Darwin and Mendel
by
Harold Richman
Charles Darwin and Gregor Mendel were contemporaries. Darwin lived from 1809 to 1882, and Mendel from 1822 to 1884. Darwin published his Origin of Species in 1859 and Mendel published the results of his experiments on inheritance in 1866. Unfortunately they never met. They were like ships that pass in the night (in one case within fifty feet, and in another within two inches! I'll explain later.) This was regrettable as each would have been of great assistance to the other in his work.
Darwin made his famous five-year voyage on the HMS Beagle from 1831 to 1836. It was during the stop at the Galapagos Islands that he started to formulate his Theory of Evolution. He observed that there were fourteen different species of ground finches, each adapted to feed on a certain type of food. One of the species, called the Woodpecker Finch, is one of the few animals that uses tools; it uses cactus spines to extract larvae from cacti and trees. When he first observed the finches, Darwin thought that they were just different varieties of the one species. However, when he returned to England and showed the specimens he had collected to an expert ornithologist, he was told they were actually different species.
There was a 23-year gap between his formulation of the Theory of Evolution and the publication of his book, On the Origin of Species by Natural Selection. He would still have delayed publication if not for the fact that Alfred Russell Wallace, another naturalist, had sent him his manuscript in which he had arrived at the same conclusions.
There were two main reasons why Darwin delayed publishing his discovery. The first was his concern about the reaction of the church to his Theory of Evolution. Darwin had studied for Holy Orders in the Church of England, and he knew the position of the church, i.e. that all species were fixed and unchanging. The controversy still carries on to the present, and in my opinion it is due to the fact that we still call it Darwin's Theory of Evolution.
During one of the lectures I attended on evolution, I questioned the professor as to why we still call it a theory when it has been proven to be a fact. He said that 'theory' does not mean that it is not a fact, and according to Webster's Dictionary he is correct - "the-o-ry 1. a coherent group of general propositions used as principles of explanation for a class of phenomena: Newton's theory of gravitation". But in the next definition the following appears: "a proposed explanation whose status is still conjectural, in contrast to well-established propositions that are regarded as reporting matters of actual fact". Most people consider the second definition to be the correct one.
(The proponents of Creationism claim that since evolution is only a theory, they have an equal right to teach their theory in the schools. They have actually been successful in some states in the United States, and Creationism is taught in the schools at the present time. At the beginning of the term our professor tried to be very diplomatic as he did not want to offend anyone who held strong religious views, especially since the University of Winnipeg was originally United College and was affiliated with the United Church of Canada.)
The second reason Darwin delayed publication was a problem he had not been able to solve. His Theory of Evolution was based on the premise that every species had enough variation between individuals to allow some individuals to adapt more readily to changes in the environment. This is what is meant by "survival of the fittest". Darwin did not coin this phrase himself. It was first used by Herbert Spencer, an ardent supporter of Darwin. When we hear this phrase we visualize two male animals fighting to determine who will mate with the females to perpetuate the genes of the fittest. This is not what Darwin had in mind. He included all animal and plant life. When conditions change, there are certain individuals that are more adaptable to the new environment and they will survive and produce offspring with the same characteristics. After a period of time, most of the population will have these desirable characteristics. Darwin's main difficulty in convincing his peers was that he had no explanation how this variability arose. If he had known about Mendel's work (specifically Mendel's Law #2) he would have had the answer.
Darwin is considered by many as mainly a keen observer of nature, but in fact he also carried out experiments, whenever he could, to confirm his theories. He was very interested in heredity and studied the pedigree records of the Pigeon Society to see if he could find any laws that govern inheritance, but was unsuccessful. He then tried to crossbreed plants and by a remarkable coincidence chose the garden pea just as Mendel had done. He even found the three-to-one ratio between two variations of a particular characteristic, but unlike Mendel he was unable to find the explanation.
Mendel, on the other hand, was unsuccessful in convincing his contemporaries of the significance of his discoveries because no one believed that mathematics could be applied to nature. He corresponded with one of the foremost naturalists, Naegeli, who asked Mendel to see if he could reproduce the same result with another plant that he himself had experimented with called Hieracium. Mendel tried for five years but was unable to obtain the same results and eventually gave up his research. It is only in recent times that scientists have found that Hieracium was an exceptional case. This species produces seeds by a pollen grain fertilising an egg cell, but also by apomixis (some of the egg cells are formed with two sets of chromosomes and therefore can develop into a seed without fertilisation. These seeds will produce plants that have all the same characteristics as the plant that produced the flower).
Mendel presented his findings to the Brunn Natural History Society; it was published in their Journal in 1866. 114 copies were sent to various scientific societies- two in Great Britain, the Royal Society and the Linnean Society. Darwin presented his Theory of Evolution in a joint lecture with Wallace at the Linnean Society. Darwin was a member of the society and attended meetings and probably used the library. It is therefore very likely that he was within fifty feet of the Journal that contained the results of Mendel's research.
In reading about Mendel, I came across another amazing incident. A scientist named J.G. Romanes was preparing an article on hybridism for the 1881 edition of The Encyclopaedia Britannica. He enlisted Darwin's assistance in order not to omit any worthy hybridists. Darwin suggested he read a book by Focke called Plant Hybridisation published in 1880. Darwin sent him his own copy. Romanes found Mendel's name in the historical section and included Mendel in his list of hybridists. However, he missed reading the section on Leguminoceae in which Mendel's experiments and conclusions were outlined. The reason we know that he did not read this section is that the pages were still uncut. When books are published, the pages are printed on large sheets containing eight pages which are then folded and bound into a book. In Darwin's time the publisher did not cut the pages at the fold; this was left to the reader. Romanes returned the book. We also know that Darwin did not read this section as the pages remain uncut to this day. So we could say that Darwin was within two inches of the answer to his quandary of why variations occur in a species.
PostScript
Recently I returned to the Linnean Society in London and asked the librarian, Mrs. Douglas, if they still had the journal containing Mendel's results, sent to the Society in 1866. She unlocked a bookcase behind the desk and pulled out the journal. I was amazed that it was still on file. Of course the article was written in German so I couldn't understand it completely, but I could follow the gist of what Mendel wrote. The convention of using a capital letter to denote the dominant characteristic and a lower case of the letter to denote a recessive characteristic was used in the article. This convention is still in use today. (Recently I downloaded an English translation of Mendel's paper from the Internet.)I also asked Mrs. Douglas if they had the book by Focke. She advised me that Darwin's books were now at Cambridge University, but she did find a volume that contained a list of all Darwin's Books. I found the Focke book listed followed by a number of symbols indicating: CUL=Cambridge University Library, S-signed, I-inscribed, and P=pages uncut!