Tl;dr: This post features my (thus far) favorite quote that I have found when doing historical work on experimental evolution. In his speech/article, Liberty Hyde Bailey argued that the truth of evolution had already been demonstrated… centuries ago as well as in the present day, not by the academic elite, but by those involved in the cultivation of fruits, vegetables, and flowers. For Bailey, the domestication of plants and animals was a form of experimental evolution.
In 1891, the French Darwinian Henry de Varigny, mentioned in my previous post, called for an “experimental evolution.” He thought experimental work could demonstrate the reality of evolution in real time, so as to convince those who remained creationists that Darwin was generally right. Additionally, citing breeders as a kind of ‘experimental evolutionist,’ he argued that there would be practical and economic benefits to its pursuit. Thus, for de Varigny, experimental evolution would push evolution towards acceptance while creating societal benefits.*
While de Varigny’s influence remains unclear to me, especially with regard to his proposal for a station of experimental evolution,** at least one scientist responded, arguing that breeders had already shown that evolution was real.
Liberty Hyde Bailey, a professor of horticulture at Cornell University and an all-around important public figure (and poet, apparently), responded with an address to the Massachusetts Horticultural Society, later published in The American Naturalist, titled “Experimental Evolution Amongst Plants.” Skipping to the juicy part, Bailey ends his address with this bombshell of a quote:
“He [everyone] knows that nearly every plant which has been long cultivated, has become so profoundly and irrevocably modified that people are disputing as to what wild species it came from. Consider that we cannot certainly identify the original species of the apple, peach, plum, […][***] and nearly or quite a hundred other common cultivated plants. It is immaterial whether they are called species or varieties. They are new forms. Some of them are so distinct that they have been regarded as belonging to distinct genera. Here is the experiment to prove that evolution is true, worked out upon a scale and with a definiteness of detail which the boldest experimenter could not hope to attain, were he to live a thousand years. The horticulturist is the only man in the world whose distinct business and profession is evolution. He, of all other men, has the experimental proof that species come and go.”
“… whose distinct business and profession is evolution.” Love it!
Despite the power of his argument, we all know creationism has yet to disappear from American society. In fact, Bailey’s style of argument is still used over one hundred years later to teach evolution to the public and to confront creationists.
For instance, Jerry Coyne, at his website Why Evolution Is True, used the brassica vegetables and dog breeds as examples of the power of artificial selection in a post attacking intelligent design. David Mindell’s The Evolving World contains several more examples of this evolved diversity of plants and animals through human domestication.
[I was hoping to embed the clip from the second episode of the new Cosmos with Neil deGrasse Tyson where he discusses the evolution of dogs, but apparently most of the formerly available clips have been removed for the sake of making people buy the blu-ray/DVDs. Boo.]
Returning to the history, Bailey spent the rest of his article (~8 pages) arguing with those who claim that the new horticultural varieties are not actually distinct species. He thought such claims were unfounded, premised upon a divide between humans/artifice and nature that does not exist. Operating under something like a morphological species concept, one in which Darwinian selection eliminates transitional forms, he argued that the remarkable differences in form between cultivated plants and their ancestors is sufficient for demarcation. But whether or not Bailey’s argument survives today, with the plethora of competing species concepts that biologists have generated since the 1890s, I do not know.
What I find important is Bailey’s link of horticulture and agriculture to experimental evolution. Before stumbling upon this paper, I had already wanted to incorporate the breeding arts/sciences into experimental evolution in some way, given that breeders are actively shaping populations of organisms to some end, adapted to the environment of human wants and needs. However, such a link would be my own interpretation of history rather than a link that emerged from the historical actors themselves. Thankfully, Bailey makes the link for me! Additionally, it was shortly afterward that I realized I did not need Bailey due to the fact that several biologists who considered themselves plant breeders engaged in experimental evolution themselves: most importantly, Hugo de Vries and Wilhelm Johannsen (and those who worked with animals, like Raymond Pearl and x Hagedoorn). Thus, I think I can add plant and animal breeders into the mix of experimental evolutionists, as long as I am careful with regard to intentions and practice.
In any case, I just wanted to publicize that quote. I am not sure if I will ever find another one quite like it!
* Perhaps more important though, de Varigny thought experimental evolution would resolve the crisis in which the field of evolution had fallen, frequently called “the eclipse of Darwinism,” a period marked by a number of competing theories of evolution. Experiments would show which theories were true and which were false. Over time, the need to demonstrate evolution disappeared as the beneficial aspects of practical utility and scientific advancement beceme the raison d’etre of experimental evolution. However, these reasons were not on Bailey’s radar for his article, so I will leave these topics for another time.
** In 1904, the Station for Experimental Evolution is established at Cold Spring Harbor, but I do not know if de Varigny’s book had any influence upon this. Additionally, a more prominent Darwinian at the time, G.J. Romanes, circulated a document also calling for such an institution. Whether or not he was influential I also do not know.
*** For the sake of full disclosure, the ellipsed part of this paragraph is merely a continued list of cultivated plants. It does not contribute substance to his point other than to add to the rhetorical effect of demonstrating the sheer volume of plants brought under domestication, and hence, ‘experimentally evolved.’