Oldest humanoid

[wet1]

Scientists working in Ethiopia have discovered possibly the earliest human ancestor remains to date. Teeth and bones which may be 5.8 million years old and push back the date of the humanoid by 1 million years, of which humans belong as a group to. These bones are believed of be of a forest dweller. This is very close to the time in the evolutionary line when it is thought that humans and apes parted and went their separate ways. Scientists believe that the split occurred between 5 and 8 million years ago.

The evidence appears to be of the Human line, one of the earliest human ancestors. The dating appears to be very solid and what the report tells of the climate of the time is critical. This is a windfall of information. These words by Brian Richmond, an anthropologist at the University of Illinois at Urbana-Champaign, who was not connected to the study. The bones were found in the Ethiopian desert but at the time the creature lived the climate was wet, forested, rattled by volcanic activity.

This clashes with the theory that during this time the drying of the forests was critical to the evolution of humans. This theory holds that humans learned to walk upright because the forests were disappearing and leaving plains in their place and no trees to harbor them.

This fossil was found about 50 miles south of where the fossil of Lucy was found. Lucy was discovered 30 years ago and was dated to 3.2 million years old.

11 speceimens were found including a jawbone with teeth, hand and foot bones, partial arm bones and a piece of collarbone. They represent at least 5 individuals.

So, does anyone have any speculatins as to what point we will reach the common ancestor? Will that common ancestor be in this area geographically?

 

[sader]

Ardipithecus ramidus

This part of Africa is the most significant area yet for paleo hominids. Eventually, the root ancestor of human and ape will be found somewhere in the vicinity of the Afar region.

This species of Ardipithecus may not be a human ancestor. It may be a more significant ape ancestor. Why more significant? No paleo apes of the same age of either Ardipithecus or Australopithecus have been found. A paleo ape would be a windfall of information about the evolution of the apes. Questions about how far environment pushes speciation events could be answered.

 

[wet1]

Locating the origin point

sader
First off, let me say Welcome to the forums!

It is evident that you have some background in Anthropology. Please continue along this line as I do not and wish to know more. So you feel this is the foci of the earliest of humanoids and are satisfied that we will find the "true ancestor" in this locale.

 

[sader]

early homonids

So far all of the oldest hominids have been found in this part of Africa. Some of the later Australopithecines have been found in South Africa, but no where else. Not until the arrival of Homo (as in H. habilis and H. erectus which are from 1 to 2 million years old) do we find anything in Asia or Europe. Most likely the fact that Africa is such a large land mass is the reason for such a huge variety of animal life, to include the homonids. Neandertal (about 60K years old) is exclusive to Europe and parts of the middle east, such as Iraq. There have been no Neandertal findings in Africa. This is not to say there are absolutely no Neandertals in Africa, since remains are extremely rare and actually quite hard to find.

This sort of brings up the prevailing ideas about human evolution in anthropology, namely Out Of Africa (or replacement) and Multi Regionalism. The OOA idea is some homonids out competed their contemporaries, while MR believe that homonids appeared globally at roughly the same time and interbred, or assimilated each other. I could go into detail if you'd like.

 

[wet1]

Please do...

After all this is the place for it. While interested in a large amount of subjects, this one draws my attention (and I would bet the attention of others). What say you to the idea that Neandertal and Homoerectus may not have been genetically compatible? Like cats trying to breed with dogs. (you never see and dog/cat)

Humans have been known to try to breed with almost anything that will try. (Not the group itself but those strange individuals) Could this have lead to the "tribal they're different" syndrome which encouraged the competion for food and territory? What if things had been different? Would our genes show some such connection?

I would think that Africa had the prime weather and survival conditions to encourage such growth. Prehaps a little run down on the weather of the time would also help. Speculations?

 

[rde]

Re: early homonids

Originally posted by sader
This sort of brings up the prevailing ideas about human evolution in anthropology, namely Out Of Africa (or replacement) and Multi Regionalism. The OOA idea is some homonids out competed their contemporaries, while MR believe that homonids appeared globally at roughly the same time and interbred, or assimilated each other. I could go into detail if you'd like.

