Human hand more primitive than chimp's, study says

July 14, 2015
Scientists in the United States and Spain said the human hand may be more primitive than that of our closest living cousin, the
Scientists in the United States and Spain said the human hand may be more primitive than that of our closest living cousin, the chimpanzee

Strong fists for defending ourselves and opposable thumbs for work as fine as threading a needle—hand specialisation is widely believed to have given humans a major evolutionary advantage.

On Tuesday, scientists in the United States and Spain said the human hand may be more primitive than that of our closest living cousin, the chimpanzee.

In fact, human hands are likely more similar to those of the last we and chimps shared millions of years ago.

"These findings indicate that the structure of the modern human hand is largely primitive in nature, rather than the result of selective pressures in the context of stone tool-making," said a press summary from the journal Nature Communications, which published the study.

In fact, it is the hands of chimps and orangutans that changed most since they split off to form new branches of the hominid —developing longer fingers, compared to the thumb, for swinging on tree branches.

The human hand has a longer thumb relative to the other fingers than that of chimps and other apes—allowing for what scientists call "pad-to-pad" precision grasping, which simply means that our fingertips are able to touch.

There is a widely held assumption among palaeontologists that the last common ancestor (LCA) of humans and apes, an individual whose identity remains uncertain, was a prototype chimp with chimp-like hands.

But a team led by Sergio Almecija of The George Washington University's Center for the Advanced Study of Human Paleobiology, is challenging that.

They analysed the hand-length proportions of humans, as well as living and fossil apes to draw a picture of the evolutionary history, and found the human "thumb-to-digits ratio required little change since the LCA."

"The inevitable implication is that when hominins (the extended human family excluding apes) started producing flaked stone tools in a systematic fashion, probably as early as 3.3 million years ago, their hands were—in terms of overall proportions—pretty much like ours today," Almecija told AFP by email.

"Another important take-home message is that if are largely primitive, the 'relevant' changes promoting the emergence of widespread reliance on stone tool culture were probably neurological" and not manual—meaning it was our brains that allowed for adaptation.

"Any evolutionary model of human hand evolution assuming a chimpanzee-like ancestor will likely be flawed from the beginning," he added.

Explore further: Human ancestor was less-chimp-like than thought: study

More information: Nature Communications, DOI: 10.1038/ncomms8717

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betterexists
1 / 5 (6) Jul 14, 2015
Who said Human hands are primitive? But for Brains....Everything Else is PRIMITIVE in Humans. Take Claws, Take Teeth, Take Bat's Echolocation Feature, Take Birds' Wings, Take Fish....We cannot be comfortable on very high mountains, in deepest areas of the oceans. We do not have the strength of an Elephant nor Agility of Wild cats. We cannot digest wood like termites (they are aided by their gut bacteria, yes). Keep on Adding Features to the list like that. We think that we are formed in the shape of useless ghawwdd, B.S!
gwrede
2 / 5 (4) Jul 14, 2015
The "current assumption" has a few flaws, at least in my understanding.

In my view, too much emphasis is given to the physical dimensions of the hand, while I think what makes or brakes the utility of the hand is between your ears.

A case in point, robots have a hard time gripping an infinite variety of objects, while I can easily do that even with very thick and stiff welder's gloves. Obviously, the designers are looking at the wrong things.

At the same time other species are using limbs as "hands": squirrels, raccoons, kangaroos, otters, rats, mice, beavers, (of course) the apes, many monkeys, ravens, parrots, and even some invertebrates.

What we need, is proper videos of each of these, really looking into how "hands" are used, and how they perform, considering both their geometry and the driving software.

"Half the dexterity with twice the brains" wins, all the time.

