(ORDO NEWS) — Perhaps the most famous postulates of the scientific theory of Charles Darwin are the origin of humans and monkeys from a common ancestor and the principle of “survival of the fittest.”
But how could a British scientist formulate them in the 19th century, when the mechanisms of inheritance and genetics were not yet known to science?
Not all scientific hypotheses put forward by scientists of the 19th century were confirmed. In this regard, the theory of evolution of Charles Darwin is a rare case when modern scientists have proven the veracity of his judgments.
All his thoughts and theories regarding how organisms evolve from generation to generation, Charles Darwin first formulated in his work “The Origin of Species by Means of Natural Selection” (1859).
In this work, the scientist argued that in a population there may be various signs, from which, in the course of evolution, the most successful ones are selected, so to speak.
That is, individuals that, due to their characteristics, are better adapted to the environment, will be able to have more offspring, which means that their cubs are more likely to inherit more “winning” traits.
Over time, the traits that allow species to survive and reproduce will become more frequent, and the population will change or evolve.
From this it was logical to assume that due to such natural selection, genetically diverse species could in theory have one common ancestor. For example, such “distant relatives” can be humans and monkeys.
By the way, Darwin also described a form of natural selection that depends on the success of an organism in attracting a partner – we are talking about sexual selection. So the colorful plumage of peacocks and the antlers of male deer are examples of traits that have evolved under this type of selection.
Charles Darwin used the term “natural selection” as opposed to artificial selection – that is, selection, in which people independently choose the most successful trait.
But how did Charles Darwin come to such curious conclusions?
How did Darwin’s theory of evolution come about?
Charles Darwin lived and worked in the 19th century, when neither the mechanism of trait transmission nor genetics was known. He also didn’t know about genetic mutations, which are the source of natural variation.
The scientist himself mentioned many times that for the first time his hypothesis was formed in 1842, when the book of the great English economist Thomas Robert Malthus, An Essay on the Law of Population (1798), fell into his hands.
In his work, Malthus noted that the population of the Earth is increasing exponentially over time, but the resources necessary for existence are arithmetic – that is, several times slower.
This phenomenon impressed Darwin so much that he projected this principle to all wildlife, suggesting that in natural conditions some species also lack food sources and habitats. Four years after becoming acquainted with the work of Robert Malthus, Charles Darwin created the first outlines of his future evolutionary theory.
How species evolve
According to the American Museum of Natural History, natural selection can slightly change the appearance of members of a population, such as changing skin or plumage color, as well as size. When such transformations occur over a relatively short period of time in a small group of organisms, scientists call it “microevolution.”
But when completely new species are formed for a long time, it is believed that “macroevolution” has occurred. For example, macroevolution turned dinosaurs into birds, amphibious mammals into whales, and the common ancestor of apes and humans into humans, chimpanzees, and gorillas.
Archeopteryx is the first bird-like dinosaur that lived approximately 150 million years ago during the Jurassic period.
Evolution of whales
The most curious phenomenon that Darwin described is the evolution of whales. In the first edition of The Origin of Species by Means of Natural Selection, the scientist speculated about how natural selection might cause a land mammal to evolve into a whale.
As a hypothetical example, Darwin used the North American black bears, Ursus americanus, which are known to catch insects by swimming in the water with their mouths open.
“I see no difficulty in the fact that the population of bears, as a result of natural selection, would turn into a more aquatic species in its structure and habits – their mouths would grow larger and larger until a creature as monstrous as a whale would appear. , he thought.
Semi-aquatic four-legged ancestor of the whale Phiomicetus anubis, who lived about 43 million years ago in the territory of modern Egypt
The idea was not well received by the public or other scientists, and Darwin received a lot of ridicule because of it. As a result of the negative reviews, the researcher was so embarrassed that he removed the bear part from later editions of the book.
But modern scientists know that Darwin had the right idea, but he chose the wrong animal. Instead of starting from bears, he had to investigate cows and hippos. In the early 1990s, paleontologists discovered evidence that whales evolved from land mammals.
In the course of evolution, their nostrils have moved higher so that it is convenient to inhale air without rising too high above the surface of the water. Other parts of the body of early whales also changed – the front legs became fins, the hind legs disappeared altogether, their bodies became more streamlined.
Over 60 million years of evolution, grandiose species changes have occurred: Indohyus, Ambulocetus, Rodhocetus, Basilosaurus, Dorudon and, finally, the modern humpback whale
Thus, at a minimum, there is no doubt in the theory of the evolution of whales – they really did originate from land mammals, as Charles Darwin predicted.
However, many people still continue to doubt the veracity of evolutionary theory, despite all the evidence that geneticists, paleontologists and other scientists can provide.
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