Cool to have someone informed here. I have a question (if you don't mind): is the OOA theory still taken seriously? Everything I've read over the past year or two would indicate that it's only a few diehards who still cling to it, and that multi-regionalism is the prevailing best bet. Certainly I've been convinced by the arguments.

 

[sader]

paleo anthropology

Of the two prevailing ideas, one really isn't that dominant over the other. They really keep falling in and out of favor as new information is uncovered. Unfortunately, the DNA from even Neandertal is very hard to read because of age. You may have heard of the 'Eve' hypothesis. This idea at first backed the MR idea, then a more refined test actually backed the OOA idea. What the results for humans show is a genetic 'bottleneck' where only a few thousand humans survived a catastrophe (most likely a volcanic event that shut down summer for a few decades, according to the geologists) and we more or less started over with less diversity.

Whether or not human and neandertal were genetically compatible is still being debated. Three or four years ago the remains of a child ~25K years old were found while grading a road in Portugal. Portugal is one of the last areas neandertal lived before disapearing from the record. Unfortunatley, the childs skull was destroyed by the machinary, but the rest of the skeleton was fairly intact, including the lower mandible. The bones were thought to be a mix of neandertal and human landmarks, such as a vertical mandibular symphasis (a human chin) and very heavy and robust long bones (the humerous and femur) which are distinctly neandertal. Is this a hybrid? DNA testing was done, and I beleive was inconclusive again due to age. DNA is wonderful for relatively recent things, but very tricky for older remains.

Paleo anthropolgy is not exactly an exact science, since it deals with mostly extrapolated data from other sources. Dating is done by a variety of methods, including other flora and fauna found with the homonid remains. Anthropological digs often involve geologists, entomologists, botanists, etc.

 

[wet1]

Climate of the area is also of interest to me. What do the trapped parts in amber, ice, ect. look like compared to today? How far off have we wandered from the pristeen atmosphere for that time?
Any ideas?

 

[sader]

climate for paleo hominids

I'm not aware of any amber being associated with hominid finds. As far as the climate being different from now, it was really not too different. Most of this data is taken from ice cores, which is the major data source for glaciations. Dendrochronoligy (tree ring data) is another source for climate readings.

Most of the Ethiopian finds are in a rift zone, with mucho vocanic activity. There are 'death zones' in this part of Africa where CO and CO2 get trapped in depressions, killing any living thing that happens to wander in. Plantlife, however, thrives like crazy. It is this vocanic tuff that plays an important part of dating, such as Ar39 /Ar40.

There is no real good definiton of pristeen, since the volcanoes from this epoch emitted so much carbon and sulfide gasses into the atmosphere. The world has had several major ice ages, the last one being ~10-15K years ago. Incidently, the black plague was precipitated by a mini ice age. Crops failed in the agricultural area of Europe, sending all those farmers into the cities like London. The resulting crowds helped spread the fleas which carried the plague.

 

[kmguru]

Thank you sader.

Someone told me that they found, humanoid remains next to dinosaur bones. Is that true or he was BSing?

If humans have been learning and evolving for the last 6 million years and have full intelligence for the last say 15000 years, can an anthropologist extrapolate what type of life form, we will become in say another 100K, 500K or 1M years?

Has there been any indication that in the last 6 million years, we became agarian in only say last 15K years ? and that there have been no 5 or 10 agarian societies sprang up and died out in the last 2 million years?

I would like to know, if it took us that long to learn and evolve or we eveolved pretty rapidly. A million years is a long time for hunter/gatherers - considering the life span was probably 25 years.

Another thing puzzles me is that how come our ancestor life span is shorter than Apes or was it?

 

[wet1]

I would say that a lot had to do with living conditions and enviroment.

 

[Javier]

My point of view about the OOA-MR controversy

I m for the OOA.


