book.

    1. El Paleo Freak,

      I’ve seen your various comments on this. I did write a blog of reasonable length. Books are not an archaic and worthless communication form. The suggestion that any concept that requires a book length exposition to fully explain is a bad and worthless idea is embarrassing – is that why you don’t use your real name to sign your comments?

      For instance, in the book, I spend an entire chapter investigating the history and relevant controversies on Hennigian cladistics. I show Ernst Mayr’s attacks on them. I explain how common names are used since many Hennigians reject the latin binomial system of Linnaeus. This is why the term apes is as relevant as the words dinosaur, bird or lizard. They say we can’t distinguish birds from dinosaurs because both are monophyletically archosaurs, but the discussion pertains to the words “bird” and “dinosaur” for a variety of reasons, just as it pertains to ape and human. Like Art Weiss you want it explained while you stand on one foot.

      You have already stated that it is “ruining this site” even to allow me write the blog. So the idea that I then write one more paragraph and you change your mind on all aspects of the concept is not very believable. Given your starting position (suppress this irreligious comment of Filler) I’m not surprised you are afraid to read the book.

      When I write a summary of Harvard PhD Thesis and publish a book with a foreword by David Pilbeam (then Dean of Harvard) and you say “ban it” it sure sounds like you are alarmed at an attack on your creation myth. It certainly doesn’t sound like you’re responding to a discussion of data to assess a scientific issue. Why not just go on to suggest not only banning me from blogging but also burning the book. The reason why people burn books is that they have a power to convey an argument – even a convincing argument that a person like yourself does not want to hear and does not want others to hear.

  51. Dr. Filler,
    Of course terms like “ape” or “lizard” are used by scientists, and relevant in may ways. But, sorry, ape is not “a description” of a “monophyletic clade”, as you said. That’s false.

    I find your stuff about a “creation myth” a very poor and dishonest way of argumentation.

    Insinuating people are alarmed, afraid to read your book, wanting you to be banned, or wanting your book to be burned, are other classical symptoms of crankism.
    I’m very sorry (because it would be exciting) but:

    -Nobody here seems to be threatened, alarmed, or afraid of your ideas.

    -Nobody is going to burn your book.


  52. El Paleo Freak,

    The important issue is the substance. The argument is about the impact of homeotic genetics on the pace and components of morphological change. Major changes in morphology can occur abruptly. The prime example is the 180 degree flip of the body plan at the origin point of the vertebrates. This occurred because of a single change in a single morphological gene that determines the main axis readout early in embryonic morphogenesis. The flip did not happen a few degrees per year under selective adaptation pressure. Thus vertebrates originated from invertebrates more or less in a single generation.

    I have primarily argued that there is a line of evidence for a similar event in early hominoid history following the molar cusp change that is the fossil marker for the monophyletic clade of the hominoids. I distinguish proconsuliform apes from hominiform apes. Among the hominiforms, the species appear to be tailless and have many body form changes (you know where to look to see each of the changes discussed in detail). I believe that it is fair to say that the proposed abrupt homeotic origin of habuitual upright posture that followed from the axial transformation constitutes a critical origin point for a type of mammal we distinguish as human.

    There is a cladistic argument that we have just individual creatures of no difference in interest from one to the next algae, slime mold, dog, human etc. Each should have a phylo code and it is unscientific to consider Homo habilis (or Homo sapiens) as any more worthy of study than for instance a particular dandelion. Another point of view is that there are certain character assemblages that are biologically interesting from an objective point of view. Anthropologists are interested in what makes a human distinct from other primates or other mammals. This question is aided by continuing reassessment of what distinguishes the human from the closely related, but non-human hominoid.

    As for using high quality arguments, here is the quote from the El Paleo Freak about this post:

    “That’s how cranks start their marvelous and “revolutionary” claims against the Establishment. Pity for Anthoropology.net. This kind of fringe science is ruining the site :-(”

    So I guess that represents what you consider the high road in academic discussion. Once you have called a serious scientist a “crank” engaged in “fringe science” in a public forum you have given up the opportunity to sound convincing when you later spout a lot of righteous indignation about argument quality and people making assumption about you.

  53. El Paleo Freak,

    The next step here is to consider the impact of the mix of features in Ardipithecus that you refer to – some being more similar to chimps, some being more similar to humans. The point I make is that the features more similar to humans appear to be the primitive features. That is, the “human” like features appear to come from Ardipithecus ancestors while the “chimp” features are derived and advanced as the chimp evolves away from a human-like ancestor.

