Thursday, February 16, 2006


[evomech] Info wanted on two intriguing 'Lamarckian' experiments

On pages 48 and 49 of "The Great Evolution Mystery" (Secker & Warburg version - page numbers may be different in Abacus or MacDonald editions) Gordon Rattray Taylor wrote:

"Fifty years ago, for instance, one Harry Schroeder conducted an intriguing experiment with the willow-moth caterpillar. This caterpillar places itself on a leaf and rolls the leaf around itself before pupating, fastening it down with a web.

Normally, it starts by drawing the tip of the leaf over itself, but Schroeder, with fiendish cunning, systematically cut off the tips of all the leaves on which caterpillars had taken up position. Sensibly enough, they responded by drawing the side of the leaf over instead.

When these caterpillars had produced another generation, Schroeder found that, of nineteen offspring, four drew the side of the leaf over, not the tip, when their time to pupate came around.

It may be said that this was inheritance of an acquired behavior, not a structure, but there may not be much difference from a genetic point of view, as we shall see.

Perhaps the same might be said of an unique series of experiments by Frederick Griffiths, who placed rats on slowly revolving turntables for periods of up to one and a half years. When the wretched animals were freed their heads constantly flicked in the direction in which they had been rotated, and their eyes flicked also. This flicking automatism reappeared in their progeny."

Both of the above experiments exhibit characteristics consistent with the proposed homeostatic internal evolutionary mechanism I am currently researching. Unfortunately, however, Taylor gives no citations and there are no further references to Schroeder and Griffiths in either the Bibliography or the Sources.

Should anyone comes across any information regarding these experiments - or others of a similar nature - I would be very grateful if you could let me know:

"The Great Evolution Mystery" is no longer in print although used copies are still listed at:


John Latter

Related terms include: Lamarck and Lamarckian

*This is an update of evomech message #43:
Model of an Internal Evolutionary Mechanism:

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