Although the DNA analisys would be the ultimate proof,and has yielded a majority of results favouring the OOA,I wont mention it for is not totally uncontradictory(hope gets perfected soon)

In any species evolutive tree the common ancestor is more closely related with any of its descendants than any of the colateral descendants between themselves(you are more related to your grandfather than to your cousin);but if this is true,according to multirregionalism...the italians and the chinese are more akin to homo erectus /ergaster than between each other¡¡¡


If the paralell evolution that they propose to explain the present ressemblance of humankind as a whole is due to the need to develop tools,as they say,it would have affected only the brain,the hands,and the nerves that relate them;but all the other features would have had to continue its divergence,in very different environments,making obvious in the present not races but that they are different species,for even not having changed they would have to be at least like the erectus parts(which they obviously arent )...





But going to the hands and brain issue,if is true that evolutive convergence does happen,it is as well the fact that the ressembling organs(they cannot but follow the rule of the rest of the body)are ,in an intimate genetical structural scale more related to the common ancestors organs than between themselves,and this is a consecuence of evolutive mechanics, advanced DNA analisys only to confirm (think in the wings and fins of bats and whales:they are clearly more close to their ancestors paws than to bird s and shark s;in this example the tremendous evolutive/temporal distance makes it more relevant,but the keypoint is that the evolutive process is exactly the same)



The multirregionalists try to temperate this flaws by the so called "gene flux",(that would had mantained the unity worldwide)but it s quite suspicious by itself:
Because each of this supergenes would have had not only to be succesful within its community of origin,but to defeat every equivalent(in the sense of doing a similar function)gene in ALL the other communities(worldwide,with the differences that this means in terms of environment,bio-systems,climate,etc))exactly(at species level)in the same cases(for if not differences would lead again to species diverging) ¡¡¡


The rate of mutations within a given group would be always bigger than the (very rare)incoming of the supergenes(they are exceptional),making ever more difficult for one to "unify"the species


Of course to live in the same place can lead to some convergence,as the successive species have to deal with alike regional problems,and this is what multirregionalists identify as proof of a regional evolutive continuity,explainable by focalized convergence(only in minor characteristics) much more easily than to say that the whole species evolved separatedly and is alike in general(even to the DNA¡¡) by convergence...


As long as h.neanderthalensis seems to be an independent product of the erectus-antecessor-heilderbergensis line,then multirregionalists have to mantain that the erectus branch diverged to this form and then converged to modern humans(with which by the way neanderthalers coinhabited,but being a different species(not race)racism(specism?) would have been very strong,even if theoretically viable the interbreeding))


So,we have here not one,but a handful of strange conditions ;is not only much more simple for the usual to happen(all the rest of studied species evolved according to the OOA model,the way A.R. Wallace pointed out in his comment on how species tend to diverge from their original branches)but for chauvinist interpretations to occur:


The multirregionalists are willing to prove that EVERY evolutive pathway can lead to one and only form of intelligent being:themselves.

(Also would be very continentally democratic)

Candidate for ancestor of all hominids:Australopithecus afarensis.

Will seize the chance of this very rare thread about evolution to post an idea concerning native americans(the continent):


Seems to be that the first inhabitants got to the continent about 13000 years ago;1000 later,fossils were found in the southernmost tip(Tierra del fuego),but as all indians are remarkably alike,then they didn t change in any noticeable way,for if not they would be different from,say,North to South America;but having only 1000 years to cover all the continent s lenght that would mean that they came as they are from Asia(they didn t have time to evolve in America),in where they became extinct or evolved in turn...

 

[sader]

questions from kmguru

1- They were BSing you. Humans and dinosaurs only lived together on the Flintsones.

2-No, the anthropologists really cannot say what we will be like in the future because we are so good at altering the environmnet. We can live anywhere without harm. Space, underwater, on top of mountains, deserts, etc. The environment plays a huge part in evolution. Most beneficial mutations are from some sort of environmental adaptation. For example, lets look at teeth.
Ardiithicus ramidus is thought to be on the human side of things largely due to its teeth. Chimps and gorillas have these really huge thick enamled teeth because they are pure (in the case of chimps, mostly) vegetarian. Our teeth, and those of ramidus are rather small and thinly enamled. We began to cook our food, which even further reduced our tooth size. The teeth are the most unstable evolutionary part of our body. About the time of the Egyptians, tooth abcess from cavitys began to kill people off rather frequently. This is seen in the remains of mummies, where the bone surrounding the last molars (wisdom teeth) is often pitted from infection. We were just about ready to loose the wisdom teeth because they had become more deadly than useful, when denstistry, a technology driven activity , began to pull the infected teeth before sepsis could kill. Our technology altered an environmental adaptation.

