MORE ABOUT ANCIENT SKIN
Eric writes...
This is about your answer to me, the one about the dinosaurs having hair. I was not only talking about dinosaurs, what about hominids? Have we found fossilized skin of Australopithecus africanus? Or even Homo erectus? How do we know their bodies were covered in hair? And why is Homo neanderthalensis always depicted without hairy bodies?
Well, Eric, I'm in a bit over my head here. Yours is a fairly technical question in a science that could include anthropology, paleontology, geology, anatomy, physiology, and archeology, but I'll give it a shot.
First of all, don't confuse theory with fact. "How do we know their bodies were covered in hair?" implies fact. Much of what is "known" in this science is theory. They take information from fossils compare it to anatomy and physiology, take into consideration the environment they lived in and extrapolate their theory.
The BBC ran a great series called "Walking with Cavemen". On their web site, they give a description of different hominids and then give the evidence to support that. An example would be the description and evidence about Homo ergaster:
DESCRIPTION
Homo ergaster was tall and muscular. Slim hips and long legs enabled this species to walk long distances. Their skin was smooth to cool themselves through sweating, meaning they no longer had to pant to keep cool.
Homo ergaster probably obtained food by scavenging or by chasing animals across the Savannah until they died from exhaustion.
This species was amongst the first to leave Africa and colonize other continents. After ergaster leaves Africa, it becomes known as Homo erectus.
In Asia, Homo erectus lived in the bamboo forests and may have made tools such as staffs and spears from this strong, versatile material.
EVIDENCE
The structure of Homo ergaster's facial bones suggests they had a human-like nose with downward pointing nostrils. This allowed them to add moisture to exhaled air, useful for an active species roaming through dry, open terrain.
Animal bones from ergaster sites have been found etched with the characteristic marks of stone tools used for butchery.
Several Homo ergaster fossils have been discovered in the Lake Turkana region of Northern Kenya, including a near complete skeleton known as 'Nariokotome Boy'.
Homo erectus fossils have been found all over Asia, from Zhoukoudien in China to Sangiran on the island of Java, Indonesia.
Now remember, this is a television show that tries to explain complicated science to the same people who (like me) watch the Family Guy, so you know it is at best a simplistic explanation. Now compare that to the description given by www.archaeologyinfo.com, which is more complex but is still geared to teaching the amateur. I won't quote it here as it is fairy long, complicated, and technical, but it uses many disciplines of science to come to a somewhat similar but somewhat different conclusion.
In any case, they have also looked at their physiology and environment and extrapolated their appearance and lifestyle.
Remember, paleoanthropology is a rapidly evolving science. When I was young, we learned that dinosaurs were slow, lumbering beasts related to lizards that died out over millions of years due to long term climatic changes. Just one view of Jurassic Park, and you will see that dinosaurs are now depicted as dynamic, fast and cunning. They are now related to birds and were wiped out by one big blast from a celestial object. This is a field of constantly conflicting theories and great debate. By the time you are my age, when the BBC produces an updated series of walking with cavemen, you will certainly find a lot of what we "know" now has changed.
So, as I re-read this, it looks like I really didn't answer your question and I should have stopped with "This is way over my head", but how much fun would that have been?
posted by Ask Jim... @ 9:51 AM
5 comments
5 Comments:
Say there, Jim!
Here's the deal. It looks like the St. Louis Cardinals are playing the Houston Astros in the NLCS. How many times have these teams met in the post-season, and what have been the results in the past? In terms of competitive advantages, what do they got that we ain't got, and what do we got that they ain't got?
I guess I would love to "Ask Jim" a question, but I have no idea how- I'd rather not just leave it in the comments box, but I have searched endlessly to no avail. Help!
..and, of course, now I've made a fool of myself, as it looks like you've gotten other questions in the comments...le sigh. Answered my own question!
Hi, Jim, I came across this blog while surfing. I thought I'd take a moment to address the question as it is and make a science comment as well. You bemoaned not feeling qualified; I have an anthropology degree so I'll lend you a hand.
The question asks specifically about whether early hominids, or pre-modern humans, or the Neandertal, had body hair. He's also asking about the depictions of these primates, and I would tell him to ignore those. Artist's interpretations, and makeup on real humans, have nothing to do with what researchers actually think.
Of course, all primates have body hair. Humans are hairy; simply thinly so. But the question was asking about three different species.
These three are spread across very different times. Only Neandertal is coincident with modern humans; actually, they predate humans in terms of evolutionary splitting. A. Africanus was closer to the split from other primates, about three million years ago. They are so close in morphology and time to chimpanzees that there is no reason to assume they are not covered in hair.
Neandertals appeared just over a hundred thousand years ago. Much more recently. How hairy were they? Honestly, we can't say. But we do know they clothed themselves, in addition to living in Europe during an ice age. It is likely they were less hairy than great apes.
After all, they are related to Homo Erectus, which is considered a pre-modern human in some circles. This specie was on the scene before Neandertal but much later than A. Africanus, about two m.y.a. Erectus, behaviourally and intellectually, does not compare to the Neandertals. They controlled fire, and only made very simple stone tools. Most were tall and thin; and as for hairiness, they likely were not. There is little migration to cold regions, and their adaptation to heat (tallness and thiness) would not make sense against a hairy body.
However, we are talking about geographically influenced variation; so a more sound answer might be that some Neandertals and H. Erectus groups were more or less hairier than others.
Now my science comment. When scientists, especially physicists, use the word "theory," you may take them as saying "fact." ((Unless we're discussing Superstring Theory, but that's another bone of contention I won't go into.)) Hypothesis are negatively formulated statements which are compared against evidence. According to support of evidence, they are modified until useful as propositional statements. These are incorporated into a larger philosophical body called the "Theory." A theory, in science, is not a estimation or guess. It is the closest approximation to fact ((assuming, of course, extant objective reality)) as science has come.
So I apologize for directly contradicting you, but 'confusing' fact with theory is the correct thing to do. What is controvertible is the quality and nature of evidence, a question well addressed by the time scientists use the word 'theory.'
Also, 'their' physiology is their appearence; and we do not know about their lifestyle per se, but we can know a few things about their behaviour. 'Behaviour,' in this context, is a scientific term.
I like your illustration of our changing knowledge in paleontology as a generalization of change in science. Though, to avoid confusion, while paleontology and paleoanthropology necessarily share many methodologies, one is a subset of zoology and the other anthropology.
I'll come back to this page later, in case this comment stimulates responses.
Nice blogg thanks for posting
Post a Comment
<< Home