Humanity came from around 2000 persons?

[achilles12604]

http://news.yahoo.com/s/ap/20080424/ap_on_sc/close_call

I found this VERY interesting because up until recently, I had assumed that pure evolution was plausible. That many thousands of humans had evolved and expanded over the course of a the last million or so years allowing our population to be so huge today.

But this article suggests two things I find interesting.

1) We were down to a few thousand people just 70,000 years ago. This of course severely limits the numbers of people which could have evolved over the course of a couple million years.

2) There is reason to believe that the entire human race may have come from a "mitocrongrial Eve".



What does the forum think? Is this trouble for traditional evolution? Will the theory need to be re-worked? And last, is this the beginning of scientific evidence supporting a literal reading of Genesis?

[achilles12604]

Another link to same story

http://www.thedenverchannel.com/health/ ... etail.html

[sfs]

The article in question (the one the news report is about) doesn't actually say anything about a population bottleneck 70,000 years ago. In fact, it doesn't offer any estimates of population size at all. What the paper does offer evidence for is marked population structure in the ancestral African population, i.e. there were at least two populations that had little genetic contact for a long time. This is interesting (and plausible), but it says little about the overall size of the population at the time.

The figure of 2000 persons is attached to some other study, one they attribute to Stanford, but they don't say which study so it's a little hard to figure out how recent it is (or what it actually says -- news reports not being very reliable guides to that sort of thing).

[MeowTseTung]

What does the forum think? Is this trouble for traditional evolution? Will the theory need to be re-worked? And last, is this the beginning of scientific evidence supporting a literal reading of Genesis?

Okay, what exactly is challenging "traditional" evolution? A traumatic event (whether it's drought, volcanism, etc.) decreasing the human gene pool doesn't really trouble the validity of evolution.

This sounds similar to the Toba Catastrophe Theory.
http://en.wikipedia.org/wiki/Toba_catastrophe_theory

[byofrcs]

http://news.yahoo.com/s/ap/20080424/ap_on_sc/close_call

I found this VERY interesting because up until recently, I had assumed that pure evolution was plausible. That many thousands of humans had evolved and expanded over the course of a the last million or so years allowing our population to be so huge today.

But this article suggests two things I find interesting.

1) We were down to a few thousand people just 70,000 years ago. This of course severely limits the numbers of people which could have evolved over the course of a couple million years.

2) There is reason to believe that the entire human race may have come from a "mitocrongrial Eve".



What does the forum think? Is this trouble for traditional evolution? Will the theory need to be re-worked? And last, is this the beginning of scientific evidence supporting a literal reading of Genesis?

No, Genesis can only be read as an allegorical foundation story given that the so-called "mitochondrial Eve" and the "Y-chromosome Adam" lived (metaphorically) over 30,000 years apart from each other (using 30 years per generation).

The male Y-chromosome came with the X around 300 Million years ago from an autosome according to an older study by the Howard Hughes Medical Institute (published in Science in 1999) so the Genesis is fatally flawed anyway by pre-dating Adam (who has XY) from Eve (who has XX). This misogyny is probably deliberate.

Unless God looks like whatever the common ancestor of humans of 300 million years ago, in no way would it look like anything near the modern human and in no way would the timecales coincide even with the most liberal of Genesis readings.

Same problem applies to the Qu'ran too as it looks like a cut+paste job of the Bible.

[Jerada Davidhefter]

Isn't the fact that humans were, indeed, down to a few thousand members proof enough for our evolution from cro-magnon man? In a way, we became less suited for our environment with that development, and were suddenly being torn apart by lions and collapsing due to heat exhaustion. The shift from our previous form to current Homo Sapien took an estimated two thousand years. Truly the blink of an eye. Our brain nearly doubled it's blood flow- leading to the roughly 40-60% at any given time residing there. Our muscles suffered, and the collective tribes decided to flee to Europe, a much gentler climate. So it is only due to evolution and our increased intelligence that we even exist.

