Posted on 08/11/2002 3:59:04 PM PDT by vannrox
August 6, 2002Skulls Found in Africa and in Europe Challenge Theories of Human OriginsBy JOHN NOBLE WILFORD
Probably so, according to paleontologists, who may have to make major revisions in the human genealogy and rethink some of their ideas about the first migrations out of Africa by human relatives. Yet, despite all the confusion and uncertainty the skulls have caused, scientists speak in superlatives of their potential for revealing crucial insights in the evidence-disadvantaged field of human evolution. The African skull dates from nearly 7 million years ago, close to the fateful moment when the human and chimpanzee lineages went their separate ways. The 1.75-million-year-old Georgian skull could answer questions about the first human ancestors to leave Africa, and why they ventured forth. Still, it was a shock, something of a one-two punch, for two such momentous discoveries to be reported independently in a single week, as happened in July. "I can't think of another month in the history of paleontology in which two such finds of importance were published," said Dr. Bernard Wood, a paleontologist at George Washington University. "This really exposes how little we know of human evolution and the origin of our own genus Homo." Every decade or two, a fossil discovery upsets conventional wisdom. One more possible "missing link" emerges. An even older member of the hominid group, those human ancestors and their close relatives (but not apes), comes to light. Some fossils also show up with attributes so puzzling that scientists cannot decide where they belong, if at all, in the human lineage. At each turn, the family tree, once drawn straight as a ponderosa pine, has had to be reconfigured with more branches leading here and there and, in some cases, apparently nowhere. "When I went to medical school in 1963, human evolution looked like a ladder," Dr. Wood said. The ladder, he explained, stepped from monkey to modern human through a progression of intermediates, each slightly less apelike than the previous one. But the fact that modern Homo sapiens is the only hominid living today is quite misleading, an exception to the rule dating only since the demise of Neanderthals some 30,000 years ago. Fossil hunters keep finding multiple species of hominids that overlapped in time, reflecting evolutionary diversity in response to new or changed circumstances. Not all of them could be direct ancestors of Homo sapiens. Some presumably were dead-end side branches. So a tangled bush has now replaced a tree as the ascendant imagery of human evolution. Most scientists studying the newfound African skull think it lends strong support to hominid bushiness almost from the beginning. That is one of several reasons Dr. Daniel E. Lieberman, a biological anthropologist at Harvard, called the African specimen "one of the greatest paleontological discoveries of the past 100 years." The skull was uncovered in the desert of Chad by a French-led team under the direction of Dr. Michel Brunet of the University of Poitiers. Struck by the skull's unusual mix of apelike and evolved hominid features, the discoverers assigned it to an entirely new genus and species Sahelanthropus tchadensis. It is more commonly called Toumai, meaning "hope of life" in the local language. In announcing the discovery in the July 11 issue of the journal Nature, Dr. Brunet's group said the fossils a cranium, two lower jaw fragments and several teeth promised "to illuminate the earliest chapter in human evolutionary history." The age, face and geography of the new specimen were all surprises. About a million years older than any previously recognized hominid, Toumai lived close to the time that molecular biologists think was the earliest period in which the human lineage diverged from the chimpanzee branch. The next oldest hominid appears to be the 6-million-year-old Orrorin tugenensis, found two years ago in Kenya but not yet fully accepted by many scientists. After it is Ardipithecus ramidus, which probably lived 4.4 million to 5.8 million years ago in Ethiopia. "A lot of interesting things were happening earlier than we previously knew," said Dr. Eric Delson, a paleontologist at the City University of New York and the American Museum of Natural History. The most puzzling aspect of the new skull is that it seems to belong to two widely separated evolutionary periods. Its size indicates that Toumai had a brain comparable to that of a modern chimp, about 320 to 380 cubic centimeters. Yet the face is short and relatively flat, compared with the protruding faces of chimps and other early hominids. Indeed, it is more humanlike than the "Lucy" species, Australopithecus afarensis, which lived more than 3.2 million years ago. "A hominid of this age," Dr. Wood wrote in Nature, "should certainly not have the face of a hominid less than one-third of its geological age." Scientists suggest several possible explanations. Toumai could somehow be an ancestor of modern humans, or of gorillas or chimps. It could be a common ancestor of humans and chimps, before the divergence. "But why restrict yourself to thinking this fossil has to belong to a lineage that leads to something modern?" Dr. Wood asked. "It's perfectly possible this belongs to a branch that's neither chimp nor human, but has become extinct." Dr. Wood said the "lesson of history" is that fossil hunters are more likely to find something unrelated directly to living creatures more side branches to tangle the evolutionary bush. So the picture of human genealogy gets more complex, not simpler. A few scientists sound cautionary notes. Dr. Delson questioned whether the Toumai face was complete enough to justify interpretations of more highly evolved characteristics. One critic argued that the skull belonged to a gorilla, but that is disputed by scientists who have examined it. Just as important perhaps is the fact that the Chad skull was found off the beaten