H. erectus older than thought, new dating technique used Options

[vilnoori]

New Nature article discussing a new dating technique that pushes back the date of the the Beijing H. Erectus specimens to about 700 000 years ago. This underscores the importance of leaving the dirt on any BF bones you might find. It is very very important dirt!

http://www.nature.com/news/2009/090311/ful...s.2009.149.html

[wolftrax]

Actually this again stresses the importance of leaving fossils where they are found in situ. The tests weren't done on dirt from the fossil but were done at the exact locations and strata layer that the fossils were found in. This was only possible because the location and strata layer was properly documented in the first place.

If you find fossils and move them you are destroying any possibility of reliably dating the fossil.

[BobZenor]

Very cool fossil. That is very shortly after an extreme warm period where even the Greenland ice sheet melted. Some think that a new migration out of Africa likely happened about that time. Signs of fire were first observed in Europe about that time. Looking at that guy just superficially, it looks very ape like. It has pretty extreme prognathism or protruding jaws and a slanting forehead. I have heard people say this is supposed to be equivalent to our ancestor about that long ago but I find it hard to believe.

peking man fossil.

later heidelbergensis about 200,000 years later


Then you have this one of the same age found in Sangiran Java that also seems to look quite different.


Overall impression on incomplete partial skulls is probably not be the best way to gauge relationships, but the Peking man seems to have much more prognathism and looks much more apelike. The Chinese paleontologists commonly think it is an ancestor. That illustrates why bones are really bad for determining relationships and why I don't take what some paleontologists thinks about it as very conclusive. The zygomatic process or cheeks looks quite different if they are supposed to be the same species. The sangiran and peking look like they might be pretty close but even there the sangiran seems to have big eyes.


These are among the few and best erectus evidence. A tooth study showed there were likely two groups and a replacement just before that time. Floresiensis indicates there were at least two groups because they have features found in Australopithecus. Older than a million years old and the Asian erectus had larger teeth and smaller brains. It make me very skeptical of anyone who thinks he can place all or any particular erectus in a family tree. These are supposed the be the same erectus species even according to the tooth study. We will probably have to wait at least several more decades to get a better picture but I am struck at how much evidence has changed what we "know" about erectus since I have been on this forum. Some still don't seem to realize that is a pretty good indicator that what they thought they knew was wrong. I guess I am feeling skeptical that we changed that fast and that could be our ancestor and it is bugging me.

Not having the location of the fossil is why most of the Asian erectus, especially the Java ones aren't dated very well not that I think you/vilnoori ever suggested you wouldn't remember where the original fossil was at.

[dogu4]

Both the age and dating technique are interesting. The location likewise is very interesting since it's in a northern region of China, near Beijing. The wikipedia page on the site is pretty good with several good pics of the digs and their surroundings.
http://en.wikipedia.org/wiki/Zhoukoudian
This area, steep hills in limestone karst with old caves some of which have collapsed roofs not porcupine activity, which have preserved for researchers a lot of these erectus fossils suggesting these guys were in the area for quite some time presumably through a range of temperate (and maybe not so temperate at times) continental climates, adjacent to the vast coastal landscape, even more impressive during times of lower sea level, that was a corridor for so many other radiations of big animals. How could they not have made it to North America. That for me is the most intriquing part of this rather incomplete puzzle.

[vilnoori]

Overall impression on incomplete partial skulls is probably not be the best way to gauge relationships, but the Peking man seems to have much more prognathism and looks much more apelike.

Yes, I have my doubts too. They seem so robust, apelike, and really there is little difference between these H. erectus skulls and some of the smaller habilines morphologically. The only significant difference is size. Their bigger cranial capacity is entirely due to an increase in size. Plus there is such a wide variation in habilines, it would be quite possible for georgicus, floresiensis, erectus types and modern types all to have come directly out of different habiline lines that got isolated.

It used to be pretty clear cut, the erectus was "more advanced" than habilines because it was bigger and was found in Asia, far from the supposed point of origin in Africa. But now georgicus and floresiensis are on the scene, you realize that you are actually looking at smaller and bigger versions of the same kind of creature, found BOTH in Asia and in Africa. Only the African dates are earlier. Plus the African Turkana/Nariokotome boy seems to be the ancestor to the erectus, and it is much older and also African. I think it is a dead ringer for sasquatch!

I don't know. Some of the habiline skulls are so modern looking I wonder if modern humans didn't spring directly from them (especially factoring in small size in the more ancient human family like the !Kung San tribesmen), and erectus ended up as Neanderthals. Perhaps erectus are still around, a vestige population of sasquatches. I wouldn't at all be surprised seeing how long they existed in the fossil record. And their technology seemed very conservative for a very long time too. It doesn't seem like there was a lot of innovative thinking going on, not until modern humans originated in Africa and spread so quickly into the rest of the world.