3-Yes, the evidence is clear that we became agrarian in the last 10-15K years. There have been many agrarian societys, from chiefdoms through city-states (like the Mayan, Aztec, etc.) that have either become extinct or assimilated by another society.

4-An anthropologist named White once observed that if a society was stagnant technologically, they became extinct. This is what happened to the neandertal. In homonids, you'll see the terms 'robust' and 'gracile'. Neandertal was robust, Homo sapeins is gracile. The 'gracile' homonids were always more succesful than their robust cousins. The gracile H. erectus was probably the first to use fire, cooking both vegetation and meat. This increased the nutrional allowance from the food, which is beleived to have increased the capacity and size of the brain. If you ever get the chance to look the post-cranial skeleton of an Australopithcine and an anatomically modern human, they are very, very similar. It is the skull which is very visibly different. Using fire aletered our environment, and our genes responded. As far as the short lifespan, there is evidence that pubery happened sooner back then. Also remember that males can breed no matter at what age, females can only breed for so long before menopause occurs. There were no nuclear families, more of an extended family with males and/or females moving to other groups, sort of instinctively adding variety to the gene pool as well as bringing in new ideas and technologies to the new groups.

5- Humans and apes actually have very similar lifespans.

A number of years ago, I was curious about whether or not neandertal was part of the human family tree. A difference in Homo sapiens neandertalensis (human) and Homo neandertalsensis, not human. I began looking at the evidence from the MR and OOA groups, and I was swayed by the OOA group despite the fact that I badly wanted poor misunderstood neandertal to be human. I belive that the truth is actually somewhere in the middle between the OOA and MR groups.

 

[wet1]

Homo heidelbergensis

Common ancestor
In the picture is a replica head of Homo heidelbergensis - one of 32 people found in Atapuerca and dating back 300,000 years.
It is based on a skull found in Sima de los Huesos (Pit of Bones), Europe's oldest known burial site, in Atapuerca. Some scientists think Homo heidelbergensis was the last common ancestor of the Neanderthals and today's humans.

From BBC

I would say that there seems to be something seriously wrong with this date. I found this today and thought of this thread.

 

[Javier]

Some scientists consider h.heilderbergensis as sole ancestor of the neanderthalers,and african advanced erectus form (presently found only in Europe,in Atapuerca)h.antecessor(-800,000 years)as common ancestor sapiens-neanderthalensis.



In times(don t know if still)neanderthalers(unfairly underestimated I agree) were supposed to descend from h.sapiens steiheimensis,and therefore a sub-species in relation to us(h.sapiens neanderthalensis)...



But if they were, as seems, a separate species,they would have been extraordinary,in the sense that having an average cranial volume higher than modern humans(the encefalization quotient(body mass-brain mass) is the most relevant way to determine the intelligence of a species(the quality of the material follows as clue),h.neanderthalensis was the only creature ever lived to more or less equal(they were more robust) h.sapiens sapiens in this field)but evolved independently,their intelligence would have been different,although almost comparable to ours,and,if is true that our own was generally more effective,in some fields they must have been better...



H.erectus modjokertensis and pekinensis co-inhabited in China with the so far found biggest primate ever lived,Gigantopithecus blacki;albeit only his jaws have been found,(they are twice as large as the mountain gorilla) is thought to has standed 2,5 mts(8 feet)and weighed about 660 pds(300 kg)

 

[sader]

H. heidelbergensis

Wet1, nothing wrong the date. Heidelbergensis' range is 400-100K years ago, while neandertals is 150-30K years ago. If this range is pretty much true, than heidelbergensis could very well be an ancestor of both H. sapiens and neandertal. There is always the possibility of an intermediate species between heidelbergensis and the neandertal/sapeins lineage.