path of hominid research. Until now, nearly every early hominid fossil has come from eastern Africa, mainly Ethiopia, Kenya and Tanzania, or from southern Africa. Finding something very old and different in central Africa should expand the hunt. "In hindsight, we should have expected this," Dr. Lieberman said. "Africa is big and we weren't looking at all of Africa. This fossil is a wake-up call. It reminds us that we're missing large portions of the fossil record." Although overshadowed by the news of Toumai, the well-preserved 1.75-million-year-old skull from Georgia was also full of surprises, in this case concerning a later chapter in the hominid story. It raised questions about the identity of the first hominids to be intercontinental travelers, who set in motion the migrations that would eventually lead to human occupation of the entire planet. The discovery, reported in the July 5 issue of the journal Science, was made at the medieval town Dmanisi, 50 miles southwest of Tbilisi, the Georgian capital. Two years ago, scientists announced finding two other skulls at the same site, but the new one appears to be intriguingly different and a challenge to prevailing views. Scientists have long been thought that the first hominid out-of-Africa migrants were Homo erectus, a species with large brains and a stature approaching human dimensions. The species was widely assumed to have stepped out in the world once they evolved their greater intelligence and longer legs and invented more advanced stone tools. The first two Dmanisi skulls confirmed one part of the hypothesis. They bore a striking resemblance to the African version of H. erectus, sometimes called Homo ergaster. Their discovery was hailed as the most ancient undisputed hominid fossils outside Africa. But the skulls were associated with more than 1,000 crudely chipped cobbles, simple choppers and scrapers, not the more finely shaped and versatile tools that would be introduced by H. erectus more than 100,000 years later. That undercut the accepted evolutionary explanation for the migrations. The issue has become even more muddled with the discovery of the third skull by international paleontologists led by Dr. David Lordkipanidze of the Georgian State Museum in Tbilisi. It is about the same age and bears an overall resemblance to the other two skulls. But it is much smaller. "These hominids are more primitive than we thought," Dr. Lordkipanidze said in an article in the current issue of National Geographic magazine. "We have a new puzzle." To the discoverers, the skull has the canine teeth and face of Homo habilis, a small hominid with long apelike arms that evolved in Africa before H. erectus. And the size of its cranium suggests a substantially smaller brain than expected for H. erectus. In their journal report, the discovery team estimated the cranial capacity of the new skull to be about 600 cubic centimeters, compared with about 780 and 650 c.c.'s for the other Dmanisis specimens. That is "near the mean" for H. habilis, they noted. Modern human braincases are about 1,400 cubic centimeters. Dr. G. Philip Rightmire, a paleontologist at the State University of New York at Binghamton and a member of the discovery team, said that if the new skull had been found before the other two, it might have been identified as H. habilis. Dr. Ian Tattersall, a specialist in human evolution at the natural history museum in New York City, said the specimen was "the first truly African-looking thing to come from outside Africa." More than anything else, he said, it resembles a 1.9-million-year-old Homo habilis skull from Kenya. For the time being, however, the fossil is tentatively labeled Homo erectus, though it stretches the definition of that species. Scientists are pondering what lessons they can learn from it about the diversity of physical attributes within a single species. Dr. Fred Smith, a paleontologist who has just become dean of arts and sciences at Loyola University in Chicago, agreed that his was a sensible approach, at least until more fossils turn up. Like other scientists, he doubted that two separate hominid species would have occupied the same habitat at roughly the same time. Marked variations within a species are not uncommon; brain size varies within living humans by abut 15 percent. "The possibility of variations within a species should never be excluded," Dr. Smith said. "There's a tendency now for everybody to see three bumps on a fossil instead of two and immediately declare that to be another species." Some discoverers of the Dmanisi skull speculated that these hominids might be descended from ancestors like H. habilis that had already left Africa. In that case, it could be argued that H. erectus itself evolved not in Africa but elsewhere from an ex-African species. If so, the early Homo genealogy would have to be drastically revised. But it takes more than two or even three specimens to reach firm conclusions about the range of variations within a species. Still, Georgia is a good place to start. The three specimens found there represent the largest collection of individuals from any single site older than around 800,000 years. "We have now a very rich collection, of three skulls and three jawbones, which gives us a chance to study very properly this question" of how to classify early hominids, Dr. Lordkipanidze said, and paleontologists are busy this summer looking for more skulls at Dmanisi. "We badly want to know what the functional abilities of the first out-of-Africa migrants were," said Dr. Wood of George Washington University. "What could that animal do that animals that preceded it couldn't? What was the role of culture in this migration? Maybe other animals were leaving and the hominids simply followed." All scholars of human prehistory eagerly await the next finds from Dmanisi, and in Chad. Perhaps they will help untangle some of the bushy branches of the human family tree to reveal the true ancestry of Homo sapiens.
