Why so important to break sapien, neandertal, erectus & heidelberg into species?

Question

Mathilda, could you post that link of ancient genes I sent you some months back. I can only remember a few, one that Bruce Lahn, U of Chicago, found.

Answer 1

"The modern Australian native & negritos would probably be classified as a differing species (due to brow ridges) if we didn't know better."

As would the pygmies. And those three thousand year old dwarf bones fron Palau would never be seen as fully human.

Really, I don't think they were seperate species, just different breeds/races. Near complete race replacement has been seen several times in recorded history, there's no reason why prehistory should be any different. One country in South America showed not one native American Y chromosome in it's population, even though they know they inter-married with the clolonists quite a bit.

As for the ancient popualtions being seperated, that's just nonsense. The Nile has always flowed into the Mediterranean, so archaic humans would always have had a route from the Horn of Africa into Neanderthal territory. Neanderthals were all over the middle East and North Africa.There was no 'genetic isolation'.

The AM humans that left the horn of Africa had lost their brow ridges. Where did the Aborigines suddenly gain their thicker skull and heavy brows from? (an archaic feature common to the Erectus of SE Asia).

A quick scan through the on line pages of various reputable anthroplogists will tell you The 'Out of Africa' theory isn't as popular as the media make out. I've seen a couple of respected geneticists tear it apart, but it's still pushed hard as the current paradigm. I guess it fits better with the 'there is no race' mantra and 'Adam and Eve' myth.

Answer 2

I have had arguments with someone that suggested that Habilis wasn't closely related to Australopithecus because it is of the Homo genus.  I pointed out , just to get them thinking about it, that at sometime an australopithecus mother gave birth to a homo child and asked them, "do you think the mother and child were similar".  The question seemed to sail over their head.  These labels we give often create artificial and false distinctions.  Clearly if Heidelbergensis evolved into Neanderthal and humans, there was a last common ancestor that was extremely close to Neanderthal and us.  Was that creature Heidelbergensis, man, or Neanderthal.  After evolving for a couple hundred thousand years, perhaps the differences became enough to arbitrarily classify one as separate species but it becomes pretty difficult to do when you are looking at specimens that are closer to the transitional forms or the common ancestor.  If there was interbreeding or hybridization, your task becomes even more impossible.

Answer 3

I don't know Ed, we're probably just comparing Great Danes with Chihuahuas, or French Poodles with Doberman Pinchers...

Answer 4

because a species is by definition a group of organisms that can successfully reproduce with one another to have fertile offspring. Organisms of different,but still closely related species can still have children,but that means  they won't be able to reproduce due to the offspring being sterile. The pack mule is a prime example of this.

Answer 5

Homo neandertalensis, Homo Sapiens, Homo erectus and Homo heidelbergensis  are only tentatively listed as separate species. They could very well be listed as Homo sapiens neandertalensis, Homo sapiens sapiens, Homo sapiens erectus and Homo sapiens heidelbergensis respectively which would be equivalent to listing them as subspecies of the Homo sapiens species and some anthropologists do list some of these as mere subspecies. Modern humans were the first hominid to ever be described scientifically as Homo. Neandertals, Erectines and Heidelbergs are all listed as humans by the name Homo because of their great similarity to us.

Designating them as separate species is not necessarily inappropriate. Functionally, they were very different and there is yet no indication that they were able to interbreed. There are some curious fossils that look like they could be hybrids of sapiens and neandertals but there are other possible explanations for these few little known specimens. None of these fossils are complete skeletons for instance and we can not accurately list them as hybrids without confirming data. Furthermore, many sorts of mutations can yield similar looks as well.

DNA data suggests that Neandertals were indeed very different from us genetically and that difference has never been found in any other population of humans. No modern population of humans has such a dramatically different genome as Neandertals. I am currently unaware of any DNA samples from Heidelbergs or Erectus and suspect they too would show similar variations from the modern "norm."

Even if these populations did meet and exchange DNA, none of that has surfaced in modern populations. This suggests that we are not descended from these other peoples. They are truly extinct with no descendents. Discussions of possible interbreeding are moot without any evidence that they occured. And this is true even if such breeding did happen. We have no knowledge of them. Scientists try to discern if such things could have happened but no legitimate scientist will say they didn't. They have no evidence either.

The plethora of names is largely to help us view our relationships to these other groups of humans and there is nothing disparaging about listing these groups as separate species. Scientists simply do not believe that humans are all that different from other life on this planet. They believe that we evolved with numerous side branches right along with the other animals. Whales have many branches on their family tree and so too do elephants. Our fossils display a similar branching pattern. Mapping out these other branches shows how interesting (and yet how ordinary) our family is.

Edit: ed031639 I'd be interested to see this information for myself. Could you provide a few sites for me to look this up?

From what I've been able to find so far most anthropologists have no problem with Mungo Man being plain old Homo sapiens dated between 30,000 years old to 50,000 years old. I was unable to locate anything about genes of different ages per continent of origin beyond those that support the "Out of Africa" theory. A lot of the information I found was dated before year 2000 and more recent advancements could overturn earlier results as with the age of the find.