Homo naledi has been dated
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Now the dating has been completed - by three difference means - and the results are highly unexpected. These people lived sometime between 236,000 and 335,000 years ago. In other words, they coexisted with other homo species like homo erectus that led to us.
The bush of human evolution just got bushier. Expect to hear more as this discovery is processed!
I did see this news a week or so ago and was a bit shocked.
"The branching image of human evolution (you know, a tree where one discrete species branches off from an earlier species, forming its own more recent species) appears to be dead. Hominid mixing and remixing appears to be fundamental to our lineage. We are an amalgam of genes contributed by many populations. A popular candidate for improvement is the model of braided stream. As I've conveyed elsewhere:
"Lee Berger (Chief investigator of the Red Star Expedition that discovered Homo Naledi) presented an emerging metaphor to illustrate the history of Homo. A braided set of lineages, interbreeding and separating repeatedly, many genetic streams flowing downhill to the lake that is us, but impossible to clearly know how much any particular stream contributed to who we are."
I came across a piece by Professor Clive Finlayson Director, Gibraltar Museum, who works on Neandertal occupation of caves, people whose presence is preserved in caves in Gibraltar. This is from December 2013. He puts the emerging picture in a lovely and thought-provoking perspective (http://www.bbc.com/news/science-environment-25559172) I have cut and pasted for efficiency:
"I have been advocating that the morphological differences observed within fossils typically ascribed to Homo sapiens (the so-called modern humans) and the Neanderthals fall within the variation observable in a single species...
It seems that almost every other discovery in paleoanthropology is reported as a surprise. I wonder when the penny will drop: when we have five pieces of a 5,000-piece jigsaw puzzle, every new bit that we add is likely to change the picture.
Did we really think that having just a minuscule residue of our long and diverse past was enough for us to tell humanity's story?
...The conclusion that I derive takes me back to Dmanisi: We have built a picture of our evolution based on the morphology of fossils and it was wrong.
We just cannot place so much taxonomic weight on a handful of skulls when we know how plastic - or easily changeable - skull shape is in humans. And our paradigms must also change.
...Some time ago we replaced a linear view of our evolution by one represented by a branching tree. It is now time to replace it with that of an interwoven plexus of genetic lineages that branch out and fuse once again with the passage of time.
This means, of course, that we must abandon, once and for all, views of modern human superiority over archaic (ancient) humans. The terms "archaic" and "modern" lose all meaning as do concepts of modern human replacement of all other lineages.
It also releases us from the deep-rooted shackles that have sought to link human evolution with stone tool-making technological stages - the Stone Ages - even when we have known that these have overlapped with each other for half-a-million years in some instances.
The world of our biological and cultural evolution was far too fluid for us to constrain it into a few stages linked by transitions."
We must open our minds to a more flexible view of species. In fossils that represent change over time, we are not necessarily seeing reproductively isolated populations that classically give rise to new species as they diverge from a mother population. We are seeing long term changes in actively mixing populations, exchanging genes all along, and changing over time. This may be the hallmark of human history. In contact with other populations, we mix. We are not distinct from those contributing populations; they are us; we are them."
I dated her for a while when we were younger and then we went our separate ways. Or maybe we didn't...
Of course, we don't actually see the individual streams, just the odd snapshot taken here and there along the length (if we're lucky). The image that always comes into my mind is trying to watch some sort of team game through a hole in the fence when you can't get your eye very close to the hole.