New Human Species?

[weakmagneto]

Do scientists really lack a satisfactory biological definition of Homo sapiens?

The following article made me think about that question.

Cave Fossil Find: New Human Species or "Nothing Extraordinary"?
Chinese fossils hint at "new evolutionary line"—depending who you ask.

James Owen for National Geographic News
Published March 14, 2012

A previously unknown type of human—jut-jawed, heavy-browed, deer-eating cave dwellers—may have been identified via Stone Age bones from southern China, according to a controversial new study.

http://news.nationalgeographic.com/news ... deer-cave/

Whether the Red Deer Cave remains provide us with a DNA sample to prove how they are related to us, remains to be seen (excuse the pun), but it definitely arouses my curiosity.

[BadgerJelly]

Well I will read this later but you have to take into account China's political agenda. They do not really have a reputation for being tolerant to outside ideas.
I have heard/seen of this sort of thing several times ... then its a question of are we biased in what we believe?

Anyway I won't go off on any more of a tangent just thought it was worth mentioning and will read this latter and let you know what I think :)

[Forest_Dump]

Well, it is an interesting press release. With the current hypothesis being that there were early "out of Africa" migrations into eastern Asia (i.e. Homo erectus) and then a more recent migration by anatomically modern H.s. resulting in potential mosaic blending after close to 1 million years of who knows what kind of evolutionary trends (see for example the Flores hominid), populations with strange characteristics should be expected, particularly if these had been in relative isolation for some time. So I would say this was neat but not surprising.

[owleye]

In the AP Biology text book I'm reading, it mentions two hypotheses: 1) "multi-regional", where Homo erectus in Africa diverged into four out-of-Africa lines and came to interbreed about 100,000 years ago (the mixture theory of homo sapiens), and 2) "out-of-africa" where only one branch of what would become homo sapiens in Africa migrated and subsequently diverged into the four branches about 100,000 years ago, replacing other hominids it found there. What this finding says is that, according to the "out of africa" hypothesis, replacement was uneven, and some of these other hominids lasted until very recently. However, it shouldn't be seen as weighing in favor of one hypothesis over the other without further study and evidence.

James

[Forest_Dump]

Well, I am not sure the multi-regional model is still held by many and the "out of Africa" model does not preclude some interbreeding between "recent" H.s. migrants and resident descendants of even the earliest migrations out. In fact, it seems there is good DNA evidence that anatomically modern Homo sapiens did interbreed with the Neanderthals in Europe so why not other descendant populations throughout Asia, etc?

[owleye]

Well, I am not sure the multi-regional model is still held by many and the "out of Africa" model does not preclude some interbreeding between "recent" H.s. migrants and resident descendants of even the earliest migrations out. In fact, it seems there is good DNA evidence that anatomically modern Homo sapiens did interbreed with the Neanderthals in Europe so why not other descendant populations throughout Asia, etc?

Thanks for responding. It's been ages (during the '70s) since I took the time to make anthropology a study. At that time there was still much talk about the so-called "missing link" and anthropology's response to it. In any case, I'm reading the massive A.P. biology text book as a way of catching up, recognizing of course I'll never get to the leading edge. I confess I've gained a great deal of respect for the text even if it isn't up-to-date and might be misleading in places. Note that though the text (6th ed.), by Neils Campbell (UC Riverside) and Jane Reece (Palo Alto) a publishing specialist, doesn't often refer to the individual contributors and large number of reviewers within the text, it does acknowledge their value. The evolutionary biologist Mark Ridley of Oxford is identified as the main contributor to the chapter which presents the ideas I relayed.

With respect to the status of the hypotheses, the intent of my post was merely to draw a sharper contrast in ways of thinking about the evolution of homo sapiens than might not be evident without it. What I found interesting in these two hypotheses is how they are similar to the difficulty of figuring out origins in general. The DNA (and RNA) analysis, coupled with cladistics has pretty much become the method of choice. Prior to there being some consensus reached, it seems as if two possible ways of thinking about the origin of species (or of life, or of some branch in the tree of life) is to adopt either a monophyletic orientation or a consolidation of mixing. In the deepest branches, it seems that consensus is now moving toward the absence of a single common ancestor to the three domains of Bacteria, Archaea and Eucharyotes", favoring a "ancestral community of primitive cells that swapped DNA promiscuously." However, once these domains developed, the consensus tends toward it being monophyletic, such that a single branch node occurs for each new phylum. As the branch comes to be more recent, however, having less of a evolutionary past, it becomes more difficult to determine origins because, perhaps, there is more evidence that clouds it.

James