Kimbel is not the only paleoanthropologist who thinks the new fossils belong in Homo instead of Australopithecus. Susan Antón of New York University observes that characteristics of the teeth, in particular, align them with our genus. But exactly how the skeletons relate to known Homo species is difficult to establish given the paucity of early Homo remains. "In many cases we don't know what some elements look like at all in some taxa," she says. The absence of any H. habilis hip bones to compare to A. sediba's is one such example. Antón suspects that A. sediba may be a dead-end branch of Homo, rather than an ancestor of later species such as H. erectus.
The level of disagreement about how to classify the Malapa fossils is perhaps to be expected, because the closer paleontologists get to the transition between Australopithecus and Homo, the harder it is going to be to determine which side of the divide a specimen falls on. Either way, the fossils illuminate a very mysterious chapter of human evolution. "They are going to be a remarkable window, a time machine of morphology into the evolutionary processes and evolutionary stresses that were going on at that period between 1.8 and 2 million years ago," Berger said at a press teleconference on April 7.
For instance, the combination of primitive and derived traits evident in A. sediba shows that different parts of the body were changing at different times during this phase of human evolution—the legs changed before the arms; the pelvis changed before the brain.
"A. sediba does give intriguing insights into the co-expression of traits associated with Homo and Australopithecus," remarks Fred Spoor of the Max Planck Institute for Evolutionary Anthropology in Leipzig. He observes that whereas it has Australopithecus-like brain size and molar shape, it calls to mind Homo in its brain case shape and molar size. These traits of A. sediba show that "brain size and certain features of the brain case are not necessarily linked, and molar size and morphology and not necessarily linked either."
That A. sediba exhibits such a mix of old and new traits both in the skull and throughout the body underscores to Jungers that the primitive features seen in australopithecines were not just evolutionary baggage from an ancestor that lived in the trees, as some scientists have argued. Rather, he says, such characteristics were major contributors to the success of the australopithecines, hence their persistence over millions of years. "It’s the ultimate loss [of these traits] with the emergence of Homo that begs explanation." In his view, selection for traits that enhanced our ability to run long distances can explain the transformation.
The Malapa skeletons seem unlikely to resolve the origin of Homo on their own. But clarification of how they should be classified—Australopithecus or Homo, side branch or main line—may not be far off: Berger told the press teleconference that since submitting his initial findings to Science, he has found at least two more hominin skeletons in the cave. He is currently excavating these, and has assembled a team of about 60 experts to analyze all of the material from the site in detail. Their to-do list includes determining whether the fossils might contain proteins or DNA suitable for sequencing, reconstructing the environment the hominins lived in, and studying the aging process and disease process in this ancient relative. Such efforts will no doubt reveal an incredibly detailed portrait of this newest addition to the human family.
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25 Comments
Add CommentAbsolutely fantastic! What an exciting find. I can't wait to hear more as the excavation and research continues.
Reply | Report Abuse | Link to thisNo DNA to analyze found?
Reply | Report Abuse | Link to thisDNA would be the bee's knees alright. But where ever these fossils fit in, to be sure, that bush by the stream is looking a whole lot thicker than ever before.
Reply | Report Abuse | Link to thisYour man Charles Darwin would be tickled pink.
I do so love the discovery of a new species, and a new transitional fossil-it gets so that it seems there's a new one every day.
What is it that those silly people say about transitional fossils? That there isn't any?
Though I continue to be disappointed at how inconclusive these 'finds' seem to be I, like most people, expect the next one to be the missing link that answers all questions.
Reply | Report Abuse | Link to thisBut quickly now my time draws near, so hurry on and nail the one that makes our time past clear...skause
This is no doubt an amazing find of a fossil and wherever it finally falls on the human or pro-human family tree when all the work and conclussions are worked-out this is absolutely fascinating.
Reply | Report Abuse | Link to thisWhen you say "transitional" , what do you mean exactly? Is this fossil species a direct mutation from another species? If so which one? What aspects of this fossil are considered transitional? I'm still learning biology so please be patient with me. Alex
Reply | Report Abuse | Link to thisskause: Don't look for one missing link to answer all questions. Evolution entails many links. In human evolution many links are no longer "missing", and in science every new discovery raises as many questions as it answers.