    I predicted that as we found more fossils, the evidence from the periphery would match the evidence from the spine. This was born out by Kivell and Schmitt (PNAS 2009) who found evidence of independent origin of knuckle walking in chimps and gorillas (see my blog on this: http://researchblogging.org/blogger/home/id/1142/post_length/full) (Diagonal postures and the descent from human to ape) and by the findings on Ardipithecus from the Lovejoy group.

    As for your repeated assertion that this is “crank” science – fortunately, I can prove you are wrong and foolish on this as well as being unable to admit/withdraw or sign your real name to it. If you search on Google Scholar for AG Filler you can check the citations yourself (aside from my work in diffusion tensor imaging and neurography collectively with hundreds of citations) – my recent papers on homeotics and the definition of humanity are cited in Nature (Luo et al Nature 2007), Journal of Anatomy (Crompton et al 2008), Evolution & Development (Buccholtz et al Evol. Dev. 2009), (Young et al Evol Dev 2009), Journal of Experimental Biology (Vereecke et al J. Exp Biol 2008). Earlier work I’ve done on this has been cited in Journal of Paleontology (Sanchez-Villagra et al J.Paleo 2000), American Journal of Anthropology (Johnson et al AJPA 1998), (Shapiro et al AJPA 1995) etc.

    I presented a talk entitled “A Humanian Model of human evolution: Evidence that habitual upright bipedality is a synapomorphy that defines a hominiform clade of hominoids including humans
    and all extant apes” at the Annual Meeting of the American Association for Physical Anthropology in April of 2008 that was attended in a packed room by over 200 physical anthropologists and received a standing ovation – which is quite unusual for academic talks.

    You can also read my invited blog on the Oxford University Press website on this subject: (Redefining the word “Human”)

    So if I’m regularly cited in numerous premier journals in the field, accepted enthusiastically when I speak at professional meetings, and continue to get invitations for serious blog sites like Oxford University Press — but a cowardly anonymous El Paleo Freak says I’m a “crank scientist” because he doesn’t agree with the conclusions – then I think El Paleo Freak is a good anthropological example of a person bound into his/her own creation myth that considers any non-believers in his own myths to be a fools.

  54. “Thus vertebrates originated from invertebrates more or less in a single generation”

    Etc. I see. You are trying to support controversial claims by making more controversial claims.

    “The point I make is that the features more similar to humans appear to be the primitive features”

    The primitive features? The? So the other features, the ones that are more similar to the chimp… are they not primitive features? What is the ape-like skull of ardi, for example? A convergence?

    “So I guess that represents what you consider the high road in academic discussion”

    You guess wrong -as usual. I have never pretended anything of that kind.

    “I can prove you are wrong and foolish on this as well as being unable to admit/withdraw or sign your real name to it”

    No! Perhaps you can prove I am wrong (lets see…), but you can’t prove I am unable to use my real name here. If I choose to use just a nickname (like hundreds of thousands of Internet users), personal “unability” can be a possible reason, though a very improbable one :o)
    My congratulations for all those citations and ovations! But I still think that claiming the first human was 21-million-year macromutant is a crankish claim. Sorry! There is not incompatibility between crankism and some academic recognition. The combination is not uncommon. You probably know a famous scientist that is gorged herself of citations and ovations. But… she continues claiming that new species arose by the mixing of entirely different organisms (of course she uses a particular meaning of “species”), or that beneficial mutations can’t exist…

    “a cowardly anonymous El Paleo Freak says (…)”

    This can be read as a dumb attempt to provoke. It could weaken your argumentation a bit more.

    1. El Paleo Freak,

      There is no question that a mutation took place that had a large morphogenetic effect. This is the repositioning of the dorso-ventral body plane from its standard vertebrate/mammalian position ventral to the nerve cord to a new position dorsal to the nerve cord in the lumbar region. I have also shown that this “septo-neural transposition” appears to be the mechanical basis in the spine for upright posture in the hominiform hominoids.

      We then return to the question of what is the defining factor for calling a hominiform hominoid “human” as opposed to “ape.” This is a subjective issue about the importance and meaning of certain characters.

      Another way of considering the question is to ask what you would call a chimpanzee individual who was born with an atypically large brain and was capable of full symbolic thought (as in Terrence Deacon’s “The Symbolic Species”), eloquent speech and full social graces. I think it would still be a smart eloquent ape.

      An individual of Australopithecus afarensis with the intellect and behavioral repertoire of a modern chimp would still be called “human” by most anthropologists.

      So it comes down to asking what feature or features a paleontologist needs to see in a fossil from 6 to 8 million years ago to assign it to human or ape.

      You try to imply that my argument is that a fully evolved Homo sapiens sapiens individual was born by “macro” mutation 21 million years ago – and I’m sure you understand that is not at all what I’m describing.