Point taken wolftrax, though I didn't mention moving the bones. Just not cleaning them. I think a lot of people think that biological specimens have to be cleaned, and that is not true.

[vilnoori]

Just some contemplations. If you had access to an earth-like planet with early australopithecines, and you wanted to "tweak" their evolution (and had a time machine and access to anywhere and anytime there), what could you do to? Perhaps you could teach the most human-like, intelligent ones (say, like Homo habilines) to use fire and to cook their food. Or teach them how to shape stone tools and use them more efficiently. You could teach them some very basic hunting techniques. Then, come back in a million years or so, and presto, there you'd have bigger, taller hominins that had much less robust teeth and facial bone structures and are proficient hunters, with the rise in problem-solving that skill set requires. They would have had time to develop behavioural changes. Perhaps then teach them to make rafts or boats, and to pole them, or how to make and use sails. How to preserve food. That kind of thing. It could be done, couldn't it, if you had the technology to reach them at the right time. All it would take is a week or two with a few small tribal units.

Later, you could come in again and teach them to weave, to use agriculture, to domesticate animals. To build. The wheel. etc. But there would have to be certain "quantum leaps" in physiology to make it happen. The transition to uprightness. The ability to speak, that is, Broca's area in the brain, and the structure of the larynx and so forth would have to be there. The brain itself would have to be able to take on the tasks. I think you would be very tempted to use some slight genetic engineering to introduce the very small genetic differences (ie, the speech genes) that would enable a hominin to handle the new information. Hmmm.

Then if you look at the ancient Sumerian (the oldest human civilization) accounts of some of their gods, there are some intriguing correlations to just such a scenario:

At Babylon there was (in these times) a great resort of people of various nations, who inhabited Chaldæa, and lived in a lawless manner like the beasts of the field. In the first year there appeared, from that part of the Erythræan sea which borders upon Babylonia, an animal destitute1 of reason, by name Oannes, whose whole body (according to the account of Apollodorus) was that of a fish; that under the fish's head he had another head, with feet also below, similar to those of a man, subjoined to the fish's tail. His voice too, and language, was articulate and human; and a representation of him is preserved even to this day. [sounds like a diver, doesn't it--vil]

This Being was accustomed to pass the day among men; but took no food at that season; and he gave them an insight into letters and sciences, and arts of every kind. He taught them to construct cities, to found temples, to compile laws, and explained to them the principles of geometrical knowledge. He made them distinguish the seeds of the earth, and shewed them how to collect the fruits; in short, he instructed them in every thing which could tend to soften manners and humanize their lives. From that time, nothing material has been added by way of improvement to his instructions. And when the sun had set, this Being Oannes, retired again into the sea, and passed the night in the deep; for he was amphibious. After this there appeared other animals like Oannes, of which Berossus proposes to give an account when he comes to the history of the kings. Moreover Oannes wrote concerning the generation of mankind; and of their civil polity...FRAGMENTS OF CHALDÆAN HISTORY, BEROSSUS: FROM ALEXANDER POLYHISTOR.

Here's another intriguing bit that really reminds me of what such genetic engineering would look like to someone describing it thousands of years ago:

In the myth of "Enki and Ninmah" recounted above, Enki had man sired by the "engendering clay of the Apsu"--i.e., of the waters underground--and borne by Nammu. The Akkadian tradition, as represented by the "Myth of Atrahasis," had Enki advise that a god--presumably a rebel--be killed and that the birth goddess Nintur mix his flesh and blood with clay. This was done, after which 14 womb goddesses gestated the mixture and gave birth to 7 human pairs. A similar--probably derived--form of this motif is found in Enuma elish, in which Enki (Ea) alone fashioned man out of the blood of the slain rebel leader Kingu. The creation of man from the blood shed by two slain gods is yet another version of the motif that appears in a bilingual myth from Ashur....Man's nature, then, is part clay (earthly) and part god (divine) http://history-world.org/cosmogony_and_cosmology.htm .

Maybe something like sasquatches would be what would result from no tinkering at all.

This post has been edited by vilnoori: Mar 21 2009, 01:01 PM

[bipedalist]

Then again, the UFO and alien possibilities could follow-along these same lines of beneficence

[vilnoori]

Well I think the essential element is a time machine. If you have a time machine, there is no reason to bring aliens into it at all.

[Robert]

Then there is the theory that there are no aliens, never have been. What we perceive as aliens are actually humans from far in the future who are visiting their ancient past -- still tinkering with us.

