Posted on 12/17/2007 1:50:35 PM PST by blam
Ape To Human: Walking Upright May Have Protected Heavy Human Babies
For safety, all nonhuman primates carry their young clinging to their fur from birth, and species survival depends on it. (Credit: iStockphoto/Graeme Purdy)
ScienceDaily (Dec. 17, 2007) — The transition from apes to humans may have been partially triggered by the need to stand on two legs, in order to safely carry heavier babies. This theory of species evolution presented by Lia Amaral from the University of São Paulo in Brazil has just been published online in Springer’s journal, Naturwissenschaften.
For safety, all nonhuman primates carry their young clinging to their fur from birth, and species survival depends on it. The carrying pattern changes as the infant grows. Newborns are carried clinging to their mother’s stomach, often with additional support. Months later, infants are carried over the adult body usually on the mother’s back, and this carrying pattern lasts for years in apes. However, this necessity to carry infants safely imposes limits on the weight of the infants.
Through a detailed mechanical analysis of how different types of apes - gibbons, orangutans and gorillas - carry their young, looking at the properties of ape hair, infant grip, adult hair density and carrying position, Amaral demonstrates a relationship between infant weight, hair friction and body angle which ensures ape infants are carried safely.
Amaral also shows how the usual pattern of primate carrying of heavy infants is incompatible with bipedalism. African apes have to persist with knuckle-walking on all fours, or ‘quadruped’ position, in order to stop their young from slipping off their backs.
The author goes on to suggest that the fall in body hair in primates could have brought on bipedality as a necessary consequence, through the strong selective pressure of safe infant carrying, as infants were no longer able to cling to their mother’s body hairs. In the author’s opinion, safe carrying of heavy infants justified the emergence of the biped form of movement. Although an adult gorilla is much heavier than an adult human, its offspring is only half the weight of a human baby.
Amaral concludes that this evolution to bipedality has important consequences for the female of the species. Indeed, it frees the arms and hands of males and juveniles, but females have their arms and hands occupied with their young. This restriction of movement placed limits on food gathering for biped females carrying their infants, and may have been at the origin of group cooperation.
Reference: Amaral LQ (2007). Mechanical analysis of infant carrying in hominoids. Naturwissenschaften (DOI 10.1007/s00114-007-0325-0).
Adapted from materials provided by Springer.
Or then there is the obvious... If you don’t have to walk on all fours, then you can use your hands for something else.
Yeah, right. Women know better.
I think that's when the saying, "Monkeying around with your privates" all began ...
Evolution is not triggered by “needs;” it is triggered by random, uncontrolled(able) gene mutations that have nothing to do with the life experience of the parent.
This is the usual LaMarckian popular science drivel.
“Evolution is not triggered by “needs;” it is triggered by random, uncontrolled(able) gene mutations that have nothing to do with the life experience of the parent.”
Yes, but the point of evolution is that, among the many gene mutations that occur, some make it more likely that the affected individual will survive to produce offspring. If, for instance, walking upright made it more likely that the offspring would be born, then that mutation would be more likely to be passed on to the next generation, regardless of whether it had any other appreciable effect on the life experience of the parent.
The “randomness” may simply be changes caused by changes in nutrition or other environmental factors that could not be predicted at the time of birth.
There are an incredible number of mutations that would have been necessary to simultaneously transform a knuckle dragger into a fully functional 2-legged walker, e.g., dramatic changes to the inner ear which regulates balance.
What good would a slight genetic change do that caused a four legged walker to slightly rear up??
This is a huge problem with this idea of 4 to 2 legged transition.
The only real advantage could be that your hands are now free, but how often do we use our hands when in motion? Most hunting and gathering can be done while sitting or standing in place
... or maybe God knew what he was doing :)
Oh yeah, science is so evil....LOL...
I saw a dinosaur the other day... he said he never existed but instead was a magical “test” by our lord.... Xinua from the planet Zorocan.
I'd call this an hypothesis.
Gotta love science!! With this new info I am armed and dangerous.
Who said science was evil? Why do you presume that creation and science are incompatible? In fact, it’s nice to see that science has come around on the question of whether the universe was enternal. Three cheers for God and his big bang!
Why do you assume "knuckle-dragger" to bipedalism is the only possible mechanism?