      The morphological transformation in the body axis is placed in context among mammals in my PLOS One paper on homeotic evolution in the mammals in which I trace numerous axial character states across 250 species and 250 million years. This is also covered in my Axial Character Seriation book. This transformation is the reason why the Moroto lumbar vertebra from 21.6 million years ago looks almost indistinguishable from a modern human vertebra and also why it looks very different from the vertebrae of cercopithecoids or proconsuliform hominoids. The human form of lumbar vertebra is what has been found in all five of the fossil hominoid species that have been discovered so far from before the chimp-human split.

      I know that the idea of a “macro-mutant” strikes hard at the ego of a person who describes themselves as a “Freak” – but fear not, although the morphological change is large, the amount of DNA changed is probably very small. That is what is so interesting about major homeotic mutants. There are hundreds if not thousands of examples of this in the literature –not just the vertebrate origin example as you seem to suggest.

      As for the “crank” issue – I don’t question the fact that this is your belief. I have also now observed repeatedly that you have fixed ideas unresponsive to evidence or argument so I don’t expect to change your mind. I was just making the point that numerous very respected experts in paleontology and anthropology may not agree but take the information as a compelling interpretation of the data available.

      I did wonder if aside from spouting insults and attacks from behind a screen of anonymity you are unable/unwilling to shed – do you have any specific arguable ideas on this subject? You know —- can you be constructive instead of destructive? Specifically – what are the characters you think a paleontologist should look for to know if a fossil hominiform hominoid from say 4 to 12 million years ago is to be considered ape or human or are there are no conceivable features that seem relevant to you?

  55. “This occurred because of a single change in a single morphological gene that determines the main axis readout early in embryonic morphogenesis. The flip did not happen a few degrees per year under selective adaptation pressure. Thus vertebrates originated from invertebrates more or less in a single generation”.

    Not likely. If the relevant mutation giving rise to a new species occurred in a single individual (as seems most probable) how on earth would it reproduce to be able to sustain the new species? Asexually?

    1. El Paleo Freak

      At this rate, the total blog comment set will be longer than the book. Your question on speciation shows you don’t have much formal background in biology or evolution. This sort of issue is something I used to teach undergraduates in various courses over the five years I taught at Harvard back in the early 80’s. Perhaps you never went to college.

      The chapter on speciation in Upright Ape might be helpful for you. Maybe you don’t have a job and can’t afford to buy and read books so you have to get all your information from blogs. I don’t think you need to buy the book, it’s available in many libraries. There are also many other books on this subject in libraries.

      In any case, you are confusing speciation with genetic change/mutation. Speciation is reproductive isolation of two populations. It is true that classical (e.g. 1940’s and 1950’s) teaching on Darwinian theory projected that speciation occurred by the gradual accumulation of disparate sets of alleles in two populations with little interbreeding so that eventually the allelic make up would be so different that the two populations could no longer interbreed. This required some sort of geographic barrier to block the flow of alleles before actual speciation took place (one of my professors – Ernst Mayr – was certainly an advocate of that view).

      In the 1970’s a number of workers developed a rather different model – this is what is called chromosomal speciation (see Michael JD White – Modes of Speciation). I step through this in some detail with diagrams in the book. In essence, chromosomes appear as an X because the paired left and right side are joined at the centromere (this is the standard way they are shown, selecting the gametocyte stage after part I of the two step meiosis process). The entire chromosome can undergo centric fission so that one X becomes two V’s (a left and right pair from the top of the X now form one V and a separate left and right pair from the bottom of the X form a second V) – although the vast majority of the genetic material is completely unchanged. An individual with the two V’s is able to mate and produce offspring with an individual still carrying the X – the two V’s of individual A correctly line up on the relevant parts of the X from individual B. No barrier results.

      A second fission occurs in the population. Again it is no harm no foul as no barrier results. However if an individual occurs in which an “upper” V from one of the chromosomes undergoes centric fusion with the “lower” V from the other fission, we get a new type of X. These individuals can interbreed with individual having the four V’s, but they can no longer have offspring with individuals having one of the original X’s. The V’s tend to fuse so the situation of four V’s provides a bridge between two isopatric populations tends to be shortlived. Once additional fusions take place, the bridge closes and you have two reproductively isolated populations. A speciation event has taken place. This is totally independent from the accumulation of changed alleles or any evolutionary change at all. A number of such fission and fusion events have occurred that distinguish the chimpanzee karyotype from the modern human karyotype. There represent the history of various intervening chromosomal speciation events over the past six to eight million years in our lineage.

