Theory of Human Evolution Shattered?

[jankren]

Study Finds Twist In Human Evolution
By SETH BORENSTEIN, AP Science Writer



WASHINGTON - Surprising fossils dug up in Africa are creating messy kinks in the iconic straight line of human evolution with its knuckle-dragging ape and briefcase-carrying man.

The new research by famed paleontologist Meave Leakey in Kenya shows our family tree is more like a wayward bush with stubby branches, calling into question the evolution of our ancestors.

The old theory was that the first and oldest species in our family tree, Homo habilis, evolved into Homo erectus, which then became us, Homo sapiens. But those two earlier species lived side-by-side about 1.5 million years ago in parts of Kenya for at least half a million years, Leakey and colleagues report in a paper published in Thursday's journal Nature.

In 2000 Leakey found an old Homo erectus complete skull within walking distance of an upper jaw of the Homo habilis, and both dated from the same general time period. That makes it unlikely that one evolved from the other, researchers said.

It's the equivalent of finding that your grandmother and great-grandmother were sisters rather than mother-daughter, said study co-author Fred Spoor, a professor of evolutionary anatomy at the University College in London.

The two species lived near each other, but probably didn't interact with each other, each having their own "ecological niche," Spoor said. Homo habilis was likely more vegetarian and Homo erectus ate some meat, he said. Like chimps and apes, "they'd just avoid each other, they don't feel comfortable in each other's company," he said.

They have some still-undiscovered common ancestor that probably lived 2 million to 3 million years ago, a time that has not left much fossil record, Spoor said.

Overall what it paints for human evolution is a "chaotic kind of looking evolutionary tree rather than this heroic march that you see with the cartoons of an early ancestor evolving into some intermediate and eventually unto us," Spoor said in a phone interview from a field office of the Koobi Fora Research Project in northern Kenya.

That old evolutionary cartoon, while popular with the general public, keeps getting proven wrong and too simple, said Bill Kimbel, who praised the latest findings. He is science director of the Institute of Human Origins at Arizona State University and wasn't involved in the research team.

"The more we know, the more complex the story gets," he said. Scientists used to think Homo sapiens evolved from Neanderthals, he said, but now know that both species lived during the same time period and that we did not come from Neanderthals.

Now a similar discovery applies further back in time.

Leakey's team spent seven years analyzing the fossils before announcing their findings that it was time to redraw the family tree — and rethink other ideas about human evolutionary history, especially about our most immediate ancestor, Homo erectus.

Because the Homo erectus skull Leakey recovered was much smaller than others, scientists had to first prove that it was erectus and not another species nor a genetic freak. The jaw, probably from an 18- or 19-year-old female, was adult and showed no signs of any type of malformations or genetic mutations, Spoor said. The scientists also know it isn't Homo habilis from several distinct features on the jaw.

That caused researchers to re-examine the 30 other erectus skulls they have and the dozens of partial fossils. They realized that the females of that species are much smaller than the males — something different from modern man, but similar to other animals, said study co-author Susan Anton, a New York University anthropologist. Scientists hadn't looked carefully enough before to see that there was a distinct difference in males and females.

Difference in size between males and females seem to be related to monogamy, the researchers said. Primate species that have same-sized males and females, such as gibbons, tend to be more monogamous. Species that are not monogamous, such as gorillas and baboons, have much bigger males.

This suggests that our ancestor Homo erectus reproduced with multiple partners.

The Homo habilis jaw was dated at 1.44 million years ago. That is the youngest ever found from a species that scientists originally figured died off somewhere between 1.7 and 2 million years ago, Spoor said. It enabled scientists to say that the two species lived at the same time.

All the changes to human evolutionary thought should not be considered a weakness in the theory of evolution, Kimbel said. Rather, those are the predictable results of getting more evidence, asking smarter questions and forming better theories, he said.
http://news.yahoo.com/s/ap/20070808/...uman_evolution

A very interesting discovery indeed.

[-Conan the Barbarian-]

It didn't shatter the theory of evolution at all however....

[Blau&Gruen]

Homo Sapiens and Homo Neanderthalis have lived side by side for millenia across Europe and the Near East. One of my High School sport teachers was a direct descendant of Homo Neanderthalis.

[Gary88]

we've known eveolution was 'messy' as the article puts it for quite along time. i always love when creationists see evolution as amoeba---dinosaur---koala---monkey----aunt muriel

[Blau&Gruen]

amoeba=aunt muriel

There are other examples of a possible coexistence of hominides of different species. The longer of course these reaches back into the history of human evolution the more difficult they are to prove.

[LSJ]

All this find did was break the theory of human evolution, and require it to be repaired. There is nothing going against evolution, just the previous theory of which species developed into which to end as homo sapiens.

I'm sure we'll see this happen many times in the next century when they discover new variations of humanoids.

[Sétanta]

No, it just makes the theory more complex.

