As a biology student in high school and 1st year university I was perplexed by the apparent underlying simplicity of Darwinian Evolution. We were taught of the existance of Lamarcks thoery, given one ultra macro example (giraffe neck) and told how naive and wrong it was; something in the back of my mind remained unfulfilled.
After recently seeing a doco on Prof. Ted Steele, an Australian exponent of Lemarck, i smiled.
Thanks to Lysenko, scientists in Stalin’s Soviet Union were pretty much forced to stick to a Lamarckian model of evolution. Lysenko created a modified form of Larmarckian evolution and it became state policy. Some high-level scientists who advocated Darwin and pointed out Lysenko’s numerous follies were purged.
Well, there are certainly elements of Lamarckian evolution which are obviously true, but there must be some rules which govern which characterists get inheirited, and how, and those must be independent of acquired characterists. Therefore, any Lamarckian evolution must be dependent on Darwinian evolution.
F’rinstance, I remember hearing in school about an experiment that supposedly provided evidence of Lamarckian evolution. I forget the details, but they showed that bacteria grown in high stress conditions (I think it was an antibiotic) had a higher incidence of mutations leading to resistance than a control group, seeming to indicate that the mutations weren’t entirely random. However, they eventually figured out that in high stress coniditions, the bacterial DNA polymerase loosened its proofreading stringency - in other words, it deliberately increased its overall mutation rate. So it was the overall rate that increased, not just the mutation rate in that one necessary gene.
Did the immune system originally evolve through reverse transcriptase-mediated copying of mRNAs back into the germline? Maybe, but I can’t fathom how or why. Antibodies form in part by randomly rearranging a bunch of parts of genes in each immune cell to produce a new “permanent” gene for that cell. The recognition capabilities of antibodies comes from combinations of these parts of genes–the individual parts aren’t necessarily all that great at recognizing anything (if they were individually targeted to specific things, our immune system would have a much much lower range of recognition). So, say this rearrangement somehow gets back into the germline. Now you have an immune system capable of making 1 type of antibody, instead of hundreds of millions. That doesn’t make any sense to me.
But say I’m missing something, and he proves that changes in these antibody genes can move back into the germline. That’s not evidence of Lamarckism being correct–it’s evidence that maybe something resembling Lamarckism works in one system (which has a rather unique method of transcription). It would NOT be a simple logical step to apply what he learns from the immune system to all genes.
The “inheritance” work is over 20 years old and they have never been able to repeat it. The recent work has primarily been in the realm of theoretical speculation regarding a known non-lamarckian (ie, not heritable) somatic mutation pathway.
Lamarckian evolution is rather more involved than simply “inheritence of acquired characters”. True, that was one component by which he attempted to explain the evolution of organisms (he also used “use and disues”, and even allowed a secondary role for adaptation through means similar to Darwin’s natural selection), but other parts of his overall theory, such as the spontaneous generation of one-celled organisms which then evolve upward through the Great Chain of Being, are most assuredly bunk. Showing that in one specific instance, an aquired trait might be established in the germ line does not Lamarckism make. Lamarck’s theory of evolution states that such are the primary processes of organic evolution.
For that matter, Darwin allowed a minor role for the inheritance of acquired traits in his own theories (one of Darwin’s major logical coups was to reverse the relative importance of Lamarck’s processes, making adaptation primary and inheritance of acquired characters secondary, at best). So one could just as easily (and rightly) state that such are still examples of Darwinian evolution.