      Now lets look at the “first vertebrate.” Remember although it is a very large morphologic change, only one base pair needs to be different at a critical point in the dorso-ventral readout gradient gene. This mutation has actually been identified (see the discussion in Upright Ape). So from the point of view of the DNA, the vertebrate and invertebrate siblings can have nearly identical DNA but for a single base pair change. It is true that in more advanced animals, the major shape change might tend to seriously discourage interbreeding or might make it physically impossible. However in the vertebrate/invertebrate situation, the reproductive mechanism of released sperm and eggs did not present any physical barrier to interbreeding. No speciation had occurred yet. The two radically different morphologies existed in the same species with ongoing breeding gradually producing more of both types.

      When major morphogenetic changes occur – the result is usually a non-viable fetus that dies. Occasionally, a major change occurs but the creature is able to survive into reproductive adulthood. Very very occasionally, the change is not overly deleterious to survival. In very very very occasional circumstances it might even be beneficial. However, it probably usually requires extensive subsequent work over generations by adaptive Darwinian processes to improve and optimize the new major change in order for it to become overall beneficial to carriers. In any case, many such changes – even when beneficial – get lost eventually because they constitute a low frequency allele which may or may not persist in a given species.

      What we are concerned with is the homeotic changes that permit survival, do not include a mechanical barrier to interbreeding with other individuals in the species that don’t carry or express the new homeotically altering allele AND which eventually get captured in a small population in a chromosomal speciation event. Then you have a new species with a high rate of occurrence of the new morphology. If the allele goes to fixation, it becomes characteristic of the new small founder population. In this case the new daughter species looks very different from the parent species.

      Hope that explains it. If not – you know where I recommend you look for a more detailed explanation.

  56. “Your question on speciation shows you don’t have much formal background in biology or evolution.”

    Beep! Error again! I haven’t yet formulated any question on speciation. And I have no problem at all with chromosomal speciation and other basic, non controversial issues you don’t need to explain. You could have saved yourself all that effort.

    “Maybe you don’t have a job and can’t afford to buy and read books”

    Yes, Dr. Filler! That’s the reason I want to burn your book: I hate books because I am poor and I can’t afford them. :’o)

  57. “In any case, you are confusing speciation with genetic change/mutation”.

    What’s the difference, apart from the fact that genetic change/mutation doesn’t always lead to speciation. But speciation can only arise through genetic change/mutation.

    “reproductive isolation of two populations”

    Reproductive isolation would usually lead to subspeciation before it gave rise to speciation.

    “What we are concerned with is the homeotic changes that permit survival, do not include a mechanical barrier to interbreeding with other individuals in the species that don’t carry or express the new homeotically altering allele AND which eventually get captured in a small population in a chromosomal speciation event”.

    Isn’t that just the same thing as, and more easily explained as, being a recessive gene. An advantageous recessive gene can only be expressed after being ‘captured in a small population in a chromosomal speciation event’: inbreeding. If the recessive has become widely spread through a population the phenotype change could be rapid. By using recessive genes to explain the process you don’t have to postulate ‘In very very very occasional circumstances it might even be beneficial’. Disadvantageous recessive genes are held in check by the individual’s lack of survival. With the expansion of a new recessive gene combination you could well ‘have a new species with a high rate of occurrence of the new morphology. If the allele goes to fixation, it becomes characteristic of the new small founder population. In this case the new daughter species looks very different from the parent species’.

  58. terryt,

    If you go back through what I’m saying about chromosomal speciation – in fact you can have speciation with no mutation. It is an entirely different phenomenon associated wht the centric fission and fusion of chromosomes but is not directly related to sequence change in the DNA per se.

    The point for the scenario here is that they are decoupled. El Paleo Freak objected to sudden morphogenetic change by asserting you would then have to have asexual reproduction. I am just pointing out that with homeotic genes, you can have a great deal of morphologic change with no speciation. In this way, the new morph can begin to appear in many individuals before (quite independently) a speciation event occurs to capture the change.

  59. “El Paleo Freak objected to sudden morphogenetic change by asserting you would then have to have asexual reproduction”.

    I said that. And I still say you don’t get sudden speciation because the new species has to start with a population of reasonable size.

    “It is an entirely different phenomenon associated wht the centric fission and fusion of chromosomes”

    You pointed out that individuals with ‘centric fission and fusion of chromosomes’ can still interbreed with members of their species who don’t have it. So you do not get a sudden change of species even under the scenario you propose.

    “When major morphogenetic changes occur … In very very very occasional circumstances it might even be beneficial”.