[ganglian]

Actually this again stresses the importance of leaving fossils where they are found in situ. The tests weren't done on dirt from the fossil but were done at the exact locations and strata layer that the fossils were found in. This was only possible because the location and strata layer was properly documented in the first place.

If you find fossils and move them you are destroying any possibility of reliably dating the fossil.

your avatar is rather distracting

[wolftrax]

That's good, you seem to like distractions.

Anyways...

Very cool fossil. That is very shortly after an extreme warm period where even the Greenland ice sheet melted. Some think that a new migration out of Africa likely happened about that time. Signs of fire were first observed in Europe about that time. Looking at that guy just superficially, it looks very ape like. It has pretty extreme prognathism or protruding jaws and a slanting forehead. I have heard people say this is supposed to be equivalent to our ancestor about that long ago but I find it hard to believe.

peking man fossil.

That is a copy of the 1930s Weidenreich and Swan reconstruction. At the time, not much was known about erectus or comparative specimens. There isn't extreme prognathism there, you'd see extreme prognathism in a chimp skull, but a current reconstruction using copies of the original fossils (the originals were lost in 1941) was made by Sawyer & Tattersal:



Notice it has less prognathism and the zygomatics are smaller. Dated previously at 300,000 - 500,000 years old, and according to this study could be 700,000 years old.

later heidelbergensis about 200,000 years later

Atapuerca 5, 350,000 to 500,000 YA, in your image, is Homo heidelbergensis and found in Spain and is considered a separate species than the erectus found in Asia, and this one particularly shows incipient Neandertal traits such as a projecting mid-face, double-arched browridge, inflated cheekbones, and a gap behind the third molar. It's a transitional species.

Then you have this one of the same age found in Sangiran Java that also seems to look quite different.

There is reason to believe this skull, Sangiran 17, is 1.66 million years old and the Java erectus may have been isolated for the last 2 million years.

Overall impression on incomplete partial skulls is probably not be the best way to gauge relationships, but the Peking man seems to have much more prognathism and looks much more apelike. The Chinese paleontologists commonly think it is an ancestor. That illustrates why bones are really bad for determining relationships and why I don't take what some paleontologists thinks about it as very conclusive. The zygomatic process or cheeks looks quite different if they are supposed to be the same species. The sangiran and peking look like they might be pretty close but even there the sangiran seems to have big eyes.


These are among the few and best erectus evidence. A tooth study showed there were likely two groups and a replacement just before that time. Floresiensis indicates there were at least two groups because they have features found in Australopithecus. Older than a million years old and the Asian erectus had larger teeth and smaller brains. It make me very skeptical of anyone who thinks he can place all or any particular erectus in a family tree. These are supposed the be the same erectus species even according to the tooth study. We will probably have to wait at least several more decades to get a better picture but I am struck at how much evidence has changed what we "know" about erectus since I have been on this forum. Some still don't seem to realize that is a pretty good indicator that what they thought they knew was wrong. I guess I am feeling skeptical that we changed that fast and that could be our ancestor and it is bugging me.

Considering that species often migrate, and Erectus certainly did and we think they did several different times, and species also do tend to have changes as they separate, this isn't that difficult to accept. You do have a transitional species here in Homo heidelbergensis, and that confuses your mix.

Yes, I have my doubts too. They seem so robust, apelike, and really there is little difference between these H. erectus skulls and some of the smaller habilines morphologically. The only significant difference is size. Their bigger cranial capacity is entirely due to an increase in size. Plus there is such a wide variation in habilines, it would be quite possible for georgicus, floresiensis, erectus types and modern types all to have come directly out of different habiline lines that got isolated.

There was a significant difference in brain size to body ratio between habilis and erectus, erectus and ergaster's brains literally balloned. There are also very distinguishing morphological characteristics when comparing habilis and erectus. Take a look at this diagram, erectus's brains grew dramatically compared to their body size:



http://www.brainstages.net/evolution.html

[BobZenor]

That is a remarkable difference on the Peking man reconstruction. It sort of makes you wonder how much preconceived ideas come into this. The fact that they are often shattered reconstructions is one of the reason i have always been skeptical about any assumed status of erectus. Even the Sangiran 17 guy was pretty beat up.