How about brachiator to various terrestrial adaptations, including both bipedalism and knuckle-walking?
Well, *she's* a lesbian. ;')Pregnant? Backache? Thank evolutionPregnant women may stand out a mile away with their characteristic backward-leaning stance, but that clumsy-looking position is a unique adaptation that evolved over millennia... Pregnant pre-humans appeared to have stood the same way. And it may save women from even more back pain than they already have... The bodies of women do two things when they are pregnant -- they adjust their stance to move the center of gravity to accommodate the growing fetus, and the lower vertebrae have evolved a distinct shape to allow this shifting to take place without damaging the spine... Whitcome and Shapiro followed 19 women through their pregnancy, using digital cameras and motional analysis equipment to map the changes in stance and movement as the months passed... Without this change in shape, the vertebrae could be subject to shearing forces, with one sliding over another, damaging the fluid-filled discs in between or pulling on ligaments and muscles... When she moved to Harvard, Whitcome continued the study and looked at the fossils of pre-humans known as australopithecenes, as well as at the bone structure of our nearest living relatives, the chimpanzees... Men do not have this adaptation, either, Shapiro said... "They probably lean back the same way to try and balance that load, but they are kind of putting their vertebrae more at risk. I am sure there has got to be a correlation between having a big beer gut and having back pain," Shapiro laughed.
by Maggie Fox
Health and Science Editor
Reuters
Wednesday, December 12, 2007
ed. by Will Dunham and Sandra Maler
I guess the some apes just refused to stand up in an effort to avoid putting on clothes and going to work. These are probably the apes that want to hold on to their culture. I have a neighbor that appears as though he's reverting back to an ape. He even put up a tire swing for his kids.
|
|
|||
Gods |
Thanks Blam. |
||
|
· Mirabilis · Texas AM Anthropology News · Yahoo Anthro & Archaeo · · History or Science & Nature Podcasts · Excerpt, or Link only? · cgk's list of ping lists · |
|||
Ape to human evolution simply is not possible. One it would take trillions of years (do your own google searches on ‘haldane dilemma’)and two, there is nothing in the fossil record which we could plausibly be descended FROM. The neanderthal has been ruled out as an ancestor because of the genetic gulf and other hominids were all more primitive than the neanderthal. On top of that, a recent study demonstrated that several skeletons once thought to be human/neanderthal hybrids were all modern humans and that there ARE NO human/neanderthal hybrids and no possibility of any genetic relationship between ourselves and hominids. Hominids including the neanderthal were advanced apes and nothing more, and we are not related to any of them in any way, shape, or manner.
Haldane’s dilemma is easily addressed on a number of levels. The first being that no one actually knows if there’s any dilemma real at all (http://www.gate.net/~rwms/haldane1.html), and other being more mathematically-based than can be properly expressed in a forum like these. You can see the work in the link. Your trillions number is completely made up unless you care to share your math.
“no possibility of any genetic relationship between ourselves and hominids.”
How odd, considering you and I are hominids. Pardon me if I am skeptical of you scientific “research” since you don’t seem remotely aware of your own taxonomy.
“but how often do we use our hands when in motion?”
You don’t drive on 195 in Miami during rush hour do you?
You post is a mix of opinion, wishful thinking, misinterpretations, and outright errors. It bears no relationship to actual science or scientific discoveries.
Thus the invention of the carry bag and the baby sling...
The ‘aquatic ape theory’ also accounts for adaptations such as lack of body hair, prominent noses and webbed fingers.
gnip...
Allow me to explain the dilemma for you and then see if you still believe that.
Imagine a population of 100,000 apes or “proto-humans” ten million years ago which are all genetically alike other than for two with a “beneficial mutation”. Imagine also that this population has the human or proto-human generation cycle time of roughly 20 years.
Imagine that the beneficial mutation in question is so good, that all 99,998 others die out immediately (from jealousy), and that the pair with the beneficial mutation has 100,000 kids and thus replenishes the herd.
Imagine that this process goes on like that for ten million years, which is more than anybody claims is involved in “human evolution”. The max number of such “beneficial mutations” which could thus be substituted into the herd would be ten million divided by twenty, or 500,000 point mutations which is about 1/100 of one percent of the human genome, and a miniscule fraction of the 2 to 3 percent that separates us from chimpanzees, or the half of that which separates us from neanderthals.