    But the individual with that beneficial mutation still has to find someone else with that same mutation to have offspring with. An unlikely event, unless the mutation has already spread through the population, behaving in a manner similar to a recessive gene. And ultimately giving the same result.

    1. Terryt,

      I think you and I are in agreement on all this. A homeotic mutation occurs. This may cause a large of amount of morphologic change, but is just another allele. If it confers an advantage, it’s frequency will increase. A speciation event may occur leading to a daughter species with the allele or it may spread through the population with no speciation event.

      For some reason, El Paleo Freak asserted that if there was a large morphologic change (such as the invertebrate to vertebrate change – or even the septo-neural transposition in early hominiform hominoids) then you would need asexual reproduction because it would lead to a species of one individual. I am making the point that the morphological change is entirely independent of speciation. We don’t even need habitat change for geographic separation. This is all not controversial.

    1. El Paleo Freak, Terryt,

      The comment is from TerryT:
      “Not likely. If the relevant mutation giving rise to a new species occurred in a single individual (as seems most probable) how on earth would it reproduce to be able to sustain the new species? Asexually?” (apologies to El Paleo Freak on the attribution)

      Obviously, any initial mutation will always occur in a single individual. If the change is the 180 degree flip (and this is not my idea, it is a fact – see De Robertis & Sasai (1996) Nature 380: 37-40) then once it has occurred you have the new kind of animal – even before it separates off as a species.

      For instance, if finches are yellow, and then one bird is born that is green, then that individual could be the first green finch. The allele could spread and eventually become the most common or the fixed allele in a new species whose individual are always green. At that point you would have a yellow finch species and a green finch species. However, the first green finch would be an individual offspring of a yellow finch. The first vertebrate is one offspring of an invertebrate that has undergone the 180 degree flip during its embryogenesis (even though there is no speciation yet).

      The first hominiform hominoid of human aspect is the one offspring 21.6 million years ago that has the septo-neural transposition and is thereby primarily an upright biped. In homeotic change, single base pair changes can result in large morphologic changes.

      A similar event is involved in the origin of the Bilateria. Prior to this point, we had non-symmetric or radially symmetric creatures (worms etc). Then a right left mirror occurred (in the initial embryonic read out gradient in the Hox genes) resulting in the first Bilaterian. This would be as distinct from the unlikely scenario of a left half evolving gradually under Darwinian selection over many millions of years from creatures that initially had only a right side with a partial left side sticking out. The Bilateria (insects, crustaceans, humans) emerged abruptly in a single generation as a single mutation. This would be as distinct from the subsequent speciation event that captures the change in a distinct lineage. Starfishes have multiple morphogenetic mirrors.

      This is why it does not take 15 million years of gradual evolution to change the proconsuliform or cercopithecoid type of lumbar vertebra into the radically different form of the modern human lumbar vertebra. It is seen 21.6 million years ago – very soon after the emergence of the hominoids from the cercopithecoids and then it stays fairly unchanged on into modern times.

      Hence the proposal. The feature that really distinguishes human from ape is not intellect but habitual primary upright bipedal posture (consider the brilliant conversational chimpanzee mentioned above that is still a very smart chimp and not a human) – a matter of body plan. If we can find a lumbar vertebra fossil and see that a given hominiform hominoid has the homeotic mutation that underlies it, then we have a feature you can see in a fossil that reveal the basis of upright posture, hence the basis of the “human” type of animal. This becomes a consistent “primitive” lineage. Other lineages like gorillas, orangs and chimpanzee independently branch off from an upright bipedal ancestor to specialize as diagonograde knuckle walkers or fist walkers. For this reason, we have a creature with the typically human body form (upright primary biped) as the ancestor for various ape lineages as well as being ancestral to our own lineage after the chimpanzee lineage splits off. Our ancestors before the chimp emergence look fairly similar to our ancestors after the chimp emergence with regard to habitual upright bipedal posture.

  60. “Other lineages like gorillas, orangs and chimpanzee independently branch off from an upright bipedal ancestor”

    I’m quite prepared to accept that. Where I have a problem is with your arguments in favour of instantaneous speciation.

    “This is why it does not take 15 million years of gradual evolution to change the proconsuliform or cercopithecoid type of lumbar vertebra into the radically different form of the modern human lumbar vertebra”.

    I think everyone these days agrees that evolution often is extremely rapid. But one generation?

    “The Bilateria (insects, crustaceans, humans) emerged abruptly in a single generation as a single mutation”.

    What evidence do you have for that? I doubt it.

    “At that point you would have a yellow finch species and a green finch species”.

    No. At most you might have two subspecies, or a polymorphic single species. They’d still be capable of forming fertile hybrids unless they remained isolated long enough for incompatible genes to evolve in one or other population.