Atapuerca 5, 350,000 to 500,000 YA, in your image, is Homo heidelbergensis and found in Spain and is considered a separate species than the erectus found in Asia, and this one particularly shows incipient Neandertal traits such as a projecting mid-face, double-arched browridge, inflated cheekbones, and a gap behind the third molar. It's a transitional species

I know he is heidlebergensis. I labeled him and the probable time. Some do think they are the same species and both erectus. My only point was that they don't look the same. The extreme prognathism in the early representation of Peking man relative to the other and different bone structure made them look like different species. That was also different enough that I didn't believe the 200,000 years would explain it. The newer reconstruction has them looking like they are much closer related and both could have descended from ancestors that came out of Africa 800,000 years ago. That is more consistent with the Japanese tooth study, which has the potential to be more objective, that showed a replacement 800,000 years ago. If that Peking man weren't very closely related to our ancestor, it would mean that not only some unrepresented primitive version of erectus existed(floresiensis lineage) but also different more human like versions existed as well. Just to be clear, I was having a hard time accepting that version of Peking man as our ancestor 700,000 years ago. If there was a replacement 800,000 years ago, that Peking guy would have to be very close to our ancestor at the time and probably the same species as our ancestor. It just didn't add up. It seemed to imply at least 3 major versions of erectus and that is getting kind of crowded considering races and all. I now think, because of the newer reconstruction, there probably was just two species of erectus in Asia 800,000 years ago. That sort of fits my worldview better but I try not to have preconceived notions.

This post has been edited by BobZenor: Mar 28 2009, 02:34 PM

[wolftrax]

Some people like to throw Ergaster, Georgicus, and Heidelbergensis into the erectus bin but it gets too confusing when discussing them to figure out the lineages and migrations. Basically, ergaster was ancestral to erectus and then later heidelbergensis. Peking man isn't ancestral to heidelbergensis. So you are not having to account for the 200,000 years.

The Heidelbergensis you posted has some Neandertal features, features that distinguish Neandertals as a species. That is a transition and should be treated as it's own species in order to clarify and avoid the confusion of your initial post.

Again, the prognathism in the original reconstruction wouldn't be considered extreme, if you consider that to be the case you should see a chimp skull. there are differences in these skulls, but nowhere near the differences you see when comparing australopithecines, paranthropus, or even habilines.

[vilnoori]

I guess I'm one of those "lumpers." When you consider the huge diversity in skulls of Homo sapiens sapiens it makes me wonder how so many different species names can be handed out in Physical Anthropology. I mean, consider the following skulls from Bone Clones:

Aboriginal Australian: http://boneclones.com/images/bc-031p-lg.jpg

Asian male: http://boneclones.com/images/bc-016-lg.jpg

European male: http://www.boneclones.com/images/bc-107-lg.jpg

African male: http://www.boneclones.com/images/bc-110-lg

And that's not even looking at different sizes, like pygmy's or giants, and different ages and so forth. I have a great time looking at people in public places, looking for so called "archaic" features in their skulls like heavy brow ridges, slanting brows, no chin, etc. Wierd past-time , I know.

[wickie]

After reading through some of this thread, I've come to the conclusion that It's always good to find a good erectus
( sorry!)

[BobZenor]

Some people like to throw Ergaster, Georgicus, and Heidelbergensis into the erectus bin but it gets too confusing when discussing them to figure out the lineages and migrations. Basically, ergaster was ancestral to erectus and then later heidelbergensis. Some people like to throw Ergaster, Georgicus, and Heidelbergensis into the erectus bin but it gets too confusing when discussing them to figure out the lineages and migrations. Basically, ergaster was ancestral to erectus and then later heidelbergensis. Peking man isn't ancestral to heidelbergensis. So you are not having to account for the 200,000 years.

Michael Morwood in his book described a replacement. He said the evidence of the Japaneses tooth study indicated either very rapid evolution or a replacement about 800,000 years ago by a closer relative to humans. That goes right along with other data though the fossil evidence is vague on the matter. Basically the first signs of fire were observed in Europe about that time. It was after a huge warming period that melted the Greenland icecap. That suggests to me that our ancestor in Africa 800,000 years ago spread out of Africa and dominated the whole world. They obviously didn't kill all the more "primitive" erectus if floresiensis is more primitive. We had in Asia larger erectus with smaller brains and larger teeth prior to the replacement. That is a likely closer relative of floresiensis. Some like Morwood seem to think they had characteristics similar to georgicus which was small and supposedly similar to habilis so they would have to grow rapidly. That seem like a very likely development for some hominids after they leave the protection of the trees. They are free to grow larger since they don't depend on trees anymore. We also had about that time very large erectus in Africa like Turkana boy. Homo antecessor managed to live in Europe prior to heidelbergensis but it is an open question what it was but it must not have been very technological if they didn't have fire.

There could have been two species at this point prior to the replacement in Asia and the australopithicine characteristics of floresiensis suggest this possibility as do habilis and erectus cohabiting. Very likely some population of early hominids survived in Asia but the dates of the older ones seem debated. It makes sense that either the descendants of georgicus or Turkana boy made it to Java and were responsible for the larger small brained erectus before the replacement. Morwood also thinks it is possible that the lineage of floresiensis has no fossil evidence apparently back to early Homo.