////

After all, when we are gone, the next top species is likely to be one of these.
hrfJC
1 / 5 (2) Jul 14, 2015
I agree, functional not primitive is the correct description. We do not need the ability to peel a banana single handedly as I personally have seen a gorilla do in NYC Central Park zoo. And conceivably higher manual dexterity never "evolved ", since not needed by humans not routinely hanging or swinging from tree limbs. Or possibly apes and humans are totally separate species as some believe.
docile
Jul 14, 2015
This comment has been removed by a moderator.
Vietvet
5 / 5 (11) Jul 14, 2015
"A total of 270 modern anthropoids, including humans, all the species of great apes, hylobatids, as well as cercopithecid and platyrrhine monkeys"

" As the emphasis of this work is on the evolution of the human hand, comparisons were made to our closest living relatives (that is, the great apes) at the species level. Hylobatids were pooled at the family level and extant non-hominoid anthropoids at the genus level."

"Our results provide a detailed picture on the evolution of the hand that is drawn from a multiple-regime model-fitting approach that infers the evolutionary scenario that indicates the optimal statistical fit for the observed differences in hand proportions between apes and humans, in terms of both the total amount and direction of shape changes."
http://www.nature...717.html

Having read the paper, they make a convincing case.
Vietvet
5 / 5 (11) Jul 14, 2015
The researchers aren't implying that because the human hand is more primitive than chimps that it is inferior. That does imply the Last Common Ancestor was most likely a ground dweller. Hominids and gorillas stayed on the ground and chimps took to the trees.
Agomemnon
not rated yet Jul 14, 2015
yet another reason for fear the inevitable rise of the planet of the apes.
nevermark
4.9 / 5 (12) Jul 14, 2015
But is it really more primitive - or is it just an impression of scientists, seeking for journalism?


Why are these comment threads always full of baseless negative comments?

This is science people! Its not perfect but its amazing and worth being positive about.

The scientists are using the work "primitive" to mean "early". There is no judgement about better or worse. And implying scientists are dishonest without hard evidence doesn't say anything about scientists. Its just an expression of knee jerk distrust in the poster and inability to appreciate other's work.
michael_frishberg
4.6 / 5 (8) Jul 14, 2015
Everything alive today is equally 'evolved'.

Evolution is about the leftovers, and, since we're all alive right now, we're equally evolved.

Did the shape of the Chimp hand change more drastically than the human hand since we shared an ancestor?

Apparently.

Great White Sharks supposedly are the same as they were millions of years ago, but, they are equally evolved as we are, since they are alive now too.

(And, don't tell me they didn't have to evolve to overcome disease, to be able to absorb a new meat protein from some fish or mammal that was evolving alongside...)
antialias_physorg
5 / 5 (8) Jul 15, 2015
Who said Human hands are primitive?

Raise the monkeys, lower the man.

The scientific 'primitive'. Not the colloquial 'primitive'. We're on a science site. Learn the lingo. Otherwise you're just showing off your lack of education.

'Primitive' in this article does not make any kind of statement about 'better' (or even 'better suited') .

It is an interesting observation that once tool use started the hands (by proportion) stayed pretty much the same. The tool becomes a selection factor. I.e. people born with differing handshapes that cannot use the tools already available are selected against (or conversely: people who could use the already available tools because they had the same/average hand shape had an advantage)
Torbjorn_Larsson_OM
5 / 5 (4) Jul 15, 2015
This work is much more thorough (thanks Vietvet!) than earlier papers that found the same thing.

The same ancestral homology goes for our bipedal walk, as gibbons and monkeys show by easier walking than chimp and gorilla waddles, humans are less specialized than knuckle walkers.

The last 5 years of evolutionary advances shows that humans are not pure pedigree but hardy hybrid (of diverse Archaic Homo), our success pivoting around former failures and an active social and sexual interest in nearby species. (Or not so nearby species, seeing how the Iron Age sheepherder religions all makes a point of scrutinizing their own sex life. =D)

Nitpick: The article means ancestral (vs derived) or stem trait, not the old and (as can be seen in this thread) confusing term "primitive".
docile
Jul 15, 2015
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Torbjorn_Larsson_OM
5 / 5 (5) Jul 15, 2015
@betterexists: "We cannot be comfortable on very high mountains, in deepest areas of the oceans."

