bzs@MULTIMAX.ENCORE.COM (Barry Shein) (11/03/88)
I don't have a reference handy but basically Lamarck believed that characteristics of a species could be handed down from generation to generation based upon each generations experiences (as opposed to Darwin's "natural selection" where the species changes because only members with certain characteristics survived to reproduce.) For example, a Lamarckian would claim that as lower leaves on trees became scarce giraffes stretched to reach them. This somehow (a mechanism has never been seriously proposed) is transmitted to the offspring in the form of longer necks. A Darwinian would claim that those giraffes who already had longer necks got food and bore offspring, those with shorter necks died of starvation and did not reproduce as much so their genes faded in the population pool. Thus necks tended to get longer over many generations. Mechanisms for this are pretty well established, a combination of random mutation and DNA based genetics. Lamarckian evolution is not accepted by biologists today. There was an article in a recent issue of Nature which apparently (I haven't read it) reported something reminiscent of Lamarckian genetics at a unicellular level. If I remember right bacteria who were starved of certain nutrients "gave birth" to offspring which had (unusual) digestive enzymes able to utilize other nutrients in an environment. I (and others) are not quite sure that this is a proof that there is validity to Lamarckianism, but it is interesting. -Barry Shein, ||Encore||
vespa@ssyx.ucsc.edu (Adam Alexander Margulies) (11/03/88)
Lamarckian genetics: The unique belief that if cut off the tails of
enough rats, you will produce new rats born
without tails.
I said, type it NOW, Adam! || ||Adam Margulies |
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| These are NOT my opinions. They are my dog's. |dlm@cuuxb.ATT.COM (Dennis L. Mumaugh) (11/05/88)
In article <5346@saturn.ucsc.edu> vespa@ssyx.ucsc.edu (Adam Alexander Margulies) writes: > > Lamarckian genetics: The unique belief that if cut off the tails of > enough rats, you will produce new rats born without tails. > > This experiment was done is the USSR during the 1920-30's. Of course any thoughtful person would consider that the Jews and later the Moslems have been doing a similar experiment for some time [in the case of the Jews ~3500 years or 100 generations or more] and have not shown any results. [ This is a tongue in cheek comment about the thought process involved in the theory. Nothing serious intended. ] -- =Dennis L. Mumaugh Lisle, IL ...!{att,lll-crg}!cuuxb!dlm OR cuuxb!dlm@arpa.att.com
bzs@encore.com (Barry Shein) (11/07/88)
There's a lively overview of Lamarckian genetics in the Soviet Union in: Gardner, Martin, "Fads and Fallacies in the Name of Science", Dover, 1957 (originally published by G.P. Putnam as "In the Name of Science"). The chapter is titled "Lysenkoism" after the Russian 'scientist' (I don't believe he had any formal credentials) Trofim Lysenko who popularized Lamarckian genetics in the Soviet Union. It came into such favor that Darwinians/Mendelians were vilified: "'...In 1933 or thereabouts', Muller wrote, 'the geneticists Cheverikoff, Ferry, and Ephroimson were all, on separate occasions, banished to Siberia, and Levitsky to a labor camp in the European Arctic...in 1936 the Communist geneticist Agol was done away with, following rumors that he had been convicted of 'Menshevik idealism' in genetics ... it is impossible to learn the real causes of the deaths of such distinguished geneticists as Karpechenko, Koltzoff, Serebrovsky, and Levitsky. Certain it is, however, that from 1936 on Soviet geneticists of all ranks lived a life of terror." [why was Lamarckianism/Lysenkoism so attractive?...] "Perhaps the most important reason of all is ideological. We have already seen how neatly Lamarckianism fits into the emotion of constructing a new society. Evolution, in Mendelian thoery, is a slow process which operates by means of random, purposeless mutations. The overall result is progress, but a progress in which an individual cannot feel that his own improvements are directly passed on to children. Lysenkoism offers a more immediately attractive vision. Humanity becomes plastic -- capable of being molded quickly by new conditions and individual efforts. Russian children can be taught that the Revolution has 'shattered' the hereditary structure of the Soviet people -- that each new generation growing up in the new environment will be a finer stock than the last. Thus, a foundation is being prepared for a new type of racialism..." We are all, I hope, familiar with how the Darwinians were and continue to be attacked in our own American society. Fortunately it cannot compare to anything that occurred in the Soviet Union during that period in the 20's and 30's described above. I find the study of crackpots a fascinating part of futurology (ie. How are we to distinguish the crackpot from the visionary? How have we done so in the past? Well, not always very well...) -Barry Shein, ||Encore||
mck@hpdstma.HP.COM (Doug Mckenzie) (11/08/88)
I don't have a reference handy but basically Lamarck believed that >Lamarckian evolution is not accepted by biologists today. There was an >article in a recent issue of Nature which apparently (I haven't read >it) reported something reminiscent of Lamarckian genetics at a >unicellular level. >I (and others) are not quite sure that this is a proof that there is >validity to Lamarckianism, but it is interesting. The difference is that in unicellular reproduction, the entire genetic material is inherited by "offspring". In multicellular organisms, specific germ cells contain the transmitted genetic material. So, in the single cell case, any change to the organism's genetic material must be delivered to offspring (i.e. mutation of the organism results in a mutated child). In multi-cellular critters, "mutations" to the organism (e.g. blacksmiths acquiring strong arms) have no effect on children. Only germ cell mutations propagate. Doug McKenzie HP/HP-UX Support