Peking man is the ancestor of heidelbergensis if the replacement theory is correct and it was the same creature that left Africa 800,000 years ago. I would assume some inbreeding with all of that wave of hominids for perhaps a couple hundred thousand years but they apparently eventually became separated as our separation from the ancestors of Neanderthal about 600,0000 years ago suggests. The similarity of heidelbergensis and some erectus and also the very strong likelihood of it being ancestor of Neanderthals ties together very neatly. The Asian erectus didn't with it looking so different. You would have had to add another species or just assume it to be more primitive than the species that was ancestor of modern humans since it didn't really have time to change much. I find it hard to believe that a more primitive erectus could stop a more technological one from invading so that is basically why I think the entire replacement from an African species is more likely.

The Heidelbergensis you posted has some Neandertal features, features that distinguish Neandertals as a species. That is a transition and should be treated as it's own species in order to clarify and avoid the confusion of your initial post.

Those features are what tie humans to some of the erectus as far as i was concerned. That also makes heidelbergensis a very likely modern human ancestor about 600,000 years ago since that is when we spit from Neanderthal according to DNA evidence. They also call the apparent ancestor of modern humans African heidelbergensis which suggests they interbreed but that seems somewhat dubious if Neanderthal became a separate species at the start of the age of heidelbergensis. The fossil evidence from 800,000 years is rather vague so it is an open question if Homo antecessor in Europe was an ancestor of heidelbergensis but since heidelbergensis ties in neatly to modern humans, that seems unlikely to me.

Again, the prognathism in the original reconstruction wouldn't be considered extreme, if you consider that to be the case you should see a chimp skull. there are differences in these skulls, but nowhere near the differences you see when comparing australopithecines, paranthropus, or even habilines.

It certainly isn't extreme compared to Australopithecines but it is up there with some of the habilis. It was probably a bit careless to use the word pretty extreme but it was only my opinion about an apparent ancestor of modern humans 700,000 years ago. I was inclined to accept the replacement based on teeth studies because teeth don't get interpreted or I should probably say reconstructed. It still would have taken more than one seemingly out of place feature to question it since people who study it close than I seem to think they are closer to modern humans. My model of hominids will probably be updated in a few years when we find a new fossil and there were no doubt discoveries that I am not aware of.

This post has been edited by BobZenor: Mar 29 2009, 12:06 AM

[norcal logger]

I love ya Bob but I'm gonna have to call you on this one:

... since they don't depend on trees anymore...

Everyone depends on trees. "Trees do a body good." "Trees, the other white meat." "Trees, it's what's for dinner tonight."

It's late, I'm tired. Due entirely to my ignorance, your post went whizzing at light speed, right over the top of my head... but I did catch the tree part, and I couldn't resist.

Have fun, Norcal

[wolftrax]

Bob,
This is why splitting names instead of lumping them all together at times can become much more clear.

Morewood's "Replacement" that he was referring to was one of two options. One, basically an ergaster that migrated out of Africa and then into Asia, becoming what we know as Peking Man, becoming the more modern erectus and thus the differences between Peking and Java erectus. Another option is that the Erectus in Asia evolved to what we see in Peking.

What we keep seeing, different waves migrating out of Africa at different times. The ancestor of Peking Man may have migrated out of Africa, and became what we are finding there, but populations of Ergaster still remained in Africa. Ergaster in Africa continue to evolve, some think becoming what is called Antecessor, and then some migrated out to Europe, while others stayed in Africa.

Now the thing about Antecessor is it was basically an Ergaster, but having some slightly different features according to some.

The European Antecessor, like what is found in Spain, evolved into Heidelbergensis, and that is what you are showing in your post. This European Heidelbergensis then evolved into Neanderthal, those developing traits on the skull from Spain are specific to Neanderthal.

However, the Antecessor in Africa also evolved into Heidelbergensis but the African variety, like Rhodesian man. These African Heidelbergensis evolved into modern humans.

But Peking Man wasn't an ancestor of Heidelbergensis. The ancestor of Peking Man, the one that was still in Africa could be, but Peking Man was in Asia.

[BobZenor]

I think Antecessor was probably the same species as Turkana boy or ergaster and some of them likely made it to Europe at least a few hundred thousand years after he died. I don't know how good the dates are but they dated antecessor up to about 1.2 million years and they probably didn't find the first antecessor. It sort of make it hard to say how long the population was separated from the African population before the 800,000 years I was talking about. Then you have the problem of trying to figure out if it is a new species. All we "know" is that our ancestor 800,000 years ago also produced Neanderthal and it was probably very close to heidelbergensis since it must logically have been their immediate ancestor. We are tied to Neanderthal at 600,000 years ago by genetic evidence. That is a very early heidelbergensis. It is a fair bet that ergaster evolved into heidelbergensis. If later antecessor were the same as ergaster they would have also contributed some genes to our species. That would be a near certainty if they were the ancestor of heidelbergensis. If they had separated from ergaster, then they would be a very similar side branch that got absorbed or replaced since we are tied because of Neanderthal at 600,000 years.

