Charles Darwin
Birth:February 12, 1809 Shrewsbury, England
Died:April 19, 1882 (aged 73) Downe, England
Nationality:United Kingdom
Profession:British biologist
Distinctions:Wollaston Medal 1859
Copley Medal 1864
Family:Erasmus Darwin, his grandfather
Robert Darwin, his father
Emma Wedgwood, his wife
George Darwin, his son
Charles Robert Darwin (February 12, 1809 in Shrewsbury - April 19, 1882 in Downe) was a British biologist. He developed the first theory of a biological mechanism of evolution, natural selection, which explains the diversification of life through a slow process of change through adaptation.
Fifth of six children of Robert and Susannah Darwin (née Wedgwood), and grandson of Erasmus Darwin (1731-1802) and Josiah Wedgwood, Charles Darwin studied medicine in Edinburgh in 1825. In 1827, disgusted by dissection and brutality of the surgery of the time, he left medical school where he was however marked by Robert Edmond Grant (1793-1874) and Jean-Baptiste de Lamarck (1744-1829).
His father, worried about his son's academic failure, and fearing that he would become a fanciful, enrolled him in Cambridge to study theology, in the hope that Charles would become a pastor. There he fell under the intellectual influence of scientific minds such as William Whewell and John Stevens Henslow (1795-1861). His interest in collecting beetles and the encouragement he received from his cousin William Darwin Fox pushed him towards natural history.
When he finished his studies, Henslow recommended him as a traveling companion to Robert Fitzroy, the captain of the HMS Beagle, who was preparing to leave for a five-year expedition to map the coast of South America.
Before leaving, Charles Darwin spent a few weeks with geologist Adam Sedgwick mapping strata in Wales. It is notable that, apart from a few courses taken in Edinburgh, this was his only experience of formal geological study.
Charles Darwin took the opportunity to study the geological properties of the continents and islands visited during this expedition, as well as a multitude of living organisms and fossils. He thus travels through Tierra del Fuego, the Falkland Islands, Chiloé Island, the Andes, the Galapagos Islands, Tahiti, New Zealand, Australia, Tasmania, Mauritius and Cape Town.
On his return from his trip, on October 2, 1836, Darwin analyzed the very numerous specimens he had brought back and noted similarities between the fossils and the living species in the same geographical area. In particular, he notices that each island has its own type of turtles and birds, which differ slightly in appearance and diet, but are otherwise quite similar, especially in the case of specimens from the Galapagos Islands. He then developed the theory that, for example, each kind of turtle originated from the same species, each being adapted differently to life on different islands. In doing so, he abandons the idea of the divine creation of species.
In 1837, he formulated his thoughts on the modifications and development of species in his Notebook on the transmutation of species, in accordance with Charles Lyell's Principles of Geology. On September 28, 1838, he read Thomas Malthus' Essay on the Settlement Principle, which predicted that the size of a population was limited by the amount of food available, which made him reflect on the problem of the struggle for survival.
In 1842, Darwin formulated his theory in the form of a "schematic", and in 1844 he wrote a 240-page essay containing an expanded version of his early ideas on natural selection. Between 1844 and 1858, when he presented his theory to the Linnean Society in London, Darwin made numerous modifications to it.
Darwin married his cousin Emma Wedgwood in 1839 and became a Fellow of the Royal Society of London. After living for several years in London, the couple eventually moved to Down House, Downe in Kent (which is now open to public visits). Charles Darwin and his wife had ten children, three of whom died in infancy.
Between 1839 and 1843, his work Zoology of the Voyage of H.M.S. Beagle is published in 5 volumes. Between 1840 and 1858, he published several works, while working on his theory:The Structure and Distribution of Coral Reefs (1842), a work on the geology of atolls and coral reefs. He was the first to understand the organic origin of atolls and the primordial role of corals. He also studies South America, volcanic islands, cirriped crustaceans (1851-1854). Finally, he works on the geographical distribution of organisms, and Lyell convinces him to publish his theory. He was awarded the Royal Medal in 1853.
On July 1, 1858, Charles Darwin read a paper before the Linnean Society in London, the same day as Alfred Russel Wallace, who had independently developed a similar theory. Like Darwin, Wallace had spent many years observing the diversity of life, and had come to similar conclusions. Having decided to publish, he chose to submit comments to a renowned biologist who encouraged him to complete his work.