The Atapuerca bones have many neandertal features, such as a double arched supra orbital torus, receding symphysis (no chin), a retro molar space, and large posteriorly projecting coronoid process. The teeth, however, point more towards sapiens. I must point out that many of these same features are found in Homo erectus. There are not alot of diagnostic morphological differences between H. erectus and heidelbergensis. Is heidelbergensis a case of anagenisis? Or simply a subspecies of erectus and H. antecsessor? Only more funding for more digs and more funding for researchers to compare the bones will tell.

 

[wet1]

There are a lot of terms you have used to describe the various states of bones and features in the cranial area. While I can go and research, it would probably be more illuminating to explain for all. So some background could be in order.

Please go into a little detail on:

Atapuerca bones
double arched supra orbital torus
receding symphysis
retro molar space
projecting coronoid process

Some of these terms make perfect sense to me, having a bit of medical background. But I think for a lot of the readers it will not.

 

[sader]

sorry......I get carried away.....

The remains from Atapuerca are ~1300 human fossils representing ~30 individuals. Atapuerca is in northern Spain, and a significant site because of the density of material.

The double arched supraorbital torus is what one could call the brow ridge that the neandertal is famous for. This is a thickening of the bone just above the eye socket. Erectus has one, as does H. antecsessor, erectus, habilis, and some of the archaic H. sapiens.

A receding symphasis means there is no point at the end of the chin. Homo sapeins has one, as do some the last neandertals (or is more recent a better description?) but not too many of the other homonids.

The retromolar space is a space between the last molar and the ascending ramus (jaw bone). If you stick your finger in your mouth and touch the last molar on the lower jaw, then slide your finger backward onto the gum, you'll feel the bone begin to immediately begin to slope up. Neandertal, heidelbergensis, erectus, etc. have enough space for a tooth or two before the slope begins. Again, some neandertals that date close to the end of their existance have lost the space.

The posterior coronoid process is the the upper forward part of the lower jaw that attaches muscle to the jaw to the side of the head. These are the chewing mucsles, and in relation to the teeth, identify diet. A large process equals bigger muscles for a tougher, more fiborous (and harder to chew) diet.

 

[wet1]

From the BBC:
Meet the Neanderthal

Unfortunately the images are copywrited and so have not been added to the post.

Reconstructions of Neanderthal skulls add to growing evidence that the creatures were not close relatives of modern humans.
The distinctive features of the Neanderthal skull were established in early infancy - possibly even in the womb - say researchers in Switzerland.
Their conclusion is based on sophisticated computer graphics charting the cranial development of Neanderthals, from babyhood to adult life.
The findings support the idea that Neanderthals did not interbreed with early modern humans and contributed little or nothing to the present human gene pool.
'Sister' species
Christoph Zollikofer and Marcia Ponce de León of the University of Zürich used fossils to construct 3D virtual computer images of the skulls of Neanderthals and early modern humans.
Physical differences in skull development - such as the Neanderthal's receding chin and low, sloping forehead - were fixed by the age of two years, said Dr Zollikofer.

A modern human child (left) and a Neanderthal child (right)
"Most of what makes a Neanderthal and what makes a modern human is already present in the infant," he told BBC News Online.
This suggests that Neanderthals were a separate "sister" species from modern humans.
"We don't see any evidence of gene mixing at all," he said. "But we can't prove this."
Mysterious demise
Neanderthals were an ancient race of people that lived in Europe, the Near East, Central Asia, and probably western Siberia more than 100,000 years ago.
Their mysterious demise about 30,000 years ago has been the subject of much debate and speculation.
Some believe that the Neanderthals were killed off by a new type of human which began to take over their hunting grounds during the middle of the last Ice Age.
Another theory is that the Neanderthals disappeared through interbreeding with humans.
Recent DNA analysis of three Neanderthal skeletons suggests that they were not our ancestors but a sidebranch of human evolution.
The Swiss research, published in the scientific journal Nature, seems to support that view.