Why is the hominid 'Lucy' just accepted to be a human remain and not just a monkey skull?

Question

re: Lucy (http://news.yahoo.com/s/afp/20060920/sc_afp/ethiopiascience_060920143923;_ylt=AhdcifqRUE9yNgkEkMS67.MTO7gF;_ylu=X3oDMTA5bGVna3NhBHNlYwNzc3JlbA--

I try to keep an open mind with the evolution issue, and there's some fascinating stuff to it. But when we are talking about one skull from a supposed 3.2 million years ago, isn't is, I dunno, a little unsafe for the scientists to just openly state "...she is the origin of mankind"?

I mean, we're talking about a really old skull, that might be a human descendent.... or might just be a monkey's skull. Isn't there a LOT of theorizing and guesswork here, a lot of which could be very wrong? (considering the huge gap in time?)

I'm just not sold, but I'm not weighing in one way or the other. Reading this article, and isn't it somewhat dangerous to just accept that "this is how it happened" and not just leave it in the realm of conjecture? (e.g. "what if...")?

Answer 1

Lucy was not "just accepted" to be a human. She was never called a human. She was a hominid, but she was neither human, nor ape. She had some traits of both. The clear facts of the different characteristics of her bones indicated that she should be classified as a hominid, and not as a modern human, ape, or monkey. To say that in the face of evidence, something is "just accepted" is like saying that the jurists in Jeffrey Dahmer's trial "just accepted" that he was guilty. No. There was evidence, and it was carefully considered.

How do we know Lucy was a hominid?
The term hominid refers to a member of the zoological family Hominidae. Hominidae encompasses all species originating after the human/African ape ancestral split, leading to and including all species of Australopithecus and Homo. While these species differ in many ways, hominids share a suite of characteristics which define them as a group. The most conspicuous of these traits is bipedal locomotion, or walking upright.

How do we know Lucy walked upright?
As in a modern human's skeleton, Lucy's bones are rife with evidence clearly pointing to bipedality. Her distal femur shows several traits unique to bipedality. The shaft is angled relative to the condyles (knee joint surfaces) which allows bipeds to balance on one leg at a time during locomotion. There is a prominent patellar lip to keep the patella (knee cap) from dislocating due to this angle. Her condyles are large, and are thus adapted to handling the added weight which results from shifting from four limbs to two. The pelvis exhibits a number of adaptations to bipedality. The entire structure has been remodeled to accommodate an upright stance and the need to balance the trunk on only one limb with each stride. The talus, in her ankle, shows evidence for a convergent big toe, sacrificing manipulative abilities for efficiency in bipedal locomotion. The vertebrae show evidence of the spinal curvatures necessitated by a permanent upright stance.

(This evidence of walking upright clearly indicates that Lucy could NOT have been a monkey or an ape, because the skeletal factors that point this out are not found in chimps. Also, Lucy's teeth were clearly different from any monkey or ape, having had reduced canines and molars.)

How old was she when she died?
There are several indicators which give a fair idea of her age. Her third molars ("wisdom teeth") are erupted and slightly worn, indicating that she was fully adult. All the ends of her bones had fused and her cranial sutures had closed, indicating completed skeletal development. Her vertebrae show signs of degenerative disease, but this is not always associated with older age. All these indicators, when taken together, suggest that she was a young, but fully mature, adult when she died.

How old is Lucy?
The hominid-bearing sediments in the Hadar formation are divided into three members. Lucy was found in the highest of these -- the Kada Hadar, or KH -- member. While fossils cannot be dated directly, the deposits in which they are found sometimes contain volcanic flows and ashes, which can now be dated with the 40Ar/39Ar (Argon-Argon) dating technique. Armed with these dates and bolstered by paleomagnetic, paleontological, and sedimentological studies, researchers can place fossils into a dated framework with accuracy and precision. Lucy is dated to just less than 3.18 million years old.

(It is quite telling how anti-evolutionists and creationists will mention things like the unknown farmer who buried a pig's skull and claimed to find a human skull, then then claim that scientists declared it to be thousands or hundreds of thousands of years old NEVER BOTHER TO MENTION THEIR SOURCE!!!)

As of 1999, there were fossils of about 150 Homo erectus individuals, 90 Australopithecus robustus, 150 Australopithecus afarensis, 500 Neanderthals, and more (Handprint 1999). Foley (2004) lists some of the more prominent fossils. Since Lucy's discovery in 1974, a total of 300 other Australopithecus afarensis fossils have been found, helping to form a more complete picture of what Lucy would have looked like. There is evidence that Lucy and other hominids of her species (A. aferensis) may have been partially arboreal. Rather than contradicting that Australopithecus afarensis was an ape, it shows that she was a transitional species (Those pesky little critters that creationists say don't exist), because so many other features that Australopithecus afarensis shares with humans are not found in apes and monkeys.

If Lucy was still the only specimen of Australopithecus afarensis to have ever been found, it would indeed be mostly conjecture to say that she was a human relation, but it would still be accurate, not guesswork, to say that she was not a monkey or ape, and was a non-human hominid. More than just her skull was found. Lucy's skeleten was about 40% complete.

Last, Lucy's place among human origins is still hotly debated among scientists. Biologists do not think Lucy as an individual was likely a direct ancestor of anyone. This cannot be determined from fossils. Lucy and her species is not the oldest known fossil with human characteristics, and has never been claimed to be the first origin of humans. It is only figured that she fits somewhere as a realtive of humans, because of shared traits. Other, older hominids and ancient species that were neither totally ape nor totally human have been found. It is a fact that the younger the species of hominid, the more human characteristcs appear.