[Gary88]

No, it just makes the theory more complex.

accurate not complex

[Blau&Gruen]

The Wiki article "Human Evolution" has a board showing the distribution of hominides-groups through time. The assumed overlapping of Habilis and Erectus is not thematized in that graphic.

http://en.wikipedia.org/wiki/Human_evolution

[MasterOfNone]

As I understand it, the evidence for the various supposed stages of human evolution simply do not exist. From skeletons deformed by arthritis to bones that proved later to not even be an ape's let alone human (they were a pig's I believe) the evolutionists have just clung from straw to straw.

Evolutionary theory just does not, imho, fit the evidence.

[ajm317]

As I understand it, the evidence for the various supposed stages of human evolution simply do not exist. From skeletons deformed by arthritis to bones that proved later to not even be an ape's let alone human (they were a pig's I believe) the evolutionists have just clung from straw to straw.

Evolutionary theory just does not, imho, fit the evidence.

Ah, it's always great to have the opinion of an expert.

I love it when creationists extrapolate a few mistakes to the conclusion that every thing about evolution is wrong. Despite what your propaganda tells you not all the fossil evidence is so easily dismissed as arthritis and pig bones.

[Dracula]

As I understand it, the evidence for the various supposed stages of human evolution simply do not exist. From skeletons deformed by arthritis to bones that proved later to not even be an ape's let alone human (they were a pig's I believe) the evolutionists have just clung from straw to straw.

Evolutionary theory just does not, imho, fit the evidence.

There is no evidence for the evolution .It is not a theory but a hypothesis . I wonder when will people find that all these Homos were just monkeys and men did not come at all from them but were separate species . Not that I praise creationism but the truth seems incompatible with monkey's skulls and stuff of the sort .
I heard recently to inplant a liver in human you may mainly from pigs not from apes .Will it be interpreted like we came from pigs .Rather likely looking at some people's morals . However I hope not .

[eventhorizen]

The Wiki article "Human Evolution" has a board showing the distribution of hominides-groups through time. The assumed overlapping of Habilis and Erectus is not thematized in that graphic.

http://en.wikipedia.org/wiki/Human_evolution

That is because Homo Hablis evolved into Homo Erectus, and the divide between the two species is meant to show the time when the majority of the species is dominant Erectus traits, rather than alluding to two coexisting species.

This is what happens when you try to document something complex in a simple graph, rather than writing and reading text. Here is a better graph from the same page. http://upload.wikimedia.org/wikipedi...utionchart.jpg

Showing an overlap of Erectus and Hablis would present the concept that there were two distinct species of hominid coexisting, when the reality was a single ancestor species radiating and evolving, with Erectus traits becoming the dominant evolutionary product, differing from original Hablis traits enough to warrent a reclassification of the offspring of Hablis.

The Hablis traits replaced by Erectus traits, smaller brains etc. would have certainly still existed in Erectus, but would have now been genetic faults and genetic disadvantage compared to the new genetic majority, and would have resulted in 'pure Hablis' offspring within the Erectus species suffering from a distinct competitional disadvantage in feeding, mating, social behaviour, and this would have lead to their eventual dissapearance from the genetic stock of the now different enough to warrent reclassification species.

This took time, obviously, and was closer to the filtering of a dye through a body of water, than the complete divergance of a new unique species from Hablis parents. In truth that graph should not consist of broken lines, but it is obviously done so to draw distinction to time rather than accurate presentation of evolutionary change.

Actually, there is a LOT of interpretation of evidence. That is true. Data does not really speak for itself. It is interpreted.

Data does speak for itself. It is the theory of how it all fits together that is the interpretation, and untill you come up with a better answer to fit the data together, this theory remains the best current explanation. And as you well know, theories themselves evolve to better explain observation.

As a side note, evolution itself cannot be argued against.

All the changes to human evolutionary thought should not be considered a weakness in the theory of evolution, Kimbel said. Rather, those are the predictable results of getting more evidence, asking smarter questions and forming better theories, he said.

[Blau&Gruen]

Showing an overlap of Erectus and Hablis would present the concept that there were two distinct species of hominid coexisting, when the reality was a single ancestor species radiating and evolving, with Erectus traits becoming the dominant evolutionary product, differing from original Hablis traits enough to warrent a reclassification of the offspring of Hablis.

Is Homo Ergaster seen as an archaic variant of Erectus?

[Simetrical]

As I understand it, the evidence for the various supposed stages of human evolution simply do not exist. From skeletons deformed by arthritis to bones that proved later to not even be an ape's let alone human (they were a pig's I believe) the evolutionists have just clung from straw to straw.

Evolutionary theory just does not, imho, fit the evidence.

Evolutionary theory (in particular, the single-origin hypothesis) makes a large number of predictions that are borne out by research results on a daily basis. Look here for a long, detailed explanation of many of these predictions. Some examples:

1. If you say that X and Y evolved separately from Z, that predicts that intermediate fossils may or may not be found between X and Z or Y and Z: fossil formation is extremely rare and there might just not have been any fossils formed, but it's possible. But, more importantly, that predicts that fossils will absolutely never be found that are intermediate between X and Y. There can't be: they evolved separately.
   