Darwin's On the Origin of Species by Natural Selection was published a year later (1859), and aroused enough interest that the publisher's stock sold out on the first day.
In early 1860, the British Royal Academy of Sciences, drawing up its annual scientific report on 1859, described it as a "dull year, in which not much happened".
In his next major works, Variation in Domesticated Animals and Plants (1868), The Descent of Man and Selection by Sex (1871), and The Expression of the Emotions in Men and Animals (1872), Darwin developed many topics introduced in The Origin of Species.
Despite some criticism (for example, in the first edition of The Origin of Species, Darwin still assumes "cumulative effects of training" from generation to generation in pointing dogs), the value of Charles Darwin's work is recognized by the scientific community. He became a member of the Royal Society of London in 1839 and of the French Academy of Sciences in 1878. He received the Wollaston Medal in 1859 from the Geological Society of London. He was awarded the Copley Medal in 1864.
He died in Downe (Kent), on April 19, 1882, and is buried in Westminster Abbey.
He received special recognition in 2000 when his image appeared on the Bank of England's 10 pound note, replacing Charles Dickens. His impressive and supposedly hard-to-fake beard was reported to have been a factor in this choice.
Before Darwin
Before the 19th century, the common theory of species extinction was called catastrophism, according to which species died out due to catastrophes, followed by the formation of new species ex nihilo (created from nothing). Extinct species were found in the form of fossils. New species were considered immutable. This theory was consistent with the Flood episode in the Bible. In the early 19th century, several new theories began to challenge catastrophism. One of the most important of them was developed by Jean-Baptiste de Lamarck.
He observed that every new generation inherited the characteristics of its ancestors. He suggested that features and organs were enhanced by repeated use and, conversely, were diminished or suppressed by non-use in each individual, who passed on these enhancements and suppressions directly to their descendants.
In 1830, the British geologist Sir Charles Lyell refuted the theory of catastrophism, but held to that of the immutability of species. Lyell founded the theory of uniformitarianism, which stated that the Earth's surface changed slowly through eons, subject to constant forces.
The structure of Darwin's theory
Darwin's theory of evolution states that all individuals in a population are different from each other. Some of them are better adapted to their environment than others and therefore have a better chance of surviving and reproducing. These advantageous characteristics are inherited by subsequent generations and over time become dominant in the population (see Figure 2). This gradual and continuous process results in the evolution of species. The main points of the theory are:
1. There is an evolution.
2. Evolutionary changes are usually gradual, taking thousands to millions of years.
3. Natural selection is the primary mechanism of evolution.
4. This selection has two components:
1. survival selection
2. sexual selection, i.e. ability to find a partner:an individual remarkably adapted for survival and who would not be at all attractive to the opposite sex will not transmit his heritage (hence the emergence of the tail of the peacock, for example, although this greatly handicaps it vis-à-vis possible predators).
5. All species alive today derive their origin from a single life form through a branching process called speciation.
Welcoming Darwin's theory
After the publication of Darwin's work, evolution by natural selection was widely discussed, even denigrated (see figure 3), particularly in the religious and scientific communities. Although Darwin was supported by some scientists (for example, Thomas Henry Huxley, Ernest Renan or Ernst Haeckel who popularized him very early in Germany), others were reluctant to accept his theory because of the unexplained ability of individuals to transmit their abilities to their descendants. This last point was however studied at the same time by Gregor Mendel, but it does not seem that the two men communicated together. Even with Mendel's laws, the underlying mechanism remained a mystery until the existence of genes was discovered.
In 1874, theologian Charles Hodge accused Darwin of denying the existence of God by redefining man as the result of a natural process rather than the creation of God. Darwin, despite being the son of a pastor, had already (Mrs Darwin points out in her correspondence) stopped believing in the existence of a benevolent god when he had discovered the mechanism of reproduction of the ichneumon wasp, whose larvae develop by "devouring their living prey from the inside" while scrupulously respecting its vital organs! Victor Hugo was strongly opposed to Darwin's theory.
The biologist and geographer Pierre Kropotkine will define in 1906 that mutual aid is also a factor of evolution, as much in non-human animals as in humans.