Hope this helps. It was a very good, reasonable question, and I am NOT being sarcastic with you. Thanks.

Answer 2

A pig's skull? lol. Anyway...

The first thing is that the news media often gets things slightly wrong (like our friend up the page) - the journalist who wrote this is unlikely to be an expert in physical anthropology - a simple, wow! sounding article is the name of the game and what was really said can get distorted, innocently enough.

The second thing is the history of life is a branching bush, not a straight line. What this article actually means to say is that most experts these days consider 'Lucy' to belong to a different branch than ourselves. The original hypothesis that her species was our ancestor has been disproven (largely). This happens a lot in science. And is partly because of all the other fossils found, of other hominid species.

But sure, as a paleontologist (of another branch of life for which there is a much richer fossil record), I agree that is seems the hominid people tend to extrapolate a bit far sometimes as to some of the specifics. But I think there is enough of a fossil record (not to mention genetics) to show that we did evolve from 'apes', if we don't know specifically along which path.

Answer 3

Evolution is a Theory ....... JUST LIKE GRAVITY !!! A Scientific Theory

—Synonyms 1.
Theory, hypothesis are used in non-technical contexts to mean an untested idea or opinion. A theory in technical use is a more or less verified or established explanation accounting for known facts or phenomena: the theory of relativity.

A hypothesis is a conjecture put forth as a possible explanation of phenomena or relations, which serves as a basis of argument or experimentation to reach the truth: This idea is only a hypothesis.

Most people ae confused by mass media as to what a theory really is. Those whom have a political or religious agenda tend to consolidate all theories into the second statement - a hypothesis or conjecture. Those whom believe that science attempts to prove a fact based upon repeatable observable evidence understand the first statement. In this way, Gravity cannot be seen but it's effects can be measured and the measures can be repeated by other scientists from around the world, not just scientists from a certain country or religious outlook. Therefore, when we think about scientific theory we believe that it is reliable until more hard evidence to the contrary is presented and the paradigm changes.

Basically it is what is provable based on evidence versus what is conjecture. Therefore, Evolution would be scientific theory and Creationism whould be Hypothesis or Conjecture.

Answer 4

You have a point to an extent, but you're not getting all the info from this article. There are quite a few fascinating Discovery shows, textbooks, and various other information resources revolving around Lucy. There are certain key features from the skull that differentiate it from that of true apes. Lucy was advanced enough not to be considered an ape anymore, thus considered a really, really early hominid. The point I'm going to agree with you on is the fact that anthropology does take things a little too far sometimes. They like to make up scenarios based on not enough evidence (for instance, in the Middle Americas where they dug up a pit of human bones with a log bridge across it, a hat, and a stick, and just assumed that it was a pit in which they battled to the death wearing the hat and hitting each other with sticks *rolls eyes*). The thing is, you have to start with a theory. It is often proven wrong later on, much with the original skeletal reconstruction of the iguanadon. But you have to have something to present when you spend thousands of dollars on a research dig, so you have to come up with a scenario. *shrug* That paves the way for better understanding in the future.

Answer 5

I think you meant to say that Lucy might be a human ancestor, not descendent. And it is true that A. afarensis may not be a direct human ancestor, after all, but it clearly represents something much more highly evolved than any apes that are known today. So even if it is "just a monkey skull," it represents evolution from earlier apes, even if it wasn't a successful evolution.

Answer 6

Even if it is just some "monkey skull" it is a link to the past. Some believe that Lucy is one of the missing links to connect the evolution from monkeys to humans. There is a lot of guess work but when you think about it there is a lot of proof that she is our link to evolution.

Answer 7

Lucy is believed to be a specimen of Australopithecus afarensis. She was not human, nor was she monkey. It is believed that A. afarensis could possibly be one of the ancestors of modern humans, but not a human herself. She was however an ape. Because we too are apes. Now as to your reference about her "being a person." That is a vague and very subjective term. What do you define as "being a person?" Biologically, no she was not human. Does that mean she wasn't a person? Its believed that her kind could reason, they could to a minor extend possibly make tools (very very simplistic tools, but the reasoning was there to do so). She probably had emotions and was a part of her community. Its even plausible that her kind had a very primitive, simplistic form of culture by the evidence that modern apes have shown signs of culture. Culture being defined as learned, transmitted behavior. So was she a person? I would think so.

Answer 8

In the 1930's a farmer in Britian told people he found a skull that was human and the scientist did testing on it and said it was thousand of years old and it was from early man. The farmer had killed a pig burried the skull and left it for a few years then told everyone that he found it. Fifteen years later he told the truth about the skull and the scientist had egg on their faces again.
Even with carbon dating they still can't come up with alot of facts on the "theory of evolution" so why is this skull any different for the rest? It isn't but those who try to say that their theory of evolution is fact still can't prove it as so.

Answer 9

It's not guess work...for anthropologists it's not difficult to tell the difference between a monkey skull and a human skull...for we cell biologists and laypeople its impossible and i would look at the thing and say "how do we know it's not just a monkey?"

But I didn't goto school for 20 years and study head shapes...i went and studied cells...

Answer 10

"Lucy" was more than just a skull. It was one of the most complete pre- human ancestor skeletons ever found, and as such can clearly be distinguished from a monkey, as it is evident that she walked up right.