   Take a single concrete example (of which there are many others). It is believed that birds evolved from reptiles, and mammals separately evolved from reptiles. Thus we can expect to possibly find fossils intermediate in form between reptiles and birds, or between reptiles and mammals, and in fact we have. But the theory predicts that we will never, ever find any fossils intermediate between mammals and birds, and indeed, we have not. If we ever did, that would be a serious blow: it would require improbable explanations such as long-independent lineages merging. New fossils are dug up every day, and each and every one tests this prediction of the theory of evolution. It has not yet been violated.
2. Evolution predicts that if X evolves from Y, X may or may not retain some vestigial characteristics of Y that do nothing but simply were never selected against, or are tied up in useful genes, and so remain. On the other hand, it predicts that X will absolutely never have such vestigial characteristics from Z, which it did not evolve from. Once again, species are fitted into a neat tree, with branches splitting but never recombining. This can be easily falsified, of course. I'll just give up and quote examples from here:
   

   No organism can have a vestigial structure that was not previously functional in one of its ancestors. Thus, for each species, the standard phylogenetic tree makes a huge number of predictions about vestigial characters that are allowed and those that are impossible for any given species.
   
   Shared derived characters and molecular sequence data, not vestigial characters, determine the phylogeny and the characteristics of predicted common ancestors. Thus, if common descent is false, vestigial characters very possibly could lack an evolutionary explanation. For example, whales are classified as mammals according to many criteria, such as having mammary glands, a placenta, one bone in the lower jaw, etc. Snakes likewise are classified as reptiles by several other derived features. However, it is theoretically possible that snakes or whales could have been classified as fish (as Linnaeus originally did). If this were the case, the vestigial legs of whales or the vestigial pelvises of snakes would make no sense evolutionarily and would be inconsistent with common descent.
   
   It follows, then, that we should never find vestigial nipples or a vestigial incus bone in any amphibians, birds, or reptiles. No mammals should be found with vestigial feathers. No primates should ever be found with vestigial horns or degenerate wings hidden underneath the skin of the back. We should never find any arthropods with vestigial backbones. Snakes may occasionally have vestigial legs or arms, but they should never be found with small, vestigial wings. Humans may have a vestigial caecum, since we are descendants of herbivorous mammals, but neither we nor any other primate can have a vestigial gizzard like that found in birds.

   Again, this is tested whenever we find a new species. Why should humans develop tails as embryos but not feathers or beaks? This is predicted by evolution: we evolved from animals with tails, but not from those with feathers or beaks. This kind of evidence, too, is tested every time the anatomy of a creature is newly examined. Before he even starts, the examiner knows what to expect as possible and what as impossible. What evolution deems possible is often found, and what it deems impossible is not.

I can only do a poor job of summarizing my link. It's very thorough and lays out no fewer than 29 things that evolution predicts. Something like intelligent design simply avoids explaining why living things are naturally classifiable using a tree structure (most things are not: rocks, say, cannot be hierarchically classified in any one natural way), why organisms in the distant past were simple and grew overall more complex over time until the recent past (why couldn't they have been the same throughout history, created in Eden just as today?), why all life shares the same details of its genetic mechanisms (why does UUU have to be phenylalanine? why can't it be alanine in some organisms, valine in others, . . .), etc., etc., etc. It makes no predictions and so is not scientific. Evolution has great explanatory power, and it makes numerous predictions that have been confirmed again and again. It is every bit a scientific theory.

Edit: The particular concern of this thread does not, of course, shatter evolutionary theory generally. I'll change the thread title to clarify.

[Gary88]

As I understand it, the evidence for the various supposed stages of human evolution simply do not exist. From skeletons deformed by arthritis to bones that proved later to not even be an ape's let alone human (they were a pig's I believe) the evolutionists have just clung from straw to straw.

Evolutionary theory just does not, imho, fit the evidence.

there is alot and i mean ALOT (museum labs full of the stuff) of fossil evidence for evolution let alone the masses of genetic evidence

[MasterOfNone]

Actually, there is a LOT of interpretation of evidence. That is true. Data does not really speak for itself. It is interpreted.

[Gary88]

sigh Ken Miller FTW






if you dont watch them dont ask me about them

[MasterOfNone]

Interpretation, as I said. That some cannot see it as such is because they do not wish to have an open mind. No pancake is so thin that it only has one side. There are powerful and cogent arguments out there for many - and quite contradictory - interpretations.

[Gary88]

Interpretation, as I said. That some cannot see it as such is because they do not wish to have an open mind. No pancake is so thin that it only has one side. There are powerful and cogent arguments out there for many - and quite contradictory - interpretations.

their are neither powerful nor cogent arguments for something like creationism

in the words of David Attenbourough "evolution has masses of physical evidence from the real world, Intelligent design has a manuscript, nothing based out here, in the real world"