But we have evolved special traits that goes into our success:
- A face and brain package that makes us more diverse so recognizable; making us among the most social species.
- A bipedal system that makes us one of the best long distance runners on the planet; a robust immune system of hybrids despite repeated bottlenecks; making us among the most invasive species.
- An ancestral and derived melange of traits; making us among the most versatile species (good at climbing for a non-arboreal species; good at swimming and diving for a non-aquatic species; good at seeing for a non-predatory species, good at color vision for a non-frutivorous species; good at sex and hiding its effects - stealthed and repeated estrous - for a serial monogamous species)

Et cetera.
Torbjorn_Larsson_OM
5 / 5 (6) Jul 15, 2015
@hrfJC: "totally separate species".

Speciation means precisely separation. It is only in recent diverging species that the cross-fertility barriers aren't complete. As an example, Neanderthals were a different species despite our cross-breeding, as have been seen in sperm incompatibility alleles. (E.g. the introgressions - at least three established, one of which later went extinct - were attempted many more times than they succeeded.)

If you mean ancestry, we are still apes. (See Linnaeus pre-evolutionary classification.) In fact, it is easier to observe clades. Humans are archaeans, then eukaryotes, metazoans, bilaterians, chordate worms, craneata skulled vertebrates, teleostomi jawed vertebrates, osteichty fishes, lobe-finned sarcopterygii fishes, synapsid reptiles, mammals, then monkeys, now apes, and a hybrid of at least 3 and perhaps many more Homo apes.

Those are the easy observations. (Well, archaea and hybridization is top notch sequencing work.)
PoppaJ
5 / 5 (1) Jul 15, 2015
The media response to this article makes me want to scream. The Human hand is not Primitive. Its is ancient in design because it is a better design. It has required little change to remain successful. The chimp hand has been insufficient for its use and therefore has resulted in multiple changes for there species to continue to exist. Stupid media.
Steve 200mph Cruiz
4.2 / 5 (5) Jul 15, 2015
Ren,
The gentle gorilla or the clever chimp is a much more amazing specimen than your fat ass hunched over on the computer getting mad at people with college educations.
antigoracle
2.3 / 5 (3) Jul 16, 2015
The gentle gorilla ....

Really?
https://www.youtu...aLo95ufw
antialias_physorg
5 / 5 (5) Jul 16, 2015
So the professors at your college do you explained to you how the information in one physical system can increase over time thanks to random events?

Do you really not understand the difference between global and local?

Entropy can decrease locally (however globally it always increases). The building of more complex (local) systems is always at the expense of vastly more 'chaos' on the global scale. Evolution is not a closed system. It is part of a larger system (the universe...or "reality" if you prefer). It is perfectly fine to have a subsystem grow in complexity in reality. Happens all the time (How do you think you grew up? The sperm/egg you started out as were certainly 'simpler' than the teenager you are now)

You make the same mistake as people who claim that because scientists say "the Earth will warm by 2°C" it must therefore warm everywhere by exactly 2°C.
TheGhostofOtto1923
1 / 5 (3) Jul 16, 2015
Stone tools aren't as useful as spears for combat. The hands that enabled us to swing hand-over-hand through the branches are also uniquely suited for carrying and throwing rocks and spears overhand.

This was the breakout mechanism which enabled us to employ technology to hunt the animals which were hunting us, and to defeat competing tribes in combat. Spears with fire-hardened points were in use millenia before stone points, which survive until the present, appeared on the scene.

Ape hands continued to specialize while ours remained suited for general purpose tech utilization, for grasping, twisting, pounding, and carrying.

Our numbers exploded as a result and man became the principle opponent of man. Competition among equals is what caused our brains to reach the unnatural and unsustainable size they are tiday.

And without healthy competition they quickly begin to deteriorate with each gen.
Smithder
2.3 / 5 (7) Jul 16, 2015
Science does a pretty good job of explaining the world around us, and that tends to be because we question our findings and conclusions repeatedly.

But we are ingenious creatures and can build a very convincing science around a false premise - the earth as the centre of the universe is but one example of an excellent working science with only a few awkward observations that could not be explained.