    “The first hominiform hominoid of human aspect is the one offspring 21.6 million years ago that has the septo-neural transposition and is thereby primarily an upright biped”.

    Leaving aside arguments over the 21.6 million, the individual with that ‘first hominiform hominoid of human aspect’ cannot be a new ‘species’ if he or she can form fertile offspring with individuals of the old species. Either that, or he or she is a species consisting of just one individual. It’s more likely that the species is polymorphic and the new mutation came to dominate over time.

    The term ‘gene’ was used long before we knew how they were carried on the chromosomes. The examples of gross chromosome change you have mentioned are simply one of the ways new genes form. You still need two copies of the change before it’s expressed. So you’re talking about recessive genes.

    Further, you’re claiming that once the double recessive appears it is immediately a new species, by definition, unable to breed with the old. So, as well as the ‘very very very occasional circumstances’ in which a beneficial gene evolves you’re also arguing for the even more unlikely scenario that more than one individul of this new species will appear at the same time. I’ll grant some of the individual’s brothers or sisters could also be double recessive, but this would provide a very limited gene pool as the basis for the long-term survival of the new species.

    On the other hand a single isolated population of a species could change quite rapidly with the spread of an advantageous recessive gene. Those with the double recessive would still be able to breed with single recessives, and even double dominants. But the double recessive form would replace the previous dominant gene by selection. And the gene could spread rapidly once a double recessive individual appeared if the gene had already spread through the population’s geographic range as a single recessive.

    So, ultimately we arrive back at your professor’s comment, ‘This required some sort of geographic barrier to block the flow of alleles before actual speciation took place’. For one species to develop into two we need separation, either geographic or tribal (ecological?).

    1. Terryt

      Stop. You are totally misreading what I write. Again and again.

      I am not concerned at all with “sudden speciation.” That has no part in my position and I don’t claim it. I don’t state sudden speciation.

      You are continuing to confuse mutation with speciation.

      Please carefully and slowly re-read my comments. I very carefully said that you would have a first green finch when a green sibling was born. That is not the same as a speciation event. It is just a mutation. The argument is very clear for the 180 degree flip or for the bilaterian mirroring. These are single gene mutations that cause large morphological changes creating new body plans, but they do not form new species. Speciation is entirely a different subject. In my recent comments I have slowly traced this out. Your argument about sudden speciation is irrelevant to my comments and it is irrelevant to the question of what features constitute a human.

      Speciation is about reproductive isolation that leads to different sets of alleles in the separated populations. Some types of speciation are related to gradual accumulation of allele changes. I have just tried to point out that this sort of body plan origination can involve a sudden morphological change – remember, all mutations are “sudden” in that they occur and appear in a first individual and then spread in a population. The initial appearance of a new single gene character is always sudden. It is a chemical reaction on one base in a DNA chain of a gamete. You are confusing a variety of different biological processes that occur at various levels.

      With regards to mutations, there is a reasonable argument that the vertebral change represents an accumulation of hundreds of small adaptive mutations that gradually repositioned and restructured the vertebra over 500 generations. However, there is also a reasonable argument that this type of change could be a single homeotic mutant. Either way, I believe it happened by 21.6 million years ago and that it defines a new type of hominoid subgroup that then is introduced into a new adaptive zone by the emergence of vertebrally based habitual upright posture and bipedalism.

      1. Dr. Filler:
        I apologize for coming to this issue rather late. I’ve been occupied by more pressing matters for the past few years and have turned to the arrival of Homo sapiens only in the past two or three weeks.

        You said “This is a question of definitions…” And so it is. But I can never agree that the redefinition of “human” should abandon the role of intellect and have solely “a new morphogenetic basis” involving “a dramatic restructuring of the lumbar vertebra that inverts the mechanics of the spine and undoubtedly underlies our upright bipedal posture.” Relying solely on “a new morphogenetic basis” is too simplistic. Being specifically human is much, much more complicated. It’s true that we’re members of a group that has this “dramatic restructuring of the lumbar vertebra”, but as is true with all good definitions, we have other characteristics that separate us from other members of the group. Chief among those other characteristics is the processes that engage our magnificent brain. To be specifically human is to have a body plan that has “a dramatic restructuring of the lumbar vertebra” and also to be able to gaze upon the far reaches of the Universe. Stated mathematically, to be called human, it’s necessary, but not sufficient, that an animal have a body plan with “a dramatic restructuring of the lumbar vertebra”. There are, after all, differences between humans and all our ancestors, and those differences are part of the definition of human. Of course, those differences can not be seen in old bones. Why should they be? It’s not necessary that some ancestor be us. It’s only necessary to say whether or not some old bones lead to us; they don’t have to be us, and to demand that they be us is absurd.