In other words, even given an outrageous rate of substitution which will never happen in real life, in ten million years, starting from an ape, you'd still be an ape. Maybe an ape with a slightly shorter tail, but that would be every bit of it.
This is simple stuff and nobody should need to be Albert Einstein to grasp it. Anybody claiming this one has been dealt with is lying.
I could explain some of your errors to you, but I doubt it is worth the effort. You didn't learn a thing the last time I tried; you keep making the same silly mistakes.
At some point you should be able to stop taking the ignorance pills, i.e. you’ve basically arrived...
Whether you were born upright or down on all fours, you would still be the same species.
You can NOT evolve into a new species!
Human Ancestors Went Out Of Africa And Then Came Back... [1998]
ScienceDaily | Friday, August 7, 1998 | adapted from New York University materials
Posted on 12/17/2007 8:37:11 PM EST by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1940963/posts
The point is that 2 to 3% difference in a genome can be the product of one mutation. You do not need one mutation for each gene that changes. Every human guanine that is a chimpanzee cytosine is not necessarily independent from any other novel nucleotides.
Haldane also dismisses simultaneous beneficial substitutions out of hand, as using a narrow definition of genetic load, as well assuming an entirely heterozygotic genotype.
“The genotype with heterozygosis at all loci is so far outside this range that neither it nor anything approaching it ever occurs in the population. It is absurd to suppose that all genotypes produce as many offspring as would be produced by this 100-fold heterozygote, if it existed, but that these are reduced to infinitesimal numbers by the cumulative selective coefficients where there is homozygosis at 35 or more loci. Thus the load relative to the 100-fold heterozygote is meaningless. It would be more appropriate to take as a reference genotype one that is above the average by only two or three standard deviations.”” - Sewall Wright
Of course you can’t evolve once you’ve been born, you silly goose. Unless a radioactive spider gets his fangs on you.
Clever way of trying to claim you can have multiple mutations at once. Not in real life. In real life the vast bulk of all mutations are detrimental to fatal so that a group of animals undergoing any more than one mutation at one time would go extinct.
Sorry, wrong again.
(Where do you come up with this nonsense?)
The point is that one mutation can account for an unknown percentage of genetic change. Let’s say that the homo sapiens genome is about .5% different from the homo neanderthalensis genome (which considering the recent research on preserved Neanderthal DNA, it seems to be), meaning about 3 million bases differ between us and the Neanderthal. Those 3 million bases are not, as you and Haldane might suppose, the evidence of 3 million individual mutations. A small number of individual mutation events can change a large number of bases.
I think it’s even more important to note that no biologist actively doing genetic research would seriously consider Haldane’s dilemma as strong evidence against evolution via natural selection. Haldane didn’t, Wright didn’t, John Maynard Smith didn’t, no one has who isn’t emotionally invested in promoting a Creation myth.
Even if you consider Haldane’s initial methods to be strong (even Haldane didn’t), it’s not evidence that there is any particular weakness in the idea that all genomes mutate and some mutations are stronger than others, and those mutations will move throughout populations and effect its genotype. It is merely a mathematical model of a very specific situation which, while it mimics some genetic events in some populations, is not a particularly excellent model of the way new genetic material is selected for or against in populations of any given size.
Origin Of Bipedalism Closely Tied To Environmental Changes
Space Daily | 05-01-2002 | staff writer at Space Daily
Posted on 05/29/2002 5:11:46 PM EDT by Salman
http://www.freerepublic.com/focus/f-news/691468/posts
Early Human Ancestors Walked On The Wild Side
Eureka Alert - ASU | 2-16-2006 | Garu Schwartz - Skip Derra
Posted on 02/16/2006 1:14:54 PM EST by blam
http://www.freerepublic.com/focus/f-chat/1579810/posts
Early Humans Walked Peculiarly
Discovery News | 2-28-2006 | Jennifer Viegas
Posted on 02/28/2006 2:27:44 PM EST by blam
http://www.freerepublic.com/focus/f-news/1587166/posts
Ancient Humans Walked But ‘Struggled To Run’
The Telegraph (UK) | 9-11-2007 | Roger Highfield and Nic Fleming
Posted on 09/11/2007 10:51:26 AM EDT by blam
http://www.freerepublic.com/focus/f-news/1894625/posts
Other than that, I've seen all sorts of arguments against the dilemma and the only person I've ever heard or read making the argument you are trying to make is you.