Either way, the larger population size and density makes me think they probably developed technology faster in Africa where there were more minds and more competition. That is why I tend to favor the waves out of Africa. Antecessor got there maybe 1.2 million years ago or even earlier. If they maintained genetic contact with the African species then I have to wonder why they split 600,000 years ago. I would also wonder why it took about 500.000 years for the next wave that was modern humans. I think they had the ability to keep them out until advancements in technology, culture or biological differences like language skills overwhelmed them. Hominids were probably always leaving Africa at least in small numbers. It only makes sense that they would try to expand their range. The fact that antecessor bones showed signs of possible cannibalism is probably why it was difficult to migrate. Some evidence for cannibalism is also found at Neanderthal sites.

About the replacement 800,000 years ago. Whoever the ancestors of heidelbergensis was seems like the logical candidate. I tend to think it was a population from Africa which is in that in between time just before heidelbergensis and that makes them rather hard to define. They were probably ergaster just before they evolved into heidelbergensis. I just didn't want to get an argument from someone that calls them erectus since I was splitting them. If the immediate ancestor of heidelbergensis weren't the ancestors of pekingensis, then another species would have had to replace the older ones in Asia assuming that theory was correct. Like Morwood said, rapid evolution was a possibility. That would make the Asian erectus very ancient and it would make them resisting technology harder to explain. We probably lack enough evidence to say for sure what happened and I am probably trying to break down he the species closer than is possible right now. It is very difficult trying to nail down how close any of the Asian erectus are to modern humans.

This post has been edited by BobZenor: Mar 30 2009, 12:15 AM

[vilnoori]

There was a significant difference in brain size to body ratio between habilis and erectus, erectus and ergaster's brains literally balloned. There are also very distinguishing morphological characteristics when comparing habilis and erectus. Take a look at this diagram, erectus's brains grew dramatically compared to their body size:

That graph is very simplistic and does not include all the data. Consider that Homo habilis did not exceed one or 1.5 meters and had an average cranial capacity of around 600 cc (max 660 cc). By comparison, Homo ergaster was a towering 6 feet tall (projected adult height of Turkana Boy) and had a teeny cranial capacity, in comparison, of 700-850 cc. The later erectus types were, again, all pretty tall and had cranial capacities around 1000 cc, which actually falls into the modern human range. So I think mixing ergaster with the other erectus types is a mistake, and I suppose what I should have said was that habilis as a founder species for all is quite reasonable because its cranial capacity is high in relation to its height. To me size makes very little difference because it can change so rapidly in response to environmental changes.

Then again ergaster had some features that make it a candidate too, as Bob proposes. It was old enough as a species, at around 2 million years. It had less sexual dimorphism. It had increased in size, its cranial capacity was beginning to increase, and it had a smaller face and dentition. Most importantly, it was African.

[BobZenor]

I have seen sources that projected his adult brain size at a little over 900. He is a pretty early version and he might be on the lower end of the bell curve.

One reason I don't like labels is that they are used so differently. Ergaster is sometimes used as the name of the African "erectus" and sometimes it is only used as the most ancient African erectus before they evolved into erectus. I think they found an erectus recently in Africa that had Asian and African characteristics so many consider them the same species but I never liked that reasoning. I would prefer a generic name like African erectus but that name implies that I think they are the same species and I don't except when erectus first left Africa and shortly after the possible second wave.

[norcal logger]

You guys and gals are so very well informed. Well, I guess so. I have no knowledge of the subject. Keep up the dialogue, it's like getting a free college course! Thanks

[wickie]

You guys and gals are so very well informed. Well, I guess so. I have no knowledge of the subject. Keep up the dialogue, it's like getting a free college course! Thanks

So true NC, I'm learning more about erectus everytime I read this thread

[vilnoori]

I'd like to know more about the weather changes and sea levels just before and during the Early Pleistocene, 1.8 million years ago to about 780,000 years ago--the time between Homo ergaster in East Africa, and Homo erectus in East Asia and Northern China. Dmanisi Homo erectus (ergaster) remains also were dated to just under 2 million years ago, placing them in the same era. These were the eras of the beginning of the ice age cycles of glaciation and the breaks between them. During these ice ages the sea levels were very low, allowing large areas of land to appear between some major continents (while deserts grew dryer and larger). In between ice ages there were large bodies of water, but greater availability of land farther north. Also it was wetter and warmer, with less desert and more forests.

http://jan.ucc.nau.edu/~rcb7/Pleistmoll.jpg

Gosh I have so much to learn still.

