“Crime” by Charles Darwin

Charles Darwin (1809-1882) is one of the most important scientists in the history of science and I couldn’t help but be present in my correspondence book Dear Isaac, dear Albert. His great work, for which he is and will be remembered, shows that over time species have changed and processes have unfolded that have affected something as fundamental as our understanding of the relationships that bind our species. Homo sapienswith other forms of animal life that exist or have existed on Earth.

Solving the riddle of nature

Darwin argued that life is like a tree, from the common roots of which different branches have grown; that is, species (related by their relationship to a common stem) that continue to diversify over time, giving rise to other “branches” under the pressure of certain conditions (among them – this Darwin did not know – genetic mutations that occur spontaneously).

After striving to bring together into a grand synthesis the pieces (botany, zoology, taxonomy, comparative anatomy, geology, paleontology, domestic breeding, biogeography…) of the gigantic puzzle that nature is, and inspired by the news that Alfred Wallace had come to similar conclusions albeit not so well founded, in November 1859 he published a book that is part of the most precious treasure available to mankind: Origin of Species. But the path that led him to his theory and book was neither easy nor short.

The finch that changed the world

A pivotal moment in this journey was that in March 1837, when he was studying the birds collected by Darwin in the Galapagos Islands, one of the last stops on the Beagle, the brig in which he sailed on December 27, 1831. Week-long sailing years, that changed his life – John Gould, a taxonomist of the Zoological Society, identified several species of ground finches, whose beaks have adapted to eating insects, cacti or seeds.

Gould then thought that these varieties of finches probably lived on different islands, but he couldn’t be sure because Darwin didn’t label them where he collected them.

Gould’s instructions prompted Darwin to wonder if the similarities between finches on different islands were traces of a common ancestor. Such data prompted Darwin to dare the idea he had in mind: species are unstable.

Darwin’s letter: “It’s like a confession to a crime”

In a letter that Darwin sent on January 11, 1844, to the botanist Joseph Dalton Hooker, he expressed his thoughts clearly:

“I was so impressed with the distribution of organisms in the Galapagos Islands. […] And […] nature of the fossil mammals of America […]that I decided to blindly collect all sorts of facts that might have something to do with what species are. I read tons of books on agriculture and gardening and never stopped collecting data. At last there are glimmers of light, and I am almost convinced (completely contrary to the opinion with which I began) that species are not (like a confession to a crime) immutable. Lord, spare me the Lamarckian nonsense about “tendency towards progress”, “adaptation due to the gradual inclination of animals”, etc., but the conclusions I have come to are not very different from yours, although they are. changes. I think I have discovered (this is a guess!) a simple way in which species are perfectly adapted to various purposes.

“It’s like confessing to a crime,” he said.

They develop, but how?

So, it is one thing to recognize that species change, and quite another to identify some mechanism by which this happens. In other words, a theory was needed to explain evolution; Neither the observations he made while sailing on the Beagle, nor what he later learned about the changes produced by the artificial selection of domestic animals, were enough.

Darwin found the key to the ideas of the economist Thomas Robert Malthus as he outlined them in his 1826 essay. Essay on the principle of population.

In his autobiography, Darwin explained what the job meant to him:

“In October 1838, that is, 15 months after I began my systematic research, I happened to read a book by Malthus on population and how, thanks to my long and continuous observations of the habits of animals and plants, I was well prepared. In order to realize the universal struggle for existence, it immediately occurred to me that under these conditions, favorable options would tend to persist, and unfavorable ones to be destroyed. The result of this will be the formation of new species.

Thus, the door leading to his theory of the origin of species is finally open.

José Manuel Sanchez-Ron, Distinguished Professor of Theoretical Physics. Historian of science. Academician of the RAE Autonomous University of Madrid

This article was originally published on The Conversation. Read the original.