        That “terms like: ‘proto-human,’ ‘early human,’ ‘ancestral human,’ ‘hominine,’ or ‘hominid’ ” “have [allegedly] increasingly been rendered unusable” because “their usage is [currently] in constant flux” is hardly sufficient justification to ignore the characteristics that separate properly defined humans from others in the “new morphogenetic basis” group, and to simply (and arbitrarily) reject those characteristics (such as the processes of our brain) is unreasonable. A video on the National Geographic Web site that your Oxford blog references describes “a recent study showing that chimpanzees consistently outperform human college students on a complex computer based [sic] eidetic memory task [that] shows that the [last] common ancestor’s [LCA’s] intellect was at least respectable” doesn’t necessarily support that conclusion at all. The experiment described in that video strikes at the heart of the issues of the measure of our LCA’s intellect and of the roll of intellect in the definition of “human,” and you use it to justify your claim “that we are unavoidably forced to abandon articulate language and superior intellect as requirements for our critical definition of a human.” So lets look at the experiment.

        The National Geographic video describes a Japanese experiment in which a video monitor displays the digits from one through nine in a random pattern. The display is probably presented only briefly, but the National Geographic video doesn’t tell us the length of time. The subject is required to touch the numbers on the screen, in order, from one through nine. When the first number is touched, the rest of the numbers change to merely white squares, forcing the subject to remember the numbers’ locations in the pattern in order to touch the squares in the proper order. The National Geographic report describes the experiment as designed to test short term memory. You ‘ve described the experiment as a test of eidetic memory, or photographic memory, which is probably more accurate than National Geographic’s description of “short term memory”, which may or may not be eidetic. Chimpanzees routinely performed much better on the tests than college students. That difference is probably more indicative of the difference between chimpanzees and college students in the way their short term memory works than a test of any component of intellect. As you implied by using the term “eidetic memory”, the short term memory of chimpanzees probably works by taking a snapshot of what the beast sees; the short term memory of college students—distracted as they are with thoughts of coeds, pizza, and beer—doesn’t necessarily work that way, although a few might have such an eidetic memory. The Japanese experiment plays to the strength of chimpanzees’ eidetic memory.

        The performance of chimpanzees in the Japanese tests mirrors the abilities of Kim Peek, who displayed the characteristics known as savant syndrome. Kim could read a very long string of numbers and then recite them back perfectly; he could read a page in a book and quote it word for word—he just didn’t know what the words meant because he happened to be at the low end of the probability distribution describing human intelligence. Chimpanzees understand even less about the meaning of the tests they take; at least Kim understood that the words he could recite had meaning beyond that which he could comprehend whereas the chimpanzees probably weren’t even aware that the test they took even had any meaning. The tests were simply an exercise they performed, probably to merely get food. Extraordinary feats of recall typical of an eidetic memory don’t imply understanding, and understanding, not recall, is the mark of intellect. The more complex and abstract the concepts one understands, the greater one’s intellect. The Japanese experiment is an interesting demonstration that chimpanzees can display a modest ability to count and can recall a nine-element pattern. It also demonstrates an eidetic memory has a bit of an advantage of when it comes to dealing with visual patterns. But the experiment tells us nothing about intellect.

        After noting in your Oxford blog that chimpanzees performed better than college students in the Japanese experiment, you proceed to equate eidetic memory to intellect by then claiming “that we are unavoidably forced to abandon articulate language and superior intellect as requirements for our critical definition of a human” and focus “upon the anatomy and genetics of the spine”. However, short term memory, especially the photographic kind, is only an insignificant part of intellect. The overwhelmingly major part of intellect is what you do with the information short term memory has absorbed. When chimpanzees design the tests, or virtually anything else in the room, it would be time to consider that a chimp has some semblance of “intellect”. Your argument justifying your claim “that we are unavoidably forced to abandon articulate language and superior intellect as requirements for our critical definition of a human” is seriously deficient.

