Interesting to say the least - Rocket River http://news.yahoo.com/s/ap/20070808/ap_on_sc/human_evolution ------------------------------------------------------------------------- Fossils challenge old evoluton theory WASHINGTON - Surprising research based on two African fossils suggests our family tree is more like a wayward bush with stubby branches, challenging what had been common thinking on how early humans evolved. The discovery by Meave Leakey, a member of a famous family of paleontologists, shows that two species of early human ancestors lived at the same time in Kenya. That pokes holes in the chief theory of man's early evolution — that one of those species evolved from the other. And it further discredits that iconic illustration of human evolution that begins with a knuckle-dragging ape and ends with a briefcase-carrying man. The old theory is that the first and oldest species in our family tree, Homo habilis, evolved into Homo erectus, which then became human, Homo sapiens. But Leakey's find suggests 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. She and her research colleagues report the discovery in a paper published in Thursday's journal Nature. The paper is based on fossilized bones found in 2000. The complete skull of Homo erectus was found within walking distance of an upper jaw of Homo habilis, and both dated from the same general time period. That makes it unlikely that Homo erectus evolved from Homo habilis, 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, each having its own "ecological niche," Spoor said. Homo habilis was likely more vegetarian while 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. There remains 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, is just too simple and keeps getting revised, 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 part of the Leakey 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 we 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. Susan Anton, a New York University anthropologist and co-author of the Leakey work, said she expects anti-evolution proponents to seize on the new research, but said it would be a mistake to try to use the new work to show flaws in evolution theory. "This is not questioning the idea at all of evolution; it is refining some of the specific points," Anton said. "This is a great example of what science does and religion doesn't do. It's a continous self-testing process." For the past few years there has been growing doubt and debate about whether Homo habilis evolved into Homo erectus. One of the major proponents of the more linear, or ladder-like evolution that this evidence weakens, called Leakey's findings important, but he wasn't ready to concede defeat. Dr. Bernard Wood, a surgeon-turned-professor of human origins at George Washington University, said in an e-mail Wednesday that "this is only a skirmish in the protracted 'war' between the people who like a bushy interpretation and those who like a more ladder-like interpretation of early human evolution." Leakey's team spent seven years analyzing the fossils before announcing it was time to redraw the family tree — and rethink other ideas about human evolutionary history. That's especially true of 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 malformation 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 Anton. 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. Primates 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 Homo erectus and Homo habilis lived at the same time.
If the earlier evolution theories are not correct, new evidence will result in corrections. Science is based on logic and evidence. There could also be other theories that might explain this,this happens all the time in scientific areas. Current science do not claim to be 100% accurate, it just tries to expalin nature as best as we can under current knowledge.
I hope they emphasize the word "theory" in the "theory of evolution" in schools more often. I know my school certainly didn't.
Yeah, and they better do that for the "theory" of gravity too. And the theory of electricity. And the theory of atomic physics. And... It might be more prudent that they educate students on what a scientific "theory" really connotates *cough*. But hey, that's a lot of work.
well yes, thats exactly what I'm saying. teach them what a theory is and emphasize that evolution is a theory. it'll stand up to scrutiny if it's a correct theory. I certainly think its a correct theory. I just don't think you should de-emphasize the theory part, otherwise evolutionists look like morons when stuff like this pops up.
Yeah that is exactly what this article is about.... There is a difference between in house squabbles among biological anthropologists regarding a specific taxonomy and creationist/ID garbage.
seems like it to me evolution is a theory which is subject to change. But I wonder how many people treat the theory on the same level as gravity? Anyway, I'm not challenging the theory. Like I said, I happen to think it's the correct one
Again, this article has nothing to do with the validity of the overall theory of evolution - rather it is is presumed to be correct and serves as a background for the dispute about where homo habilis fits in the family tree. As far as gravity - you missed rhadamantheus' point entirely. Gravity is equally as poorly understood (and as full of holes) as evolutionary biology in many respects. Yet you don't fin people agitating about it being just a 'theory'......
hmm, I'm just pointing out that there are things about a theory which are subject to change which is why it's a theory. And that if people treat it as if it's 100% correct all the time, you need to remind them otherwise.
It is not 100% accurate but it is by far the best foundation theory in the area of biological science.
I agree and the article and thread title are somewhat misleading. The new findings don't challenge the theory of evolution as a whole just a small segment of human evolution. Now if they found a homo habilis skull dating back 100 million years ago that might challenge the theory of evolution as a whole. Gravity is much less understood than evolution.
Um, really? Is the writer an anthropologist? I don't see the "discredit," and it seems written, in a sensational and perhaps misleading way, to incite the anti-evolution crowd. So, the iconic illustration needs two parallel intermediate steps, maybe. That would be a big deal because... ?
For anything visible to the naked eye, we understand the effect of gravity (if not necessarily the mechanism) very well. When was the last time you saw a person just float away off the planet?
He's AP's science writer, I doubt he should be considered a hack or have to prove his pedigree to anyone.
And the link between humans and other primates is also visible to the naked eye - as are any number of experiments involving natural selection with microorganisms.
It's not the evolutionists that look like idiots. Scientists previously thought that two species didn't live next with each other, now they might think that they did. This doesn't discredit evolution at all. It just reworks our family tree and leaves more questions. The only people crying about the "theory" part in evolution emphasized are fundamentalist Christians. Nobody else cares. Do we have to do the same outcry for Einstein's theory of relativity? Why are they not as concerned about that? It's because it doesn't challenge their religious world view. The word theory has a number of distinct meanings in different fields of knowledge, depending on their methodologies and the context of discussion. In common usage, people often use the word theory to signify a conjecture, an opinion, or a speculation. In this usage, a theory is not necessarily based on facts; in other words, it is not required to be consistent with true descriptions of reality. True descriptions of reality are more reflectively understood as statements which would be true independently of what people think about them. In this usage, the word is synonymous with hypothesis. In science, a theory is a mathematical or logical explanation, or a testable model of the manner of interaction of a set of natural phenomena, capable of predicting future occurrences or observations of the same kind, and capable of being tested through experiment or otherwise falsified through empirical observation. It follows from this that for scientists "theory" and "fact" do not necessarily stand in opposition. For example, it is a fact that an apple dropped on earth has been observed to fall towards the center of the planet, and the theories commonly used to describe and explain this behaviour are Newton's theory of universal gravitation (see also gravitation), and general relativity. http://en.wikipedia.org/wiki/Theory