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Other than that, you have not addressed the question of programmatic impossibilities:
Related features co-evolve. You have never in some X years addressed that all your personal models of evolution are too dumb to be pre-Lamarckian and thus irrelevant to science or logic.
Related features co-evolve.
What is the scientific basis for this statement? Is there something in the fossil record to demonstrate this? Has such a proclivity been demonstrated in laboratories? If true, does it apply to macro-evolution as well as micro-evolution?
If there's a large database of fossilized remains throughout history, it should be shown to apply across species. Has this been demonstrated by the record?
I don't know the answers to any of these questions, Vade. I'm just seeking answers to questions that pop into my head when I see a certain post such as yours. You seem to possess some degree of knowledge about these things. I'm hoping you can enlighten me.
Yours for a great weekend,
CA....
There are several fossil series which I have seen creationists actually try to debunk by stating that all creatures in the series seem integrated and fully functional. Well, duh! They seem integrated and fully functional precisely because if they weren't they'd be dead. The Darwinian model says exactly this; the creationist/medvedian strawman goes out of its way to say that first you have to evolve the wings, then the muscles, then the extra lungpower and by then some of the other stuff has de-volved because it was neutral or negative.
The Evidence for Dinosaur-Bird Transition. Note that, of all the fossil species represented, none seem freakishly unadapted although several are nearly halfway between dinosaur and bird. One (Confuciusornis) has that halfway claw/wing forelimb which so many strawman models say is a barrier because it can't be good for anything.
Here are reptiles becoming mammals. The multi-part reptile jawbone breaks up and becomes a single jaw bone plus some extra ear bones. (Reptiles, IIRC, have a single ear bone and hear best with their heads on the ground to pick up vibrations.)
The top two skulls are early mammals. The rest are increasingly old mammal-like reptiles except the bottom one, Hylonomus, is a probably ancestral very early reptile. This material is from The Fossil Record by Clifford Cuffey. The narrative therein relates that the insurmountable transition was made by a useful double jaw joint visible in some of the creatures. There was no "impossible freak" stage and the necessary changes happened together.
What is the scientific basis for this statement?
Imagination...
You have the evolutionists pegged right there. They keep saying they have morals and that they do not believe in might makes right, however, they will pull any dirty trick, any low tactic they can think of to discredit an opponent.
He answered the questions in three <3> posts just above. Have you no shame??????
Why bother to read the thread eh? Just shoot from the hip. People that have no shame don't bother if what they say is an obvious lie.
There definitely is. That each man should be free to follow his conscience. That the individual is worthwhile. That men are the masters of their destinies.
What,again?
I'm thankful God never changes His account of creation.
Doesn't that make Him more credible?
