Before the Flood

This page is a working paper for what will likely become a brief book.  It is called, 'Before the Flood' not because it references the biblical antediluvian history, but rather a real identified global events called Meltwater Pulses that in aggregate raised ocean levels about 120 meters.  There were three major pulses of which the largest was Pulse 1A.  It took place over a 200 to 500 year period  around 14,000 years ago and raised ocean levels over 20 meters.  These pulses caused breakout floods that often inundated over 250,000 km.

sell throughThe current anthropological and archeological paradigm tells us that anatomically modern humans burst forth from Eastern Africa about 100,000 years ago, occupying the Levant.  After a substantial pause expansions along the Indian Ocean coast all the way to Australia took place between 70,000 and 60,000 years ago and then around 40,000 years ago another expansion took place into Europe.  During all this time H. sapiens were hunter-gatherers.  It was not until the beginning of the Holocene that agriculture was invented and permanent, large human settlements arose.  That is the story but there is quite a bit wrong with it.

First, we build a timeline of anatomically modern humans.  We see recent mtDNA studies that H. neandertalis and H. Sapiens had their  LCA (last common ancestor) 550 to 690 Kya and it was probably H. rhodesiensis.  Likely around 400 and 450 kya the population that ultimately became H. sapiens sapiens became reproductively isolated.  During the next 200 ky the population evolved to modern traits and, at that time, fixed on the mitochondrial Eve and Y-chromosomal Adam.
It then appears that around 70,000 years ago there was a massive migration along the southern coast of Asia.  This may be the result of the Toba catastrophe eliminating the archaic humans in the area.  Later the same population migrated into more northern portions of Asia and into Europe.  By 28,000 years ago anatomically modern humans had supplanted nearly all archaic forms.

It is assumed that between their beginnings and this mass populating of Southern Asia humans were hunter-gatherers.  This is based upon the archeological evidence found to date.  There is a glaring flaw in the logic, however.  From 70,000 to 20,000 years ago the ocean levels were about 120 meters lower than today.  The cities and farms of that time, if they did exist, are now under that much water.  There have been claims of submerged cities off the coast of India that have been met by the scientific community with extreme skepticism.  They actually have it exactly backward.  Rather they should be thinking that if anything interesting was going on 70,000 to 20,000 years ago, it should be found under water. 

The strongest arguments, however, are inferential and Archeological.  The first has to do with morphology and evolutionary genetics.  Archaic humans and anatomically modern humans have significant morphological differences.  First, anatomically modern humans are significantly more gracile.  Second, cranial differences are many.  H. sapiens' eye ridges are less pronounced, skull vaults are high, skull thickness is less and mid-face protrusion is less pronounced.   Archaic humans have a significant 'occipital bun' and a sloping forehead.  In total these differences appear to be one of the most rapid evolutionary events in the history of hominids.

The clincher is this.  While we have no clear explanation for this massive evolutionary change 400 - 100 kya, when humans invented agriculture and settled into cities, there was no corresponding physical adaptation at all.  It is as if humans came pre-adapted to agricultural civilization.  This is contrary to what we know about evolution .  It is far more likely that anatomically modern humans were well adapted to civilization because that is what caused their physical differences to begin with.

Next, one should be astonished by the invention of agriculture, itself.  Emmer wheat first appeared in the Middle East about 12,000 years ago.  Rice, in China was cultivated just a little later.  Squash was domesticated around 10,000 years ago in MesoAmerica and potatoes in South America was not far behind.  While many sources claim seven separate inventions of agriculture over a 6,000 year period, these four are unambiguously independent over just a 2,000 year period.

So the question is, over at least a 70,000 year history, what is the probability that four independent events would take place within a 2,000 year period?  The first event is independent which results in a (1/35)^3 or about one in 42,875 chance.  In other words, something almost surely connects them.  That something is almost surely the warming and climatological stablization that took place after the Younger Dryas, a cold period that ended around 12,000 years ago.

While that is reasonable enough, it begs the question, weren't there any warm and stable conditions anywhere within the human range prior to that?  The answer is, well, yes there were.  In fact, the 14,000 year period between 32,000 and 18,000 years ago was particularly stable.  It was cold where agriculture arose later, but it was warm closer to the equator.  Essentially, if we want to find agriculture during the last ice age we should be looking elsewhere and, for the most part, under 150' to 300' of ocean.

Our best guess is that anatomically modern humans evolved between 320,000 and 130,000 years ago, near the equator and at a place that, during the last ice age had ocean levels about 300' lower than today.  It would need to have significant barriers to migration which could be nothing more than non-arable land.  

This is a viable theory.  In fact, logic and the evidence suggests that it should be the default assumption.  Anatomically modern humans grow food, make tools and build cities.  It is unlikely that we just started doing that in the last 10,000 years of our 150,000 year existence.  It is far more likely that we have been doing it from the beginning and modern Archeologists are just not looking in the places where we were doing it.

Having said that, when anatomically modern humans exploded forth, there is quite a lot of evidence that they hunted and they gathered.  They may have engaged in agriculture as well.  It isn't evident until there are clear morphological changes due to domestication.  However, they seem to very easily supplant the existing hominids.  

I have recently speculated that H. sapiens had a prohibitive advantage over indigenous populations because they had domesticated dogs.  So far there is no evidence that archaic humans did so.  While, until recently, it was supposed that dogs were first domesticated about 7,000 y.a., recent DNA evidence indicates that modern dogs were domesticated from the grey wolf as much as 32k y.a. in Europe.  This matches the approximate time when H. sapiens replaced H. Neandertaliensis.  

Earlier domestications may have taken place but the descendents are now extinct.  What is beyond doubt is that a human/dog pack is both far more formidable as hunters and far less easily predated.  

No Bottlenecks in Human History
We are all descended matrilineally from one woman who lived in Africa betweenf 200kya and 100kya.  We are all descended patrilinearily from one man who lived in Africa between 200kya and 100kya.


1 comment:

  1. I think that the worldwide flood myths don't refer to the melwater pulses of the last interglacial period.
    I think it refers to a much more recent event, the Burkle crater impact at 2900 bc.
    You have to remember that the simplest mathematical estimate for the human MRCA is around 4000 years ago, because there is no isolated population that doesn't share the ancestry of European explorators of the 16th century.
    So, even if the Burkle event must probably have affected the coastal regions of the Indian Ocean alone, if our MRCA happened to found himself in this region he would have transmitted this mythical knowledge to populations migrated to all parts of the world.
    In this case, the mythical flood shouldn't be associated with the Agricultural Revolution, but with the birth of civilization as we know it, that is the culture the cultural revolution initiated by invention of writing systems in Egypt, Mesopotamia and the Indus valley.