Lamarck proposed a “use and disuse” theory of how in animals could change over time. As a child I remember the pictures of the short-necked giraffe morphing to a long-necked giraffe so that it could reach leaves for food on a higher branch. Wallace (1891, 3-4) said that Lamarck’s theory basically failed by not showing HOW generational animals “could have preserved their numerous slight and apparently purposeless differences from each other.”
Larmarck, as did Darwin and Wallace, needed more information on DNA and how it works. Fast forward to now. We now know it is not just simply the DNA that affects the organism, but how the DNA is manipulated. Apparently, DNA can be “locked and unlocked” with DNA methylation and histone acetylation. This is the domain of epigenetics. For example: The Overkalix study showed how that diet over generations affected prevalence (or lack of) of disease in subsequent generations. It may be that what one does, eats, acts upon right here and right now, has the possibility of affecting future offspring. Kinda sounds Lamarckian.
Lamarck was on to something. It’s like he knew it was there, and did the best he could to explain what he thought. Stepping stones. The idea seemed right for a minute, was then ridiculed and later dusted off for a re-look. Like what I am doing right now.
I think I am guilty of rejecting an entire concept because it “doesn’t all fit.” What if part of it seems right?
Wallace, Alfred. Darwinism: An exposition of the Theory of Natural Selection with some of its applications. London: Macmillan and Co., 1891.