Today LCA is one of those faulty premises. LCA presumes every life form evolves linearly from one other life form - it totally fails to acknowledge hybridisation, while hybridisation is a part of all life around us and 'distant' hybrids give a clear solution to Darwin's Dilemma, i.e the persistent evidence of saltation in the fossil record.

At the moment, science is doing a grand job of fitting all the life forms into a tidy LCA 'Tree of Life'. It manages to do this by imposing some pretty rigid rules on what test to do and which tests to ignore.
Smithder
2.1 / 5 (7) Jul 16, 2015
Today, hybridologists have a good understanding of how hybridisation works and the signatures that hybrids will exhibit.

The hybrid will have low fertility caused by a high proportion of dysfunctional gametes.
It will have an unstable genome throwing up a rich diversity for natural selection to work on.
It will retain several traits characteristic of each parent.
It will likely exhibit hybrid vigour and may contain some novel functionality caused either by gamete mutation or as a consequence of having two competing or reinforcing genomes at work simultaneously.

Humans exhibit all the traits of a newly formed hybrid.

We have not evolved from an LCA, we are a hybrid - newly formed with all our bits and pieces, hands included, being a consequence of our new hybrid genome.

Once we allow our science to open its mind to the fallacy of the LCA linear evolution concept, the big questions jump out - what are our hybrid parents and when did we hybridise?
tadchem
5 / 5 (1) Jul 16, 2015
Specialization and adaptability are often mutually exclusive.
Specialization, as seen in the the fingers of the loris or the aye-aye, allows a species to occupy a niche often avoided by likely competitors. This provides survival security - as long as the niche endures.
Adaptability is facilitated by the lack of specialization, and allows a species to move quickly from one niche to another. This provides survival security when a niche does not endure.
Adapt or die.
Smithder
2.3 / 5 (6) Jul 16, 2015
In this respect, hybridisation is the opposite of speciation.

Hybrids are highly variable and poorly fertile to the point of near non viability. But, if their hybrid form has an advantage, they prevail, even to the point of outdoing their parents and many other species along the way (see humans as a good example).

Hybrids soon become subject to natural selection and start the long road to speciation.

Species are highly optimised for their niche but have lost most of their genetic variability, and as you point out tadchem, the moment some intervention challenges or destroys their niche, they are doomed to extinction (see the impact of humans on many species)
HeloMenelo
5 / 5 (2) Jul 19, 2015
The gentle gorilla ....

Really?
https://www.youtu...aLo95ufw


yes thats you.. the anti science gorilla remember lol... ;)
viko_mx
1 / 5 (4) Jul 19, 2015
"Entropy can decrease locally (however globally it always increases). "

This can happen locally or globaly only due to inteligent action embodying the idea of reducing the entropy through controlled use of matter and energy following previously considered plan and technology. Entropy can not decrease willfully thanks to random events. If it could, it would reduce both locally and globally thanks to the principle of superposition valid for homogeneous systems. Physical laws do not make or increase order. These only keep originally established ordeр for a while. And do not increase information in the system. Only keep it for a while.
I wonder why you not abandon the illusory world in which you live? From what do you run? Delusion is useless and pointless activity.
TheGhostofOtto1923
4.2 / 5 (5) Jul 19, 2015
I wonder why you not abandon the illusory world in which you live? From what do you run? Delusion is useless and pointless activity
-This from the guy who lives under the delusion that his god would lie to him about the past in order to find out how much viko trusts him.

This from the guy who lives under the delusion that he can believe all those promises in his holy book about immortality, wish-granting, absolution, and retribution from the god who writes verified lies about the past in the same book.

Delusion is your forté viko.
Smithder
5 / 5 (4) Jul 19, 2015
"Entropy can decrease locally (however globally it always increases). "

This can happen locally or [sic]globaly only due to [sic]inteligent action.


Yes it can, but it is not exclusively so.

A crystal of salt can form by the evaporation of seawater. The local order formed by the crystallisation is not a matter of intelligent action.