        Your data, while important contributions to the body of human knowledge, are irrelevant to the issue of the definition of human. The data set leads us to the understanding that there exists an animal group that has “a dramatic restructuring of the lumbar vertebra”, an animal group of which humans are a member, but the data do not support an extension to the specific conclusion that all members of this group should therefore be called human. The data do not lead us there. A set is not defined solely by a subset. The extensive technical discussions on the lumbar transverse process (LTP), though educational, only obfuscate the central issue: is it sufficient that a hominid be primarily bipedal to be considered specifically human (as opposed to merely a member of the human’s evolutionary line), or is the ability to design the Japanese test or understand the fusion inside stars a vital part of the definition of “human”? I understand that your position on this matter is a result of your acceptance of “Sherwood Washburn’s premise – that has been the basis of most scientific antrhopological models since the 1950’s – then it is primary bipedalism that distinguishes the human animal from the ape.” We can’t know what the late Dr. Washburn would think of your discovery, but I imagine the “paleo” in him would be pleased that you’ve discovered a characteristic that can easily place old bones in either the human evolutionary line or the line of the apes. But I bet dollars to donuts that the “anthropologist” in him would balk at trying to extend the implications of your discovery to be that the “dramatic restructuring of the lumbar vertebra” is a sufficient measure of what is specifically human.

        In your Oxford blog, you asked, “If you were to see the common ancestor [sic] [of human and ape] would you think ‘human’ or would you think ‘ape?’ ” Because the question has only two options for an answer, we would all be forced to think, “It’s not us, so it’s not human; it must be some sort of an ape, but it’s not like any ape I ever saw.” I can’t speculate on why you worded the question the way you did, but it’s worded too inappropriately to give the responder the opportunity to answer precisely. A more proper wording is “If you were to see the LCA [of human and ape], what would you think it was?” Answering that question by using “terms like: ‘proto-human,’ ‘early human,’ ‘ancestral human,’ ‘hominine,’ or ‘hominid’ ”, or more precisely, pre-human, is not dodging the issue at all. It’s giving a more precise answer to a more proper question.

        It’s certainly true that “terms like: ‘proto-human,’ ‘early human,’ ‘ancestral human,’ ‘hominine,’ or ‘hominid’ ” “have [allegedly] increasingly been rendered unusable” because “their usage is [currently] in constant flux”. All of paleontology, including paleoanthropology, is always in a state of flux, partly because knowledge is increasing faster than we can organize it (or, more precisely, faster than we can agree on what that organization should be). But that’s no justification for simplistically throwing everyone in the same dramatically-restructured-lumbar- vertebra pot and calling us all human. Now that’s dodging the issue of who belongs where in our evolutionary past! I bet that 50 years from now, when you and I are dead, Homo sapiens will be the only human, and our direct ancestors will be called Pre-human 1, Pre-human 2, etc., while all others on our evolutionary tree (or bush as some prefer) will be called Human Cousin 1, Human Cousin 2, etc. Then we’ll be organized.

        Pointing out “that a critical single change [SNP?] in one of our hominoid morphogenes could have” an influence on morphology that’s far more significant that a similar change in other genes is a fine contribution to our body of knowledge. It’s unnecessary to dim the luster of that contribution by championing a dubious redefinition of “human” that is inaccurate because it fails to separate us from others in the hominid group that also have dramatically restructured lumbar vertebra.

  61. So these individuals with ‘single gene mutations that cause large morphological changes creating new body plans’ are quite capable of mating, and producing fertile offspring, with those who don’t?

    “all mutations are ‘sudden’ in that they occur and appear in a first individual and then spread in a population”.

    But they can only spread once a double recessive appears. As you admitted earlier, ‘ AND which eventually get captured in a small population in a chromosomal speciation event’. So we’re back to some level of inbreeding in an isolated population, which leads us back to Ernst Mayer’s position.

    “The initial appearance of a new single gene character is always sudden”.

    Yes. Because by the time a double recessive appears single recessives can be widespread through the population. In the case of a double recessive breeding with a single recessive half the offspring will be double recessive, and off they go, breeding with more single recessives. Therefore you’re correct in saying that fundamentally I agree with you that ,’there is also a reasonable argument that this type of change could be a single homeotic mutant’. However I still have problems in accepting that individuals with ‘large morphological changes creating new body plans’ would be able to successfully breed with those who don’t.

    But I certainly have no problem with your idea that upright walking may be the primitive condition and knuckle-walking is the derived. That would certainly easily explain the connection between the eastern gibbon/orang and the western gorilla/chimp/human groups. We don’t then have to postulate continuous forest between the two regions at some time.

  62. Consider also the linguistic evidence for a human ancestor of apes… chimps and gorillas have a cognitive capacity for language but not for the physical glotto pharyngeal apparatus for speech. Structures lost? perhaps not useful in arboreal environment. I have been suggesting this in my anthro classes since 1981.

  63. Dr Filler this may interest you, this may not. I am a complete layman to all this Anthropology jargon. I am here to tell you that Muslim’s holy book Quran says that a group of disobeying humans were transformed into apes. This may well mean a devolution to apes in the way you trying to explain. Soo keep trying, i believe you will succeed

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