[sfs]

Isn't the fact that humans were, indeed, down to a few thousand members

It's not a fact that humans were down to a few thousand members. Genetically we look like we've had an effective population size of at least 10,000 for a long time (which would translate into a census size a good deal larger than 10,000).

proof enough for our evolution from cro-magnon man?

"Cro-Magnon" doesn't have much meaning these days as a scientific term. To the extent it does, it just means early modern humans in Europe. Those of European ancestry are descended from Cro-Magnons, while those with ancestry from other parts of the world by and large do not.

In a way, we became less suited for our environment with that development, and were suddenly being torn apart by lions and collapsing due to heat exhaustion. The shift from our previous form to current Homo Sapien took an estimated two thousand years.

Estimated by whom? And what previous form are you talking about? No one knows how long each change took. Indeed, some are still going on.

Truly the blink of an eye. Our brain nearly doubled it's blood flow- leading to the roughly 40-60% at any given time residing there.

Our brains changed over millions of years, not a few thousand.

Our muscles suffered, and the collective tribes decided to flee to Europe, a much gentler climate. So it is only due to evolution and our increased intelligence that we even exist.

Most tribes did not flee to Europe. Most humans stayed in Africa. Outside Africa, humans expanded into every region that could support life, including some remarkably inhospitable ones. Europe includes a considerable range of climates, many of them not at all gentle.

[Jerada Davidhefter]

One should do some research before attempting to dispute scientific theories.

Our brains changed over millions of years, not a few thousand.

What is considered 'modern' man hasn't even been present for more than 75,000-200,000 years. We experienced a period of hyper-evolution, much as any organism does after a few generations of extreme duress.

Most tribes did not flee to Europe. Most humans stayed in Africa. Outside Africa, humans expanded into every region that could support life, including some remarkably inhospitable ones. Europe includes a considerable range of climates, many of them not at all gentle.

Most humans did not stay in Africa, otherwise we would have ceased to be. It is true, upon our first venture to Europe, a good portion decided to migrate east, populating what we now consider 'The Middle East' This is due to the Neanderthal competition for resources, apart from dangerous climates.

The neanderthal man and woman (related to homo sapien by a common ancestor) were roughly the same size, and held a far superior musculature, yet possessed comparably smaller brains. These attributes led them to be a society of all hunters, and thus encouraged nomadic behavior. The Hunter/Gatherer division of Cro-Magnon man was detrimental at first, but in time, allowed us to develop sites for permanent residence, and the eventual economic domination of our cousins.

Their short-term advantages forced us down to a population of roughly 2000, (look it up anywhere) and eventually to areas which were uninhabited.

[sfs]

One should do some research before attempting to dispute scientific theories.

One should. One should also know what current scientific thinking is before attempting to teach it to others.

What is considered 'modern' man hasn't even been present for more than 75,000-200,000 years. We experienced a period of hyper-evolution, much as any organism does after a few generations of extreme duress.

Our ancestors' brains expanded fairly steadily over a couple of million years. Here's a plot of cranial capacity vs time

Which two thousand years do you want to pick out of that distribution as the critical one? And what is the evidence that the change took two thousand years?

Most humans did not stay in Africa, otherwise we would have ceased to be. It is true, upon our first venture to Europe, a good portion decided to migrate east, populating what we now consider 'The Middle East' This is due to the Neanderthal competition for resources, apart from dangerous climates.

We can get quite a nice handle from genetic diversity on which group was larger, those who left Africa or those who stayed. The data are quite clear that a comparatively small group left Africa. For example, see Jeff Wall's paper in Genome Research (published online in May 2008), "A novel DNA sequence database for analyzing human demographic history", which reports European genetic diversity to be only 69% of African diversity. There are many other papers with similar results.

