08-06-2004, 02:13 PM
Largely based on a special edition of Scientific American "New Look at Human Evolution" (highly recommended as a useful round up of current thoughts on this subject; should be available in your newsagent's till August 25th) I intend to analyse the overview of what exactly is meant by "modern human", as this compendium incorporates both sound research, and some incredibly biased and wrong headed opinions; I hope others will read the whole magasine so we can compare notes?
First post: Wild assumptions!
The perceived wisdom is that Neandertals are extinct, and that "modern" humans emerged from africa less than 200,000 years ago. Apart from the logistical implausibility that the decendants of one mother could have displaced the world's other populations of near humans, in so short a time, the mitochondrial argument, as put forward by two protagonists (one of whom is dead) in "the recent African Gensis of humans" (page 54) clearly applies just as well to the more plausible "the multiregional evolution of humans" (page 46). This is a prime example of how even scientists can latch on to a particular "explanation" without regard to the facts (more on this in a following post).
Is this relevant to the supposed Aspie/Neandertal link? Absolutely, as these articles are riddled with the attitude "I'm a modern human, Neandertals are not; they must therefore be inferior!" (sounds familiar?).
Example: That Neandertals where considered shambling ogres was largely due, in part, to the assumption that one of the earliest skeletal finds (of an individual who later turned out to be arthritic) was typical, and the cold adaptation that they needed to survive what was then a deep arctic environment. Such adaptations are very rapid in evolutionary terms (consider how, in the space of barely 5000 years, Eskimo and other modern arctic dwellers have physically adapted in just this way, i.e., they are generally short and stocky, but have not yet adapted to low levels of sunlight, as their diet is rich in vitamin D, and so they do not need to synthesise it themselves) and this potential can (must?) exist within any "human" population.
We read about squat, robust Neandertals, and tall, gracefull (let's get some compliments in here...) "modern" humans, but look around and what do we see today? Are we all lithe and gracefull? Not much evidence for it is there? According to a minority of scientists, what we are dealing with is a spectrum, whatever the population, and just because those emerging recently from Africa where hot/dry climate adapted, this is in no way evidence of genetic diversity; consider the same diversity which exists in such human populations today, yet no one seems to be claiming that the typical Ethiopian, or Masai, or Watusi is more "evolved" than their european or chinese counterparts!
About the only distinguishing feature of Neandertals that seem real are, the prominent brow ridge (real) and the large noses (soft tissue, and so only speculation) but are these relevant? Admittedly, prominent brow ridges and big noses are rare, but hardly unknown (anybody remember a Russian premier called Gromyko? He was a prime example of a type that where quite prominent in Russian politics, back in the sixties and seventies, such physiologies are by no means unknown!). Besides, both these features can be due to acromegaly (which arises from over secretion of growth hormone; think "André the Giant" of WWW fame). Could high levels of growth homone have also been an adaption to cold (not forgetting that Neandertals were in Europe and western Asia for at least 250,000years!)?
Looked at dispassionately, the likelyhood is that "modern" humans only made a minor contribution to the current genotype, that the multi regionalism model is valid (and in fact necessary to explain current diversity) and that all the contributing proto humans were in fact just variations of a single species, and could therefore interbreed (just as is the case today, however diverse the individual stocks).
Does this have any bearing on the aspie/Neandertal hypothesise. Yes, it indicates that Neandertals probably influenced all of the current population (though there could possible be less influence among the extreme east asians who became Amerinds, particularly those who now populate Tierra del Fuego, or the oldest existing African populations like the Khoisan, for example; it would be interesting if there was any data on AS among such populations.
Intriguingly, this model also has potential to explain the "establishment" types who are over-influential in modern society, but I'll leave it there for now; coming soon, how to wilfully misinterpret the evidence...
First post: Wild assumptions!
The perceived wisdom is that Neandertals are extinct, and that "modern" humans emerged from africa less than 200,000 years ago. Apart from the logistical implausibility that the decendants of one mother could have displaced the world's other populations of near humans, in so short a time, the mitochondrial argument, as put forward by two protagonists (one of whom is dead) in "the recent African Gensis of humans" (page 54) clearly applies just as well to the more plausible "the multiregional evolution of humans" (page 46). This is a prime example of how even scientists can latch on to a particular "explanation" without regard to the facts (more on this in a following post).
Is this relevant to the supposed Aspie/Neandertal link? Absolutely, as these articles are riddled with the attitude "I'm a modern human, Neandertals are not; they must therefore be inferior!" (sounds familiar?).
Example: That Neandertals where considered shambling ogres was largely due, in part, to the assumption that one of the earliest skeletal finds (of an individual who later turned out to be arthritic) was typical, and the cold adaptation that they needed to survive what was then a deep arctic environment. Such adaptations are very rapid in evolutionary terms (consider how, in the space of barely 5000 years, Eskimo and other modern arctic dwellers have physically adapted in just this way, i.e., they are generally short and stocky, but have not yet adapted to low levels of sunlight, as their diet is rich in vitamin D, and so they do not need to synthesise it themselves) and this potential can (must?) exist within any "human" population.
We read about squat, robust Neandertals, and tall, gracefull (let's get some compliments in here...) "modern" humans, but look around and what do we see today? Are we all lithe and gracefull? Not much evidence for it is there? According to a minority of scientists, what we are dealing with is a spectrum, whatever the population, and just because those emerging recently from Africa where hot/dry climate adapted, this is in no way evidence of genetic diversity; consider the same diversity which exists in such human populations today, yet no one seems to be claiming that the typical Ethiopian, or Masai, or Watusi is more "evolved" than their european or chinese counterparts!
About the only distinguishing feature of Neandertals that seem real are, the prominent brow ridge (real) and the large noses (soft tissue, and so only speculation) but are these relevant? Admittedly, prominent brow ridges and big noses are rare, but hardly unknown (anybody remember a Russian premier called Gromyko? He was a prime example of a type that where quite prominent in Russian politics, back in the sixties and seventies, such physiologies are by no means unknown!). Besides, both these features can be due to acromegaly (which arises from over secretion of growth hormone; think "André the Giant" of WWW fame). Could high levels of growth homone have also been an adaption to cold (not forgetting that Neandertals were in Europe and western Asia for at least 250,000years!)?
Looked at dispassionately, the likelyhood is that "modern" humans only made a minor contribution to the current genotype, that the multi regionalism model is valid (and in fact necessary to explain current diversity) and that all the contributing proto humans were in fact just variations of a single species, and could therefore interbreed (just as is the case today, however diverse the individual stocks).
Does this have any bearing on the aspie/Neandertal hypothesise. Yes, it indicates that Neandertals probably influenced all of the current population (though there could possible be less influence among the extreme east asians who became Amerinds, particularly those who now populate Tierra del Fuego, or the oldest existing African populations like the Khoisan, for example; it would be interesting if there was any data on AS among such populations.
Intriguingly, this model also has potential to explain the "establishment" types who are over-influential in modern society, but I'll leave it there for now; coming soon, how to wilfully misinterpret the evidence...