This post has been edited by vilnoori: Mar 30 2009, 11:53 PM

[wolftrax]

That graph is very simplistic and does not include all the data. Consider that Homo habilis did not exceed one or 1.5 meters and had an average cranial capacity of around 600 cc (max 660 cc). By comparison, Homo ergaster was a towering 6 feet tall (projected adult height of Turkana Boy) and had a teeny cranial capacity, in comparison, of 700-850 cc. The later erectus types were, again, all pretty tall and had cranial capacities around 1000 cc, which actually falls into the modern human range. So I think mixing ergaster with the other erectus types is a mistake, and I suppose what I should have said was that habilis as a founder species for all is quite reasonable because its cranial capacity is high in relation to its height. To me size makes very little difference because it can change so rapidly in response to environmental changes.

Then again ergaster had some features that make it a candidate too, as Bob proposes. It was old enough as a species, at around 2 million years. It had less sexual dimorphism. It had increased in size, its cranial capacity was beginning to increase, and it had a smaller face and dentition. Most importantly, it was African.

Using the total body measurements ignores the morphological changes in the body. The diagram given compares cranial capacity to body weight. Turkana boy had a brain size of 880cc, with an estimated body weight of 47kg. That would place it at 18.7 for the brain/body ratio. Estimates for the projected adult (as he wasn't fully mature) body/brain ratio as an adult have ranged from 13.3, which would be just above the later habilis, to 15.6.

Those early ergaster did have an average brain size of 900cc, but they got bigger. OH9, for instance, at 1.2 myo, was 1067cc. Further evidence of Ergaster in later years of Africa are scant, but consdidering that Asian erectus evolved from Africa you have brain sizes going up to 1200cc.

Ergaster and erectus's brains were more complex than habilis. Their bodies were more like modern humans, longer and slender, implying adaptations to a drier more arid environment. From what we know of habilis, they still had the more apelike body, long arms and short legs. Ergaster and erectus developed the Acheulean tool technology from the Oldowan tools habilis used.

Habilis did have large brains compared to their ancestors, and their tool technology was a great accomplishment. But they showed a growth over time, as did ergaster and erectus.

The diagram shown may have been simplistic, in that it didn't show all the hominids possible, but it is a tool to view that overall growth, and that there were huge steps taken in evolution. To say that the only difference between habilis and erectus, or even ergaster, was size, ignores all of the morpholigical changes as well as technology that divides these species.

[dogu4]

I think that more accurately characterising the climate in general and weather in specific of the time period in which the creature in question evolved is critical to understanding the nature of it as(if) it exists in the now. Not doing so explains why our understanding is not able to figure out a way to collect evidence.
One thing I've noticed in maps such as the one referrenced is that the area shown as white, representing glaciated areas, is much too simple and presumes, as we see all the time in science programming that deal with the ice ages. We are frequently regaled with magnificent images of vast unbroken sheet of ice covered lands from Greenland and Antarctica or the Juneau Ice Fields. It seems sensible to use that imagery because we don't have any mid-latitude continental landscapes covered in glaciers with which to compare them, so instead we see towering walls of calving glaciers juxtaposed with skyscrapers of New York. I understand the value of the comparison but I sincerely doubt that it looked much like that, just as the forelands of Alaska's Malaspina glacier or the nearby Brady glacier, which are south enough and close enough to the maritme climates of the North Pacific to be almost temperate, don't look anything like the tidewater glaciers or even the alpine glaciers of Antarctica's coastal areas and dry-valleys. There are some similarities but they are superficial.
Glaciers carry a lot debris (in some geologic perspecitves they are considered the planet's primary terrestrial erosional force) and as a continental glacier spreads into mid-latitude's continental conditions with lots of intense sun, the debris (glacial till and wind borne sediments) concentrates on the surface, causing some melting but also acting as an insulator. The result is a fairly permanent, if slowly moving, landscape with dirt, water and sun and supporting all sorts of communities of plants and animals; drunken forests, kitzlitz murelettes, wolverines and a host of others who can thrive on it. Beyond the edge of the glacier, where the meltwater and terminal moraine become dominant, in mid-latitude climate, while relatively mild with potential for lots of sun, was dominated by a couple of natural phenomenon not currently seen with any regularity these days: huge, really huge wind storms, enormous braided streams and rivers heavy with silt and punctuated by eratic flash flooding on a scale not presently common and not characterised all that well. It boggles the mind to imagine what the terminal moraine zone and the ecotone it would have comprised, would have been like.

