The Inheritance of Acquired Characteristics 1
A tree on the Greek island of Kos
The most famous son of the Greek island of Kos – from where I have just returned – is the eponymous author of the Hippocratic Oath. I visited (possibly a descendant of) the tree which Hippocrates supposedly taught under:
It did not look very well – despite the illustrious history of its forbearer.
While his famous oath or, at least, modernized versions thereof survive to this day1, many of Hippocrates’s ideas on the workings of the human body have aged rather worse than his tree.
In an essay on “Airs, Waters, and Places” and their influence of health, he writes:
I will leave out the minor distinctions of the various races and confine myself to the major differences in character and custom which obtain among them. First the Macrocephali; no other race has heads like theirs. The chief cause of the length of their heads was at first found to be in their customs, but nowadays nature collaborates with tradition and they consider those with the longest heads the most nobly born. The custom was to mould the head of the newly-born children with their hands and to force it to increase in length by the application of bandages and other devices which destroy the spherical shape of the head and produce elongation instead. The characteristic was thus acquired at first by artificial means, but, as time passed, it became an inherited characteristic and the practice was no longer necessary. The seed comes from all parts of the body, healthy from the healthy parts and sickly from the sickly. If therefore bald parents usually have bald children, grey-eyed parents grey-eyed children, if squinting parents have squinting children, why should not long-headed parents have long-headed children? But in fact this does not happen as often as before, because the custom of binding the head has also become obsolete through intercourse with other peoples.2 [my emphasis]
Thus here we have a very early proclamation of the notion that characteristics acquired in life can be inherited by future generations.
Now this notion is more closely associated, in most people’s minds, with the French naturalist Jean-Baptiste Lamarck. Indeed, “Lamarckism” – a term apparently first coined in this sense by Alpheus Packard in 18843 – has become a synonym for the theory of the inheritance of acquired characteristics. This association seems a little unfair as Lamarck’s (more novel) claims were that species are mutable and that “time and favourable conditions are the two principal means which nature has employed in giving existence to all her productions”4. In other words, a statement of the basic facts of evolution.
While it is true that Lamarck believed that the mechanism behind evolution was “Lamarckian” in nature, belief in such a mechanism had been commonplace throughout history (as my reference to Hippocrates suggests) and “Lamarckian” claims were even endorsed in Darwin’s Origin of Species:
I have now recapitulated the facts and considerations which have thoroughly convinced me that species have been modified, during a long course of descent. This has been effected chiefly through the natural selection of numerous successive, slight, favourable variations; aided in an important manner by the inherited effects of the use and disuse of parts; and in an unimportant manner, that is, in relation to adaptive structures, whether past or present, by the direct action of external conditions, and by variations which seem to us in our ignorance to arise spontaneously.5 [my emphasis]
And yet today, “Darwinism” (or, at least, “Neo-Darwinism”) is often contrasted with “Larmarckism” in discussions of the inheritance of acquired characteristics. Modern Darwinism has very little time for claims such as Lamarck’s that the peculiar shape and size of the giraffe is the result of its habit “long maintained in all its race” of making constant efforts to reach the leaves of trees6.
But more interesting, I submit, than the historical question of who thought what when (though that is interesting) is the modern one of who is right, and whether there is any truth at all in Lamarckism – an idea that refuses to die. And in order to answer that question, we shall first have to understand the “Darwinian” alternative explanation as to how evolution occurs …
Next: “The Last Lamarckians”
Green, B.; Use of the Hippocratic or other professional oaths in UK medical schools in 2017: practice, perception of benefit and principlism; BMC Res Notes 10, 777 (2017). [link]
ed Lloyd, G. E. R.; trans Chadwick J., Mann, W. N., Lonie, I. M., and Withington, E. T.; Hippocratic Writings; London; Penguin; 1983. [link]
Pfeifer, E. J.; The Genesis of American Neo-Lamarckism; Isis, 56(2), 156–167 (1965). [link] In which Pfeifer states that Packard coined the term "neo-Lamarckianism" in 1884 to describe such ideas, “though he [Packard] ultimately recommended the shorter form of the word”. If, however, you consult the cited work: Packard, A.S., Lamarck, the Founder of Evolution: His Life and Work; New York; Longmans; 1901. [link], , Packard actually uses the term “Neolamarckism”.
University of California Museum of Paleontology; Jean-Baptiste Lamarck (1744-1829); U C Berkeley; (1998). [link]