Reply | Report Abuse | Link to thisGreat stuff: it's good to be allowed to share in the excitement at these finds.
Reply | Report Abuse | Link to thisOn the interpretation: it seems that those are right who just keep saying ....the bush, the bush, the bush....
In that vein, unlike others above, I'm not confident that further finds will make everything clearer - they could make it worse.
The discovery of the SA fossil confirms exactly my speculation
Reply | Report Abuse | Link to thisabout the loss of estrus and the evolution of Man.
http://abcnews.go.com/Technology/ardi-fossil-brings-us-closer-common-ancestor-humans/story?id=8716359&page=1
The TEETH reveal that the creature lived in a promiscuous
chimp-style group, where the females mated with all males when the
females ovulated.
Then, when estrus was lost, with the "Eve", the way was opened
for monogamy and all other of the things which make us human,
including language.
http://blogs.myspace.com/index.cfm?fuseaction=blog.view&friendId=83327275&blogId=474343872
Amazing!
Comments?
Arne
...those long arms! Does that imply that he lived partly at least an arboreal lifestyle?
Reply | Report Abuse | Link to thisAbsolutely fantastic
Reply | Report Abuse | Link to thisIf we have to rethink the whole family tree every time a bone fragment is found maybe we should not turn speculation into theory.
Reply | Report Abuse | Link to thisI am prone to believe that there may have been numerous early hominids that evolved at the same time around 5 million years ago. Competition and adaptation continued to play a role until migration out of Africa. My theory doesn't explain what occurred to those that never left Africa and how early man continued to evolve in spite of never leaving the African environment???
Reply | Report Abuse | Link to thisTransitional. Everything is transitional. You are a transition from your parents and your parents parents. And your children and their children will be (or are) transitional to you.
Reply | Report Abuse | Link to thisOur new hominid is certainly a glimpse at a time when other uprights walked the plains of Africa; a glimpse like a snapshot of you when you were nine - a moment in time between eight and ten. this particular fossil may not represent a direct transition from an earlier ancestor to our own species, but it certainly would represent some form of collateral ancestry.
Much like your cousin is not in a direct line between your grandparents and you but is representative of the available gene pool of the time. Follow me?
This is why I prefer referring to the human bush. This fossil, no matter where it falls, makes the human bush much thicker than before. And it is likely to get thicker yet.
It's been said that our now robust history as told through the fossil record, makes it clear that we are not unlike other animals in this regard. We are not so far removed - singled out - from our ancestors.
It's great to know Where and When,Why and How to go is more interested..NIRVANA.....
Reply | Report Abuse | Link to thisHi, me again. I have another question for all you hardcore biologists out there: is there much(or any) skepticism among biologists about the Darwinian Evolution?
Reply | Report Abuse | Link to thisMaeve Leakey cracks me up. Her contempt for australopithicines in general, and how they can't touch Daddy's "Homo" lineage, never ceases to amaze me.
Reply | Report Abuse | Link to thisFacts and data, Ms. Leakey, facts and data. We should let the comparative anatomical studies do the talking, not your pet theories.
Hi Alex- I don't presume to speak for all biologists, but I think I can safely say that there is virtually no aspect of what Darwin described that is questioned. Evolution happened and is happening. The question isn't whether evolution occurs, it's how evolution occurs that we're exploring.
Reply | Report Abuse | Link to thiscoolmoss - That may be the established view, that genetically expressed features of identified species serve to functionally transition from one species to another.
Reply | Report Abuse | Link to thisHowever, I suggest that the concept of transitioning incorrectly infers a direction to evolution, i.e., as in 'hominids developed until they finally produced modern humans.' There is no destination or design objective to evolution, only the selection of characteristics, through survival and reproduction, that generally enhance survivability in the current environment.