As an aside...tonight's NOVA is coving the topic of the pleistocene extinction and examines the relatively new, but increasingly usefull, explanation regarding evidence and conjecture of the 12.9 KYA impact event.

[vilnoori]

Here's an interesting write up that addresses both the weather changes and the comparative tool kits of these early African groups of Homo. It also gives a bit of a time graph to show when they appeared and disappeared. Unfortunately they don't show what areas of the world they were in by comparison.

http://www.uiowa.edu/~bioanth/homo.html

Interesting that the author rejects Homo habilis as a possible founding species for all later forms of Homo, in favor of possibly rudolfensis.

This post has been edited by vilnoori: Mar 31 2009, 02:35 PM

[dogu4]

Excellent information there. Thanks for that.
It'd be nice to overlay this info on a google earth map that displays the kind physical geography and ecosystems that were present while these early pleistocene movements were ongoing. It's sometime hard to imaging a migration if it's all desert and arid coastline, as it is typically portrayed, but if it was dominated by mangrove, for instance, as I have heard it speculated, the migratory path becomes more consistent with what we might suspect a population like our ancestors would need it it were to sucessfully move to a new frontier.
I've heard it speculated that google earth is actually accumulating data that might just allow for something like that.

[vilnoori]

That would be cool.

[vilnoori]

On a related tangent, this article is about stone blades being made 430 000 years ago in Africa! The postulated makers are either Homo heidelbergensis or rodesiensis.

http://sciencenow.sciencemag.org/cgi/content/full/2009/402/2

[BobZenor]

...One reason I don't like labels is that they are used so differently. Ergaster is sometimes used as the name of the African "erectus" and sometimes it is only used as the most ancient African erectus before they evolved into erectus. I think they found an erectus recently in Africa that had Asian and African characteristics so many consider them the same species but I never liked that reasoning. I would prefer a generic name like African erectus but that name implies that I think they are the same species and I don't except when erectus first left Africa and shortly after the possible second wave.

I found this article that talks about the bold part above. They would also find great similarity in Asian and African erectus if there was a second replacement wave presumably out of Africa. They thought erectus split 950,000 years ago which still leaves plenty of time for a more ancient species in Asia. It probably takes a few hundred thousand years for the populations to separate so it isn't really in conflict with my opinion. They just left out the obvious possibility of a more primitive Asian erectus. If there was a warm period long enough to melt Greenland, that would likely bring hominids out of Africa but it is splitting hairs since you can't really tell the population dynamics based on a few fossils. I guess I don't disagree with them as much as I thought.
http://www.sciencedaily.com/releases/2002/...20325080853.htm

The gap between ergaster and heidelbergensis still doesn't have name in this hominid evolutionary tree. That is why what I was talking about was hard to describe.

[BobZenor]

This is how I visualize the main distribution of Homo populations over time. The actual territory for each species would probably be much more extensive than implied. Populations probably became isolated in pockets at times. Much of that time was glaciated. It was likely more complicated particularly early homo but I restricted it to whatever habilis lineage preceded ergaster. Neanderthals made it to Asia on occasion for example so it isn't meant to be exact. I assume Rhodesia man to be heidelbergensis. The data seems in question so it is just eyeballing it from the mental picture I have. It is just a quick easy graphical way to visualize what may have happened. The habilis to floresiensis is based on what seemed to be Morwood's opinion from reading his book A New Human. Erectus probably made it to Asia earlier but it is pretty certain that erectus shared Asia because there was at least one other hominid there the whole time. The idea for how to represent this diagram came from this Link. It is a very interesting article on heidelbergensis and it doesn't differ significantly (since I wasn't trying to be exact) from my representation. My biggest doubt is that I think it likely that all the Asian dates should be earlier.

[dogu4]

Interesting article. Does a nice job at describing the historical context as well as shining some light on the rationale in determining and differentiating species in the context of these still only faintly understood populations.
The graphs are very nice too. They help to envision how these ancient populations existed simultaneously in both time and space...to further the illusion I imagine the plotted areas projected onto a transparent cylinder whose axis length represents time and whose circumference represents geopgraphic relationship, and imagine those population plots' edges fading, overlapping and ablating away. One can speculate just how convoluted pattterns of organic growth can become.
I think it was S.J.Gould who when discussing the family tree starts with how it appears to be made of sturdy branches which on closer examination turn out to be more like twigs and shoots in a very brushy shrub...and lately we've been seeing that if two of these twigs are in close enough proximity they might lead to some remarkable transfers and expressions of genetic info.

This post has been edited by dogu4: Apr 19 2009, 02:25 PM