The neanderthal man and woman (related to homo sapien by a common ancestor) were roughly the same size, and held a far superior musculature, yet possessed comparably smaller brains. These attributes led them to be a society of all hunters, and thus encouraged nomadic behavior. The Hunter/Gatherer division of Cro-Magnon man was detrimental at first, but in time, allowed us to develop sites for permanent residence, and the eventual economic domination of our cousins.

What is the evidence that hunter/gatherer groups were at a disadvantage compared to hunters?

Their short-term advantages forced us down to a population of roughly 2000, (look it up anywhere) and eventually to areas which were uninhabited.

"Look it up anywhere?" Like where, exactly? See, for example, A. Keinan et al, "Measurement of the human allele frequency spectrum demonstrates greater genetic drift in East Asians than in Europeans", Nature Genetics 39:1251-1255 (2007) which looks at genome-wide diversity data and found clear evidence for a genetic bottleneck in Europeans and Asians, but none in West Africans. See also Schaffner SF et al, "Calibrating a coalescent simulation of human genetic variation", Genome Research 15:1576-1583 2005), which shows similar results.

[Goat]

One should do some research before attempting to dispute scientific theories.

Our brains changed over millions of years, not a few thousand.

What is considered 'modern' man hasn't even been present for more than 75,000-200,000 years. We experienced a period of hyper-evolution, much as any organism does after a few generations of extreme duress.

Most tribes did not flee to Europe. Most humans stayed in Africa. Outside Africa, humans expanded into every region that could support life, including some remarkably inhospitable ones. Europe includes a considerable range of climates, many of them not at all gentle.

Most humans did not stay in Africa, otherwise we would have ceased to be. It is true, upon our first venture to Europe, a good portion decided to migrate east, populating what we now consider 'The Middle East' This is due to the Neanderthal competition for resources, apart from dangerous climates.

The neanderthal man and woman (related to homo sapien by a common ancestor) were roughly the same size, and held a far superior musculature, yet possessed comparably smaller brains. These attributes led them to be a society of all hunters, and thus encouraged nomadic behavior. The Hunter/Gatherer division of Cro-Magnon man was detrimental at first, but in time, allowed us to develop sites for permanent residence, and the eventual economic domination of our cousins.

Their short-term advantages forced us down to a population of roughly 2000, (look it up anywhere) and eventually to areas which were uninhabited.

Actually, neanderthal had a larger brain than Cro-Magnon. What it neanderthal did not have is adaptability to a plains environment. The forests in which Neanderthals
were attuned to disappeared in Europe at that time, and gave way to plains. Neanderthals body was more adapt at getting close to prey, but did not have the speed the more gracile Cromagnon did, nor the long distance weapons for hunting cro-magnon did. Therefore, Neanderthal was out competed for food source by the new comers , in a land what whose environment changed on them.

[McCulloch]

What is considered 'modern' man hasn't even been present for more than 75,000-200,000 years. We experienced a period of hyper-evolution, much as any organism does after a few generations of extreme duress.

From Wikipedia:

Anatomically modern humans first appear in the fossil record in Africa about 130,000 years ago, although studies of molecular biology give evidence that the approximate time of divergence from the common ancestor of all modern human populations was 200,000 years ago.[7][8]

Geneticists Lynn Jorde and Henry Harpending of the University of Utah propose that the variation in human DNA is minute compared to that of other species. They also propose that during the Late Pleistocene [130,000 - 10,000 years ago], the human population was reduced to a small number of breeding pairs " no more than 10,000, and possibly as few as 1,000 " resulting in a very small residual gene pool. Various reasons for this hypothetical bottleneck have been postulated, one being the Toba catastrophe theory.

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[7] Human Ancestors Hall: Homo Sapiens - URL retrieved October 13, 2006
[8] Alemseged, Z., Coppens, Y., Geraads, D. (2002). "Hominid cranium from Omo: Description and taxonomy of Omo-323-1976-896". Am J Phys Anthropol 117 (2): 103"12.