The transitional view is based on a historical perspective of current species' characteristics. No future transitional development objective has been determined. If, for example, in the current environment lower intelligence promotes reproduction, intelligence levels will be reduced in the future.
This may seem like a trivial point, but I think the transitional view infers information that is not indicated by the evidence.
I think that the refutation of direction for evolution denies:
Reply | Report Abuse | Link to thisa. Ecology as a whole and
b. Culture and Society and its driving force in human evolution due to the breading and kinship vectors.
c. If Evolution has no direction -how do we explain the progress of complexity and organization that has and does continue on this Path.
Check Terrance McKenna on the conservation of novelty and the vortex at the end of time. sure.
After all , a chic is always following some guy and a guy is always following some chic and if you consider Evolution as breeding, as i do, then this is an evolutionary direction.
Reply | Report Abuse | Link to thisApparently they are using the term "transitional" to refer to any of the links between us and the earlier animal forms. If two species of humans evolved at the same point in time, one of the species may have evolved into yet another species, eventually evolving into modern humans. The other species may have died out without being in the chain between us and the earlier animals.
Reply | Report Abuse | Link to thisAll of these diverse hypotheses regarding the different "lines" leading to Homo Sapiens Sapiens are a sentient example of mankinds thinking in evolutionary terms.
Reply | Report Abuse | Link to thisOne's thought, or perhaps several, may end up being correct.
I personally think that all of our "cousins" discovered thus far, and those yet undiscovered but have yet to be, all take their place in the evolutionary tree.
If they were in fact a successful adapting species, they perhaps would have ended the line by stagnation, or being driven out or "one upped" by a more successful strain, or cousin, as is clearly still happeniong today.
Homo Sapiens Sapiens is not done evolving. Evolution is alive and flourishing. Certainly if still takes place today. If and when we take to space and the stars our spacer cousins will evolve dramatically to fit their new environment.
Tommybird,
Reply | Report Abuse | Link to this"I can safely say that there is virtually no aspect of what Darwin described that is questioned".
And that is the problem with biology. Genuine scientists are supposed to question their hypotheses. Biologists do not. In fact, they do not even properly define their hypotheses. Darwin's theory had two main hypotheses. The main one was that evolution is the result of branching descent from common origins. That is accepted by everyone except creationists and IDers.
Darwin's second hypothesis was his explanation of how evolution happens, Natural Selection. That was where Darwin was wrong.
If biologists applied the rigorous tests that scientists are supposed to apply, they would be shocked at the logical gaps in Darwin's explanation. If they carefully followed Darwin's argument, they would recognise that at its heart, Natural Selection relies on a little piece of magic. Briefly, Darwin decided that external conditions had no direct effect. What drove evolution were variations that improved the internal qualities of individuals and favoured them in a struggle for existence. Species (and individuals within species) became adapted to particular conditions not because of any effect from the conditions, but because they were favoured in those conditions. Sounds plausible, right? Read it for yourself in ch. 3 of Origin, but when you read it, remember that Darwin started from a rejection of the effect of external conditions. For more detail, check my blog:
http://ideasintuitionandthinking.com/blog
The crazy thing is that most biologists now accept that external conditions have major effect, but continue to use rules and assumptions that are based on Darwin's decision to reject the effect of external conditions.
If biologists reverse Darwin's decision, they have to reverse all the rules and assumptions that flowed from it.
Biologists apply the rule that there is no direction or purpose in evolution because, if you exclude the effect of external conditions, you exclude the only factor logically capable of providing direction or purpose. If you accept the effect of that factor, you accept that all major evolutionary change has purpose (survival in the prevailing conditions) and direction (adaptation to those conditions).
That change is not the result of selection by some imaginary entity or indefinable process. It is the result of the simple process of deselection of individuals unable to survive in those conditions.
I wonder just how much of the controversy (between researchers)each of these exciting new find brings is due to the competition for limited funding. Paleontology does not, after all, help develop new commercial shiny gadgets or drugs to help us through our dreary days. Perhaps the thrill of discovery that we all share could be increased if collaboration could somehow replace such competition.
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