To Darwin it sure was. He believed in all that garbage he said. He believed that it should be implemented in the laws of the land. He believed that the world would be better off by it:
" Man scans with scrupulous care the character and pedigree of his horses, cattle, and dogs before he matches them; but when he comes to his own marriage he rarely, or never, takes any such care. He is impelled by nearly the same motives as the lower animals, when they are left to their own free choice, though he is in so far superior to them that he highly values mental charms and virtues. On the other hand he is strongly attracted by mere wealth or rank. Yet he might by selection do something not only for the bodily constitution and frame of his offspring, but for their intellectual and moral qualities. Both sexes ought to refrain from marriage if they are in any marked degree inferior in body or mind; but such hopes are Utopian and will never be even partially realised until the laws of inheritance are thoroughly known. Everyone does good service, who aids towards this end. When the principles of breeding and inheritance are better understood, we shall not hear ignorant members of our legislature rejecting with scorn a plan for ascertaining whether or not consanguineous marriages are injurious to man." Darwin, Descent of Man, Chapter 21.
"Man, like every other animal, has no doubt advanced to his present high condition through a struggle for existence consequent on his rapid multiplicaiton; and if he is to advance still higher he must remain subject to a severe struggle. Otherwise he would soon sink into indolence, and the more highly gifted men would not be more successful in the battle of life than the less gifted. Hence our natural rate of increase, though leading to many and obvious evils, must not be greatly diminished by any means. There should be open competition for all men; and the most able should not be prevented by laws or customs from succeeding best and rearing the largest number of offspring." Darwin, Descent of Man, Chapter 21.
In man the frontal bone consists of a single piece, but in the embryo, and in children, and in almost all the lower mammals, it consists of two pieces separated by a distinct suture. ~~This suture occasionally persists more or less distinctly in man after maturity; and more frequently in ancient than in recent crania, especially, as Canestrini has observed, in those exhumed from the Drift, and belonging to the brachycephalic type. Here again he comes to the same nclusion as in the analogous case of the malar bones. In this, and other instances presently to be given, the cause of ancient races approaching the lower animals in certain characters more frequently than do the modern races, appears to be, that the latter stand at a somewhat greater distance in the long line of descent from their early semi-human progenitors. Darwin, Descent of Man, Chapter 2.
With savages, the weak in body or mind are soon eliminated; and those that survive commonly exhibit a vigorous state of health. We civilised men, on the other hand, do our utmost to check the process of elimination; we build asylums for the imbecile, the maimed, and the sick; we institute poor-laws; and our medical men exert their utmost skill to save the life of every one to the last moment. There is reason to believe that vaccination has preserved thousands, who from a weak constitution would formerly have succumbed to small-pox. Thus the weak members of civilised societies propagate their kind. No one who has attended to the breeding of domestic animals will doubt that this must be highly injurious to the race of man. It is surprising how soon a want of care, or care wrongly directed, leads to the degeneration of a domestic race; but excepting in the case of man himself, hardly any one is so ignorant as to allow his worst animals to breed.
Darwin, "The Descent of Man", Chapter V.
Have you evos never bothered to read his blather or do you agree with him?
Is the above an insult, or is it supposed to be an answer to the following?
To: exDemMom
In your example, your numbers indicated that the mutant, and only the mutant, was part of a breeding pair that produced 10 offspring, half of which inherited the mutation, as per my assumption 1 (sexual reproduction). However, your population size as a whole was increasing as if each individual was producing 10 offspring, as per my assumption 2 (asexual reproduction). Either every individual pairs up to produce offspring or every individual produces offspring asexually, in which case all the mutant's offspring are mutants. You cannot mix the two types of reproduction, as you did in your example.
You are correct, I was wrong. Now I understand my mistake. In sexual production we have a pair of organisms and in a stable population there will be two progeny from the organism with the mutant, which according to the laws of chance means that one of the two should carry the mutant gene. So the fate of a new mutation is not as awful as I thought it was.
However, that as you say " A trait which confers neither a survival advantage nor disadvantage remains in the population at a constant frequency" presents severe problems for the theory of evolution. For one thing, such a mutation will never spread through the population. This is necessary for it to be able to gain mutations which will turn it into a favorable mutation and give it the possibility of becoming widely adopted throughout the species.
There is another problem with such a new mutation not being able to spread. Even though it is true that a trait remains in the population at a constant frequency, this is only true when the sample is large. A new mutation has (in a constant size population) only one chance. That is why even such a pro-evolutionist site as TalkOrigins, and a pro-evolutionist author there is forced into the admission that:
Neutral alleles Most neutral alleles are lost soon after they appear. The average time (in generations) until loss of a neutral allele is 2(Ne/N) ln(2N) where N is the effective population size (the number of individuals contributing to the next generation's gene pool) and N is the total population size. Only a small percentage of alleles fix. Fixation is the process of an allele increasing to a frequency at or near one. The probability of a neutral allele fixing in a population is equal to its frequency. For a new mutant in a diploid population, this frequency is 1/2N.