I also agree with the last statement you made "I wonder why you not abandon the illusory world in which you live? From what do you run? Delusion is useless and pointless activity." I would suggest that you challenge yourself with that very statement.
TheGhostofOtto1923
5 / 5 (3) Jul 20, 2015
Only the efforts of intelligent being made possible the emergence of complex structures with intended functionality in our physical reality
-Perhaps. But it wouldn't be YOUR intelligent being because he writes a book about people we know never existed and events we know never happened.

So we can conclude with confidence that YOUR intelligent being couldn't compose a universe because he doesn't even know what happened 2000 years ago.
Smithder
5 / 5 (4) Jul 20, 2015
@Ren82
Viko made the silly claim that order can only be brought about "only due to inteligent action". This statement has been shown to be fiction, you even substantiated his error with your example of the snowflake.

Now you are making the claim that the physics that sets these processes will do so "just for a while". Please tell us where you found this revelation, or is this just another personal delusion like Viko's, to help you blank out the reality that science is grinding out in front of you?
Smithder
3 / 5 (2) Jul 21, 2015
Getting back to the point in hand (sorry, couldn't help that...)

When an F1 hybrid is formed, it has a complete copy of each parent's genome. Consequently, it tends to be a mishmash, almost a chimera, of characteristics from each parent (see the Zeeborse as an excellent example). But when that F1 attempts to reproduce and form its own sexual gametes, the cellular machinery involved does a random job (i.e. no intelligence involved) of making a uniform genome from the two mismatched parents. The consequence is that a major proportion of the gametes are not viable (giving rise to the fiction that all hybrids are sterile).

But when the F1 does manage to breed back with one of the parent lines, a mishmash creature is formed with complete or partial phenotypical characteristics from each parent. This new life form has not evolved in the classical Darwinian manner, its form is a consequence of hybridisation, later to be sculpted by natural selection.
Smithder
2.3 / 5 (3) Jul 21, 2015
As a hybrid, our ability to walk and run for long distances, is not something we have evolved, it is something our hybrid was born with, just like our hands and the proto hooves we have at the ends of our fingers, we don't need them, we were just born with them.

Our skin is far from ape like. we have no pelt, we are for all practical purposes, hairless. We have essentially inherited our skin from our other parent. We have an insulating fat layer, controllable sweat glands and a controllable blood supply through the insulating fat layer to the skin surface. We did not evolve it, it is a direct contribution from our other parent.

The point here is, when hybridisation gets involved, LCA becomes a meaningless concept, and attempts to force our science to fit inconvenient facts can be very embarrassing for a while - at least until we accept that we have to improve our model to accommodate the stubborn and sometimes uncomfortable facts.
Smithder
3 / 5 (2) Jul 21, 2015
Today, religion and some aspects of science are both at odds with reality.

But as the song by Christina Perry goes -'We are only human', and sometimes our egos get in the way of accepting truths about the world, - particularly about ourselves - look how crazy some of us went (and still are) when Darwin explained that we had evolved from some inferior ape like creature... How hard then is it to accept that we are not an evolved super creature, but a mongrel hybrid from some ungodly coupling in the forest followed by incestuous back breeding with our mamma's troop.

Oh - now, that is uncomfortable...

LOL will we ever survive the shame?

Smithder
5 / 5 (2) Jul 21, 2015
@Ren82

Please answer my question first, then I will be happy to respond to yours.
Koolokamba
1 / 5 (1) Jul 21, 2015
Ren82 Smithder A mule is ordered, as much as any other type of organism. And yet, it's the accidental product of a mating between a horse and an ass.
Smithder
3 / 5 (2) Jul 21, 2015
@Koolokamba

Indeed a mule is ordered, but not quite as much as a stabilised species such as the horse or the ass, it is an F1 hybrid and its gametes are so damaged and variable, it is almost sterile.

And, if you have ever seen a stallion mounting a jenny, you would know there is absolutely nothing accidental about it, nor its consequence.

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