SCHOLTES@ascf.sdr.slb.COM ("SCHOLTES%ASC@SDR.SLB.COM") (10/24/88)
From: ASCF::SCHOLTES "SCHOLTES%ASC@SDR.SLB.COM" 18-OCT-1988 15:13:58.63 To: ASC::SDR::IN%"king@kestrel.ARPA" CC: SCHOLTES Subj: RE: test Why is natural selection the dominant evolutionary mechanism of life? I recently read of some cases of Lamarckian genetics (inheritance of acquired characteristics) at the microbial level. While pondering the dangers of successively more dangerous computer virii, looming threat of self-replicating nano-machines, and the inefficiencies of genetic algorithms, it struck me that being able to pass on acquired characteristics should have a vast competetive edge over Darwinian selection, and the rate of change of a population using that mechanism would be vastly higher, with a corresponding decrease in wasted lives (failed random variations). So, why hasn't it happened naturally? Is it infeasible in natural bio- chemical systems? Is it fundamentally flawed? That possibility would have serious implications for human social change, which is basically Lamarckian, rather than Darwinian. Soon it will be technologically feasible for people to meddle with the genetic composition of their own offspring (eugenics has dread connotations because former proponents have tried to modify the gene pool by selection; direct genetic engineering is a different proposition). So it is possible that human genetic evolution will soon be affected by social evolution. Have there been any fairly recent studies of Lamarckian population genetics? ----------------------------- Mike Scholtes Schlumberger Well Services Austin Systems Center disclaimer: I'm human.
mwm@VIOLET.BERKELEY.EDU (Mike Meyer, I'll think of something yet) (10/26/88)
>> So, why hasn't it [lamarckian evolution] happened naturally? >> Is it infeasible in natural bio-chemical systems? Obviously not, if the claims you quote about seeing it microbial level. >> Is it fundamentally flawed? Probably not, as any change you can apply to an organism can be made via genetic alterations. I think the problem can be found right here: >> it struck me that being able to pass on acquired characteristics should have >> a vast competetive edge over Darwinian selection, and the rate of change of >> a population using that mechanism would be vastly higher, with a corresponding >> decrease in wasted lives (failed random variations). Considering that _natural_ changes to living creature tend to be mostly harmfull to that creature, I don't see why you think there would be fewer wasted lives. Any animal that lost a leg would wind up with 1/2 (is that a dominant or a recessive? :-) it's children being without that leg, etc. Seems those would be "wasted lives" in the sense of not aiding the evolution of the species. It's obviously possible for evolutionary changes to happen to fast - if every member of a species changes, the species vanishes in one generation. The question then becomes, what percentage of the population do you want to randomly mutate looking for beneficial mutations. The answer also obviously depends on the frequency of beneficial mutations among all mutations. Given the way evolution works, I wouldn't be surprised if the mutation rate is close to optimal for the radiation levels on earth at some early period of history. And that could well explain why we don't see lamarckian evolution at a macroscopic level: the number of mutations per generation is way to high for it to be an efficient method of species evolution. Given _controlled_ mutations, though - everything changes. There, Lamarckian evolution is a major advantage, as it's much easier to work with a being than with it's DNA repressentation. <mike
jjw@celerity.UUCP (Jim ) (11/01/88)
In article <8810242341.AA07687@multimax.ARPA> SCHOLTES@ascf.sdr.slb.COM ("SCHOLTES%ASC@SDR.SLB.COM") writes: >Why is natural selection the dominant evolutionary mechanism of life? Because that's the simplest mechanism -- what works stays around, what doesn't work goes away. "Lamarkian" genetics would first have to pass that test (i.e. it would have to work in order to stay around). >So, why hasn't it happened naturally? Actually, it has, it just doesn't use the genetic mechanisms. The genetic mechanisms work best by encoding the ability to change (like fur color change with seasons) rather than by leaving the latest state of the parent as the next state of the offspring. >... human social change, which is basically Lamarckian ... BINGO! -- intelligence and intra-species communication(language) are naturally evolved mechanisms which allow a species to learn how to cope with its environment and to pass the knowledge on to offspring.