From: Introduction to Evolutionary Biology
This may sound strange to many, but the originator of the theory of population genetics, Ronald A. Fisher in "The Genetical Theory of Natural Selection" (1958), admitted as much in spite of being such a devout evolutionist that he had originally tried to challenge the accuracy of Mendellian genetics. The reason for the loss of such a new gene is quite simply explained. With only one sample, at any time that the laws of chance do not even out, (in this example when neither of the two progeny carries the mutation), the mutation will die out. Since the mutation is not spreading, the likelihood of this happening is quite high. In fact, even a mutation with a slight degree of benefit would also be lost in this manner.
298 posted on 8/14/02 5:41 PM Pacific by gore3000
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Meaning that I am literally a walking textbook on the very subject matter on which you are trying to snow me.
I have no problem with that, thanks for the warning!
The fact is, genome project or not, we do not know how many genes or proteins are in humans. And the old adage that one gene = one protein is still pretty much true. When two different products come off a single gene, we call them isoforms--but still consider them the same protein.
While it is true that they are called isoforms, and that obviously they share much the same amino acid sequence, does not mean that this is not an extremely important discovery. It is also a fact that these different proteins are indeed necessary:
In vertebrates, the four A-actin isoforms present in various muscle cells and the B- and Y-actin isoforms present in nonmuscle cells differ at only four or five positions. Although these differences among isoforms seem minor, the isoforms have different functions: A-Actin is associated with contractile structures, and B-actin is at the front of the cell where actin filaments polymerize. From: The Actin Cytoskeleton
In this case the different forms have very important functions. So there is a need for this highly complicated system of alternative gene splicing.
This presents many problems to evolutionary theory of course. The change in one gene can affect several functions for one thing, it is hardly likely that it would be beneficial to all the gene's functions. Furthermore the existence of such multi-purpose genes makes it very unlikely that they could have arisen by random evolutionary means.
The further problem these multi-purpose genes show is that not only do many genes require a system to initiate, regulate, and stop protein production, but that they also need a system to tell them how to make different proteins. Surely developing such an intricate system is not the result of random chance. Surely, such a system is irreducibly complex and a sign of intelligent design.
325 posted on 8/14/02 7:21 PM Pacific by gore3000
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There is no higher probability than 1. Evolution, therefore, was inevitable.
Nice rhetoric, but totally deceitful. The real question is: what is the probability of constructing a piece of DNA some one million base pairs long at random?
Since you have given us so many testaments of your supposed learning, I cannot say that the statement that there exist self-replicating RNA molecules is a mistake. It needs to be called a blatant and humongous lie, and I am calling on you to prove you are not a liar.
That's a lot of believing going on there! However, the first supposed mammal, is just a lower jaw and some parts of a pasted up upper skull which is more like a jigsaw puzzle than anything else. In addition at over 200 million years old (supposedly) it is over a hundred million years away from the next definitely mammalian bones.
Well, should be expected from an evolutionist though, as Darwin's proof of the eyes evolving was if you have read through two hundred some pages of my absolute nonsense, you have to believe with me that these eyes evolved.
Total nonsense. To imply that a plant is as complex as a human is ridiculous. The reason men are more complex while having a smaller genome than some plants is that humans have very involved genomes which are able to reuse DNA in different ways, while most lower organisms cannot. Also, the junk is not junk at all. A Japanese puffer fish has just as many genes as humans and amazingly none of what you call junk DNA. The reason it is less complex than man is because what you incorrectly call junk and what real scientists call 'non coding DNA' is what enables humans to do so much more with their genes than a puffer fish.
Yeah, except the parts are not exactly the same from one organism to the next...
Of course not, because a higher organism requires different DNA. If it was exactly the same you would have the same species would you not? Guess, you must have been sick when that class was given.
Whoever may have tried to correct me, was certainly not you. All you do on these threads is insult people and bash Christianity. If evolution was not so totally phony and you were not so totally lame, you would not need to insult me and others who oppose evolution, you would just prove me wrong and go on, but you know very well that evolution is false so your only defense against the truth it to attack your opponents because after all:
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