Scientists have unearthed remains of a primate that could have been ancestral not only to humans but to all great apes, including chimps and gorillas. Posted on 02/18/2007 11:40:54 PM PST by LibWhacker
Scientists have unearthed remains of a primate that could have been ancestral not only to humans but to all great apes, including chimps and gorillas.
The partial skeleton of this 13-million-year-old "missing link" was found by palaeontologists working at a dig site near Barcelona in Spain.
Details of the sensational discovery appear in Science magazine.
The new specimen was probably male, a fruit-eater and was slightly smaller than a chimpanzee, researchers say.
Palaeontologists were just getting started at the dig when a bulldozer churned up a tooth.
Further investigation yielded one of the most complete ape skeletons known from the Miocene Epoch (about 22 to 5.5 million years ago).
Salvador Moyà-Solà of the Miquel Crusafont Institute of Palaeontology in Barcelona and colleagues subsequently found parts of the skull, ribcage, spine, hands and feet, along with other bones.
They have assigned it to an entirely new genus and species: Pierolapithecus catalaunicus .
Monkey business
Great apes are thought - on the basis of genetic and other evidence - to have separated from another primate group known as the lesser apes some time between 11 and 16 million years ago (The lesser apes include gibbons and siamang).
It is fascinating, therefore, for a specimen like Pierolapithecus to turn up right in this window.
Scientists think the creature lived after the lesser apes went their own evolutionary way, but before the great apes began their own diversification into different forms such as orang-utans, gorillas, chimps and, of course, humans.
" Pierolapithecus probably is, or is very close to, the last common ancestor of great apes and humans," said Professor Moyà-Solà.
The new ape's ribcage, lower spine and wrist display signs of specialised climbing abilities that link it with modern great apes, say the researchers.
The overall orthograde - or upright - body design of this animal and modern-day great apes is thought to be an adaptation to vertical climbing and suspending the body from branches.
The Miocene ape fossil record is patchy; so finding such a complete fossil from this time period is unprecedented.
"It's very impressive because of its completeness," David Begun, professor of palaeoanthropology at the University of Toronto, Canada, told the BBC News website.
"I think the authors are right that it fills a gap between the first apes to arrive in Europe and the fossil apes that more closely resemble those living today."
Planet of the apes
Other scientists working on fossil apes were delighted by the discovery. But not all were convinced by the conclusions drawn by the Spanish researchers.
Professor Begun considers it unlikely that Pierolapithecus was ancestral to orang-utans.
"I haven't seen the original fossils. But there are four or five important features of the face, in particular, that seem to be closer to African apes," he explained.
"To me the possibility exists that it is already on the evolutionary line to African apes and humans."
Professor David Pilbeam, director of the Peadbody Museum in Cambridge, US, was even more sceptical about the relationship of Pierolapithecus to modern great apes: "To me it's a very long stretch to link this to any of the living apes," he told the BBC News website.
"I think it's unlikely that you would find relatives of the apes that live today in equatorial Africa and Asia up in Europe.
"But it's interesting in that it appears to show some adaptations towards having a trunk that's upright because it's suspending itself [from branches].
"It also has some features that show quadrupedal (four-legged) behaviour. Not quadrupedal in the way chimps or gorillas are, but more in the way that monkeys are - putting their fingers down flat," he explained.
During the Miocene, Earth really was the planet of the apes.
As many as 100 different ape species roamed the Old World, from France to China in Eurasia and from Kenya to Namibia in Africa.
"The classic argument of the epistemophobic.
You learn a new word, you think you have a new fact. :)
Humans did not descend from african apes. Of this I'm sure.
Good idea.
Right it off as just another initially interesting science thread high-jacked by the deliberately ignorant.
Spot on.
Thanks. :-)
I want to see the fish walk out of the water video that Disney did. What more do you need to see?
Pray for W and Our Troops
Humans are primates, not apes, although I've seen some people who would make you wonder...
I once wrestled a guy from western PA that certainly met that description.
So if the chimps are mainly fruit eaters and have canines that size, why did we humans, who are omnivores and have much more need for canines, end up with the greatly reduced in size ones? You'd think, that the canines were more necessary for a creature that have meat as main part of it's diet.
For that matter, why on earth would we have lost the the fur that covers all the other hominids? What kind of evolutionary advantage would that afford, to be MORE exposed to the elements?
Along with the helplessness of our infants and the burden they place on the mother.
Humans are not well suited for unprotected life in the wild. It does not make sense that the genetic changes that produced a weaker creature would have allowed the creature to so successfully reproduce and flourish.
Brains alone don't ensure survival.
We developed tool use. Canines are of little use in eating fruit, but they are very useful in fighting. The Homo line developed tools to do the fighting for them, and the canines tapered off accordingly.
For that matter, why on earth would we have lost the the fur that covers all the other hominids? What kind of evolutionary advantage would that afford, to be MORE exposed to the elements?
There are a couple of possibilities. One would be change in environment and development of hunting. Running after prey in the open, sunny plains, would require a better cooling system than apes had in the hot but moist forests.
Along with the helplessness of our infants and the burden they place on the mother.
That is also an ape trait.
Humans are not well suited for unprotected life in the wild. It does not make sense that the genetic changes that produced a weaker creature would have allowed the creature to so successfully reproduce and flourish.
The change to "weakness" was allowed by the development of a wide range of tools and culture. It did not happen in isolation.
