Apr 20, 2009
2009 is both the 200th anniversary of Charles Darwin’s birth and the 150th anniversary of the publication of his book On the Origin of Species by Means of Natural Selection. A double reason to celebrate a decisive step in the progress of knowledge over religious reaction.
In 1809 when Darwin was born, “public opinion” in the western countries agreed that the biblical creation story explained the creation of the earth and the living beings that inhabit it. The church maintained that the earth was six thousand years old. While the majority of naturalists and other “scholars” believed that God was the great architect of the earth and all things, there were some whose observations, particularly of fossils, led them to call in question the dogma of creation and the immutability of species.
Among those who today are called evolutionists, but were called then “transformationists,” was Buffon, born a hundred years before Darwin. In the 1700s, he defended the idea that the earth and living beings had been transformed over the course of time. He worked to show that the earth was much older than the professors of theology presumed, and this assertion caused him no end of trouble.
Lamarck, one of Buffon’s disciples, later elaborated this idea of transformation. And in 1809 Lamarck set out his theory that species, under the pressure of the environment, transform themselves in order to be better adapted to their surroundings, and that they transmit these transformations to their descendants. He was the first to formulate an explanation of transformations in relationship to the environment.
Opposed to the “transformationists” were those who thought that all species remained as they had been created and reproduced identically, “fixed” through time. Cuvier was one of the most famous. When Darwin was born, Cuvier was a prominent 40-year-old professor who specialized in paleontology, the study of fossils. Some of the fossils he studied showed that species different from modern species had existed earlier. To explain this, Cuvier put forward his “theory of catastrophes,” that the earth had experienced catastrophes, of which the flood was the most recent. In the course of these catastrophes, some species disappeared, to be replaced by others that came from other places. The biblical legend was saved, all the animals were the product of the creation and only those saved by Noah survived.
Throughout the early nineteenth century, the theories of those who thought everything remained fixed clashed with those of the “transformationists”. What Darwin contributed and what soon allowed him to settle, prove and convince was an impressive quantity of observations and facts – thousands of specimens of plants, animals and fossils gathered during his five year trip around the world aboard the Beagle.
Darwin was 22 when he left on his three-masted ship, sent out to chart the coasts of South America. He was the son of a doctor and had spent three years studying medicine at the University of Edinburgh before abandoning his studies, lacking a real calling. Then he studied theology at Cambridge and became an Anglican pastor, in order, he said, to have time to devote to his passion for natural history. It was a bit of an accident that he had the chance to sail with the Beagle as a naturalist while still a believer in the “natural theology” taught at Cambridge, which held that the marvelous harmony of the world and nature could only be explained by a “divine design.”
The long voyage around the world and above all his many discoveries ended up bringing him to question all that. He had brought The Principles of Geology on board with him. This was a book published by Charles Lyell, a geologist who opposed catastrophism and for whom the earth, far from having been created in a time marked by catastrophes, was formed and transformed over the course of time by the continual and progressive effects of natural causes like erosion and volcanic eruptions. A stopover by the Beagle at the volcanic islands of Cape Verde quickly convinced Darwin that Lyell’s analysis was correct.
Later, in Brazil and Argentina, Darwin noted fossils of extinct mammals that resembled modern species. They led him to the idea of a kinship between these animals and to the idea of transformation, an evolution over the course of time.
There was also the stop in the Galapagos Islands. Darwin observed that from one island to the next, the form and the size of the beaks of finches were different, at the same time that the food available on each island was also different. Later, after his return to England, his specimens were studied by an eminent ornithologist, a bird specialist. Darwin came to understand that the finches were different species and that these species had been transformed. These finches, he explained, all came from a root species. On each island they underwent modifications, including in the shape of their beak; thus the form best adapted to the available food resources was selected. In this way, a new species was formed.
In 1842, six years after his return, Darwin composed the first manuscript of On the Origin of Species by Means of Natural Selection, asserting his idea of a slow evolution of living beings over time and explaining the mechanism of this evolution: the appearance of new characteristics (no one knew anything then about genetics or mutations) and the natural selection of those characteristics that offered, to the individuals who carried them, an advantage for survival and reproduction. He also asserted the unity of the living world, the links of descent between extinct species and living species and the links that all species have with each other in a great evolutionary tree with roots in the first forms of life.
While Darwin composed his first manuscript in 1842, he didn’t decide to publish his book until 17 years later and then only because another naturalist, Alfred Russel Wallace, was reaching the same conclusions. Wallace’s work threatened to take the credit for his ideas away from Darwin.
Darwin dreaded the scandal his book was sure to produce among religious people and he was not wrong! Even though in his 1859 book Darwin didn’t say a word about the origin of humanity – he waited until 1871 to do this – his whole reasoning implied that the human species doesn’t escape this line of descent, this kinship with all other living beings. The reasoning also implied that the origin of humanity had nothing to do with a great divine organizer. As for Darwin – he explained in his autobiography that he had escaped the dogmas of the Bible and given up his faith.
Today, 150 years later, the evolution of the earth, of life, and of the different species is accepted by everyone, at least by everyone who has access to culture and knowledge. Certainly, and even in countries with the most advanced knowledge, there are still reactionaries who challenge evolution and defend “creationism” or some other divine “design.”
But evolution is an indisputable fact, proved many times over by the discoveries of genetics and documented by a much larger array of fossils, as well as a much wider examination of the millions of species that inhabit or have inhabited this earth.
Much of what science has learned of DNA, for example, or of the mutation of viruses, is solidly based in Darwin’s revolutionary theory of evolution. Modern biological research is grounded in Darwin.