- Somaya Nasr
- BBC News Arabic
Although more than 160 years have passed since the publication of the book “On the Origin of Species” by the British scientist Charles Darwin, it is still considered one of the most important scientific books, and even the most important at all, according to some surveys conducted in recent years, as many see that it changed the way Scientists and ordinary people think about many things related to life on planet Earth.
The genius of Charles Darwin, and the way he turned biology upside down when his book On the Origin of Species was published on November 24, 1859, sometimes gives the false impression that the theory of evolution has been completely missed by the famous scientist. Preliminaries or precedents. But scientific history proves that the raw scientific materials on which Darwin built his theory were known decades earlier.
Geologists and archaeologists had already provided strong evidence that life appeared on the planet a long time ago, that it changed over time, and that many types of living creatures were subjected to extinction. Naturalists, natural historians, and embryologists also discovered, perhaps without realizing it, many things that Darwin used as evidence to prove his theory.
Some precursors of the theory of evolution in the modern era
The “Lamarckian” theory: French scientist Jean-Baptiste Chevalier de Lamarck (1744-1829) was the first naturalist to write at length that the long-term “inheritance of acquired characteristics” could lead to a change in species. His evolutionary theory is based on the principle that physical change that occurs in organisms – such as the development of an organ or limb, for example, through increased use of it, can be transmitted to offspring.
For example, Lamarck believed that the giraffe’s neck increased in length by each generation extending its neck up to reach the leaves of high trees, which caused a change in the shape of the body inherited from generations. But critics of the “Lamarckian” theory soon pointed out that if this assumption was correct, the sons of weightlifters would be born with huge muscles, or the sons of cowboys were born with bowed legs, as happens to their parents after spending most of their lives riding horses. But despite the error of the theory, the ideas of scientists were directed to the issue of evolution.
The theory of “uniformitarianism”: The Scottish geologist James Hutton (1726-1797), and after him the British geologist Charles Lyle (1797-1875), developed a theory of unification of origins and principles that is based on the features of the Earth, such as mountains and oceans. , formed over a long period of time through a gradual process, and that natural phenomena, such as volcanoes and earthquakes, are still changing the surface of the planet at the present time in the same way that they have changed it over time.
Darwin made use of this theory to support his idea of how species arose. If there was enough time for mountains to form and take hold or crumble and fade, then surely there would have been enough time for millions of living species to appear, evolve or go extinct.
Lamarck believed that life struggled over time to transform from single-celled organisms to more complex organisms. Many German biologists at the time believed that life developed according to predetermined rules, in the same way that a fetus develops in the mother’s womb. But in the mid-19th century, British naturalists and biologists Charles Darwin (1809-1882) and Alfred Russell Wallace (1823-1913) independently came up with a natural way of how life changes that we can observe – a process that Darwin called “natural selection.” . They both note that if an animal has certain traits or characteristics that help it adapt to its environment, or reproduce more successfully, these traits become more common in subsequent generations. Individuals with characteristics that enable them to adapt are more likely to survive, reproduce, and pass on genes.
One of the most influential books in history
Darwin’s book On the Origin of Species by Natural Selection was not only a bestseller upon its publication in 1895, but became one of the most influential scientific books in human history ever. The book includes a scientific theory that organisms evolve over generations through natural selection, and presents evidence indicating that the diversity of life forms stems from common ancestry that evolved over time.
Darwin benefited greatly from his trip around the world on board the ship “HMS Beagle”, as Darwin spent about five years roaming the continent of South America and its islands, especially the archipelago of the Galapagos Islands, where he observed and studied many types of animals and birds, and collected Thousands of samples he sent to Britain for detailed study.
The book was intended for the ordinary reader, not the specialist, and it received wide attention upon its publication. Darwin was then a well-known scientist, so his findings were taken seriously, and resulted in scientific, philosophical and religious debates. But it took a long time to accept Darwin’s theories. Within twenty years of the book’s publication, the majority of scientists in Europe had come to support the idea of evolution and the idea of species descending from common ancestors.