BTTT.
Allow me to explain the dilemma for you and then see if you still believe that.
From Index to Creationist Claims:
Claim CB121:J. B. S. Haldane calculated that new genes become fixed only after 300 generations due to the cost of natural selection (Haldane 1957). Since humans and apes differ in 4.8 × 107 genes, there has not been enough time for difference to accumulate. Only 1,667 nucleotide substitutions in genes could have occurred if their divergence was ten million years ago.
Source:
ReMine, Walter J., 1993. The Biotic Message, St. Paul Science, Inc.Response:
Links:
- Haldane's "cost of natural selection" stemmed from an invalid simplifying assumption in his calculations. He divided by a fitness constant in a way that invalidated his assumption of constant population size, and his cost of selection is an artifact of the changed population size. He also assumed that two mutations would take twice as long to reach fixation as one, but because of sexual recombination, the two can be selected simultaneously and both reach fixation sooner. With corrected calculations, the cost disappears (Wallace 1991; Williams n.d.).
Haldane's paper was published in 1957, and Haldane himself said, "I am quite aware that my conclusions will probably need drastic revision" (Haldane 1957, 523). It is irresponsible not to consider the revision that has occurred in the forty years since his paper was published.
- ReMine (1993), who promotes the claim, makes several invalid assumptions. His model is contradicted by the following:
- The vast majority of differences would probably be due to genetic drift, not selection.
- Many genes would have been linked with genes that are selected and thus would have hitchhiked with them to fixation.
- Many mutations, such as those due to unequal crossing over, affect more than one codon.
- Human and ape genes both would be diverging from the common ancestor, doubling the difference.
- ReMine's computer simulation supposedly showing the negative influence of Haldane's dilemma assumed a population size of only six (Musgrave 1999).
Williams, Robert, n.d. Haldane's dilemma. http://www.gate.net/~rwms/haldane1.html
References:
- Haldane, J. B. S., 1957. The cost of natural selection. Journal of Genetics 55: 511-524.
- Musgrave, Ian, 1999. Weasels, ReMine, and Haldane's dilemma. http://www.talkorigins.org/origins/postmonth/sep99.html
- ReMine, Walter J., 1993. The Biotic Message, St. Paul Science, Inc.
- Wallace, Bruce, 1991. Fifty Years of Genetic Load - An Odyssey. Cornell University Press. See particularly Chapters 5, 6, 8, and 9.
- Williams. (See above)
Ok, I think I get it.
If I make my bride carry a monkey on her back, my hair will grow back.
I just hope it will be in time for Christmas.
It’s from the page I linked to you. I have given you two different rebuttals, one from Sewell Wright and one from Warren Ewens. Ewens is by far the best-knownand most successful critic of Haldane’s Dilemma and is pretty widely considered to have solved it.
That you haven’t heard of them is, I promise you, not even the tiniest bit surprising.
Ewens, W. J. 1970 Remarks on the Substitutional Load Theoretical Population Biology 1:129-139
Ewens, W. J. 1972 The Substitutional Load in a Finite Population American Naturalist 106:273-282
Ewens, W. J. 1972 Concepts of Substitutional Load in Finite Populations Theoretical Population Biology 3:153-161
Like I say, I offered you a very simple explanation of the thing above, and nobody needs anything more than counting-style math to grasp it; I don’t view the idea of a refutation of that as possible or conceivable.
There are more things in heaven and earth, Horatio,
Than are dreamt of in your philosophy.Hamlet Act 1, scene 5
That site is apparently run by Wally ReMine (of "baraminology" fame).
Why should we trust anything he says about science?
A hunting attack is quick, either you caught it or you didn't, but tribal warfare requires wielding weapons for extended periods of time since your battle opponent is about the same in capabilities. Armpit hair and sweat under stress provides needed lubrication for an extended fight, which no other animal has a need for. War is a special high speed form of evolution in that any advantage in genetics, culture, technology, teammanship is selected for in a few years rather than the many thousands of years natural selection takes. The losing side is often decisively and entirely killed off.
who was saying that? the truth is we didn’t come from apes. we did, however, have a common ancestor.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.