Brains alone don't ensure survival.
Of course not. But tools and culture are extremely important in our survival, and the degree that humans possess these traits far outstrips the rest of the primates. These traits are almost certainly associated with the increased brain size.
(Good questions by the way.)
Although I don't agree with your conclusion here, I can certainly understand the reasoning behind it
The gradual regression of this genetic expression on the population level, to my understanding, had to be the result of either Genetic Drift, or Natural Selection.
1) Genetic Drift.
According to evolutionary biologist, Douglas Futuyma, Genetic Drift is entirely random, and in those cases where the trait is neutral to survival and reproduction, it is not subject to natural selection1
I think you would agree that isn't the case here, not only because the trait isn't neutral to survival, but because the random nature of the genetic expression would falsify any correlation to the advent of tool use.
2) Natural Selection
This seems to be the only mechanism, along with mutation and/or recombination, that can account for the regression and dominance of the trait within a population, and lend support for a causal relationship (even if by argument) to tool use.
The problem is, since the expression of the trait itself is random, then at any given time, and at any given step of the regression, those organisms will be competing with otherwise normal, fit, organisms of the same species, at the same time, within the same population.
It follows that any morphological change that isn't neutral, which your proposition is not since it effects survival, must be equal to, or greater than, the morphological benefits of a normal, fit organism of the same species it is in competition with. Anything less than equivalence would immediately infer a disadvantage, and grounds for falsification that it would dominate a population.
In short, the adaptability of mutated organism A, must at least be equal to the adaptability of normal organism B, throughout the entire process of morphological change from generation to generation. Each new instantiation must be equal to the one preceding it, reducible of course, to it's normal fit state.
Although it's possible that the trait would dominate a population, I simply don't see any selective advantage that it would do so.
------------------------
Sources/notes
1. "You can’t have any evolutionary change whatever without mutation, and perhaps recombination, giving rise to genetic variation. But once you have genetic variation, there are basically two major possibilities: First, there is simply no difference between the different genotypes or different genes in their impact on survival or reproduction, and in that case, you can have random changes of one versus the other type in a population or a species until eventually one replaces the other. That is an evolutionary change. It happens entirely by chance, by random fluctuations. That is what we call the process of genetic drift. * Genetic drift is very different from possibility number two, natural selection..."
Interview with Douglas Futuyma
But would that offset the protective advantages fur would offer. Virtually all the rest of the mammalian predators in nature are fur covered and they seem to have managed, even on the open plains.
Are other ape infants as helpless for as long as human infants? Any I've seen at the zoos are at least clinging to their mothers back at a very young age. Human infants can't even do that. Another disadvantage of fur loss, aside from protection to cold and UV.
If we indeed do use only 10% of our brains, then how is brain size significant? One could conclude that the skull size could be significantly reduced and still produce as intelligent a creature. It would just be a matter of using proportionately more of the brain, even though the same amount would be used in each case. Don't Pygmies have smaller cranial size to match their stature, and are they less intelligent? How do their brain sizes compare to that of mose apes and chimps?
One group of apes evolved into humans. Another group evolved into the modern ape.
Since there may be numerous individuals within the same population that are equally fit for different reasons, you would have to explain the dominance of a given trait within this seeming disparity...and natural selection, to my knowledge is the only mechanism that can account for this.
Furthermore, I was under the impression that we're not talking about convergent evolution, i.e., the spread of similar traits within isolated, or dislocated populations.
That said, I'm not sure how your scenarios would account for the pervasiveness of any given trait, let alone the one we're talking about here. It seems completely incoherent to me and disassociated with the principles of evolutionary theory.
I could be wrong, but that's just my opinion
You know, I was just getting me a scoop of ice-cream with my back-ho while reading this article....
/silly
Hey, another nice recommendation, thanks!
Wow, bookmarked it but it looks like it's way too advanced for me! Thank you, though; I never know when I might really get interested enough in something like that to tackle it head on.
>>Hey, another nice recommendation, thanks!<<
You are most welcome. It sure is easy for a non-biologist like myself to quickly get to jargon I don't understand - good clear references that talk about advanced issues but don't use advanced jargon and are still accurate are few and far between.
They aren't? I'm pretty sure that every organism that has even one neuron (like the 'mentally challenged' lowly Caenorhabditis elegans, a very simple worm) is using that neuron to improve their lot. You're going to have to do better than that.
As a result of language studies in chimps, we now know that they are aware of themselves and their future, and they can communicate that fact.
Just in terms of your first example (the breast cancer) - that is exactly why cancer is one of the leading killers in developed countries today. Almost all cancers begin in middle or old age. Why? Because there was no selective advantage to staying alive to that age. After women go through menopause, they can't reproduce. Evolution picks traits that are good for continued reproduction.
If there was a gene for dying at age 50 in women, evolution would essentially ignore that gene. Because by age 50, women have had all the children they're going to have. If there was a gene for 'living past age one,' then that gene would be overrepresented in the gene pool, as people who did not have that gene would not have children. However, the gene for 'living past age 50' is not going to be overrepresented in the gene pool, as women can't have children past that age.
So it's not really a coincidence that most cancers start striking once people have reached the end of their reproductive life span. Evolution has made it that way.
So where is the chimp hospital?
Where is the chimp automobile?
Or are you calling Chimps smoking ciggarettes improvement?
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