While the Vatican now admits that the Darwinian mechanism is, in its own words, “more than a hypothesis,” some Protestant fundamentalist circles, especially in the United States, are fighting the Darwinian theory of evolution. However, this movement is only very marginally observed in Europe.
Darwin's theory is now confirmed by comparing the DNA of different organisms, which shows their genetic proximity. We are even working to establish a new classification of living organisms whose taxonomy would be organized according to the genetic distance between species and not the characteristics of the phenotype. However, this method requires computer time which increases very quickly with the number of species considered.
Contrary to popular belief, Darwin did not "discover" evolution, which has been accepted by many since the beginning of the 19th century. On the other hand, he brought the first coherent theory on how evolution takes place (by the mechanism of natural selection). Other important aspects of Darwin's theory were:common origin, sexual selection, progressiveness and pangenesis. It is important to remember that Darwin's version of natural selection differed from that presented by Wallace in that it asserted that natural selection occurs continuously, whereas Wallace argued that selection occurs only when the environment was changed.
This opposition existed in a slightly different form between Stephen Jay Gould, who defends a theory of punctuated equilibria, and Richard Dawkins who does not agree with this point of view.
Certain out-of-context interpretations of Darwin's theory, neither intended nor intended by him, have had important spin-off effects. Two have proven to be socially catastrophic:
* Social Darwinism interprets Darwin's sentences expressing probability ("more fit organisms must eliminate in the long run the less fit ones") as categorical imperatives.
* Nazism, parallel to social Darwinism , also stemmed from a misunderstood Darwinism, and perhaps also from the psychological trauma caused by this theory in many minds. For example, if many lines were condemned not to survive, some preferred that "their" line was not of these.
An ambiguous formulation by Darwin may have had some responsibility for these deviations:he indicates on several occasions that the most suitable forms must eventually replace the less suitable, without the verb used (ought to) being able to be clearly identified. as the expression of a "probability" or on the contrary of a "moral imperative".
The future will tell if the following hypotheses are more fruitful:
* Richard Dawkins and Daniel Dennett envision natural selection of memes (elementary ideas) reproducing and combining in minds as genes reproduce through organisms.
* Physicist David Deutsch, in his book The Fabric of Reality, considers the universe we know as the effect of a series of natural selections in the universe of possibilities.
Darwin Quotes
"The fundamental conclusion at which we have arrived in this work, that man is descended from some lower form of organization, will, I regret to think, be very disagreeable to many people. (Charles Darwin, The Descent of Man and Sex-Related Selection, Volume II, page 426)
“I for my part would as much like to descend from the heroic little monkey, who braved his dreaded enemy to save his guardian; or of the old baboon who, descending from the heights, triumphantly carried off his young comrade after having snatched him from a pack of astonished dogs - than of a savage who delights in torturing his enemies, devotes himself to bloody sacrifices, practices the infanticide without remorse, treats his women like slaves, ignores all decency and is a prey to the grossest superstitions. » (Quoted by André Pichot in Pure Society page 105)
“During the day, I was entertained by the dexterity with which a gaucho forced a wayward horse to cross a river. He took off his clothes and jumping on his back, went with him into the water until he lost his footing. Then sliding down the rump, he gripped the tail tightly, and every time the horse turned around, the man scared him by spraying water on his head. As soon as the horse regained footing on the other side, the man mounted him and sat down bridle in hand, before he had regained the bank. A naked man on a naked horse is a pleasant spectacle. I never imagined that the two animals could adapt so well to each other. (Horses in the Art, Photography and Literature of Lorraine Harrison ed. Evergreen (2000), page 92).
"We have seen that the senses and intuitions, the different emotions and faculties, such as love and memory, attention and curiosity, imitation, reason, etc., which man boasts of, can be found in their infancy, or even fully developed in the lower animals. The animals, of which we have made our slaves, which we do not want to consider as our equals. (source:"From the Origin of Species by means of Natural Selection".)
“The classification of organic forms, functions, and diets has shown evidently that the normal food of man is vegetable like that of anthropoids and apes, that our canines are less developed than theirs, and that we We are not meant to compete with wild beasts or carnivorous animals. (source:"From the Origin of Species (fr) [2] by means of Natural Selection".)