However, the idea of natural selection has found it more difficult to spread. In the late nineteenth century, many scholars who considered themselves “Darwinists” favored Lamarack’s explanation of the way life has changed over time.
But with the discovery of genes and genetic mutations in the twentieth century, the explanation of evolution through natural selection became something that could not be ignored.
Examples of Evolution
Viruses and bacteria, says Prof. Rana Dajani, who specializes in molecular cellular biology at the Hashemite University in Jordan, are a clear example of evolution. “The influenza virus, for example, mutates and evolves all the time, so we have to get a new vaccine against it every year. The same goes for the Covid-19 virus: different types appear all the time, and the vaccine may be effective against some of them, but Not all of them. Evolution happens all the time, and we see it nowadays, and it’s most evident in simple organisms, but it takes a very long time before its effects are evident in complex organisms.”
Recently, a study published in the journal “Science” concluded that African elephants are going through a stage of genetic evolution, where some are born without tusks, after suffering from decades of illegal poaching to use their tusks in the internationally banned ivory trade.
This genetic condition is becoming more common in elephants from Gorongosa National Park in Mozambique. About 90 percent of the country’s elephants were slaughtered between 1977 and 1992 by armed groups carrying Kalashnikovs to use their tusks in the ivory trade, thus financing the bloody conflict in the country.
Most of the elephants that survived from poachers had one important trait in common: half of the females were born without tusks, whereas before the war, the percentage was only 20 percent, what researchers considered a spotlight amid a torrent of worrying news about the endangerment of these animals.
At the time of the book’s writing, the dominant explanation for the origin of life in Europe was what is known as the creation theory, which refers to the existence of a god who created the universe and all life on Earth.
Creationists did not accept Darwin’s theories, which they saw as a competing way of explaining the origin of species – through descent from common ancestors. Darwin was aware that these would find it difficult to accept his theories, but in his book he tried to refute the “creation theory” and prove that it is inconsistent with the evidence.
Darwin himself was not apparently opposed to the idea of a creator god, writing in the conclusion of his book “On the Origin of Species”: “…probably all living things that have ever lived on this earth descended from a single primitive form after life was breathed into it by the Creator. “. Some have interpreted this as that Darwin believed that it was the divine ability that created life, and then this life became subject to mutations, variations and natural selection. Perhaps this was a conciliatory move by the British scientist, aimed at reconciling religious and scientific interpretations of life.
This may explain Darwin’s avoidance of talking about the evolution of the human race, and some references indicate that he initially intended to include a chapter in his book dealing with human evolution, but later changed it (although he devoted a separate book to that later). Perhaps he thought that his book had enough – and more – to provoke controversy. His intuition was correct, as opinions were divided about the book, between those who considered it the foundation of modern biology, and those who described it as a serious threat to the essence of humanity.
Darwin did not claim that “natural selection” had the power to create new varieties of organisms, but only that it could influence those already in nature.
The location of the “Origin of Species” on the scientific map now
Over time, many wonder whether Darwin’s famous book, with its theories, still occupies a prominent scientific position despite the successive scientific and technological developments we are witnessing.
Professor Rana Dajani says that the theory that Darwin put forward about evolution more than 160 years ago “remains the best explanation for the idea of the emergence of different types of living things on the globe. Of course, the theory has evolved and been added to, and became more complex, but its basis has not changed, as it remains the The best interpretation of the idea is within what information and tools we have at the moment.”
Of course there were some things that Darwin did not understand, or did not understand well. But despite the passage of more than 160 years since the publication of On the Origin of Species, and despite the amazing progress that scientists have made, especially in areas such as genetics and the study of fossil records, many researchers in the branches of biology say that it is surprising that a large number of evidence that They are discovered in those areas that do not contradict Darwin’s ideas, but often support them.