Charles Darwin and the theory of Evolutionism

History

Introduction

In this article we will find out how various scientists from different eras have hypothesized the theory of the evolution of living species.

Ancient Greece

Our journey begins in Greece, more than 2000 years ago. Many thinkers and philosophers of the time hypothesized that all living species come from a common ancestor, thus laying the foundations for the search for truth. However, Aristotle creates the concept of fixism, that is, believing in the theory of evolution given by the bible.

Aristotle and his master Platon

The Church and the Medieval Age

With the advent of Christianity, the Church prevented any research that could lead to the discovery of the reality of the facts, this because it would certainly have questioned the belief of its faithful in the doctrine professed by it. Research began in the mid-1700s, thanks to the trust that people were giving to the discovery of science and progress, thus pushing some naturalists and scholars to challenge the Holy See, formulating ideas about the age of the Earth and the relationships between organisms.

Lamarck and the first idea

In 1809, the biologist Jean-Baptiste de Lamarck published in his Philosophie zoologique the first coherent model of evolution, according to which the transmission to subsequent generations of traits acquired through the use and disuse of body parts was envisaged. This theory, however, was not exact and in fact, his theory will be disproved. The main reasons why this idea of ​​evolution is wrong are 3:

Charles Darwin and his Trip

In 1859, the biologist Charles Darwin published his book in London called "The Origin of Species by Natural Selection"; in this work the thought of Lamarck will be taken up, even if Darwin did not know it, also correcting the errors made by this, thus defining the theory of evolution. But how did this come about? When he was 20, Darwin came into contact with a book by the geologist Charles Lyell (principles of Geology), which provided clues to a much more remote geological past than was thought at the time. The biologist was very impressed by this text because it was able to give strength to the theories that he had already hypothesized at a ripe old age. Around the same time, the scientist was sailing around the world to seek help and evidence for his research. According to Lyell's theories, the great geological transformations were the result of small and gradual changes still taking place, calling this principle actualism in the future. At the time there were no planes, so Darwin had to travel his 5-year journey on the brig Beagle, visiting various parts of the world. In this period he took a lot of tests to be able to verify his theories, such as fossils, insects, finches of different populations, turtle shells, animals and much more, thus maturing in him the belief that they all descended from a common ancestor. His main goal was to find champions who could help him in his research, not being disappointed. Important were the Galapagos Islands, where Darwin was able to find various different populations, such as the finches and the giant turtles. In the future he will describe this journey in his autobiography, defining it as the most important moment of his life and for humanity.

The Theory of Darwin

"The origin of the species" and the critics

Aristotle and his master Platon

As we arleady said, Charles Darwin published his book "The origin of the species" in 1859, in the work he proposed a revolutionary explanation, for the time, of a phenomenon that had always attracted the attention of scholars, such as the enormous variety of forms of living organisms. The criticism of the Church was extremely harsh. It found the inevitable implications of evolutionary theory blasphemous; he also saw a threat to his authority:

man was no longer at the apex of divine creation, but the result of a long process of natural selection, like all other organisms. Reconciling an immortal soul with an "ape-like" body was no small feat, and the opponents were not only among the prelates. Many Catholic and conservative intellectuals and even some naturalists rejected and ridiculed the theses of Charles Darwin, not understanding their real significance.

The Theory of Evolution made by Darwin

According to Charles Darwin's theory, all living species are related to each other and descended, through successive modifications, from common ancestors who lived in more or less remote times. Going back in time we would arrive at the common ancestor of all species. He articulates his reasoning starting from two observations:

  1. Often the members of a population have variable characters, most of which are inherited from the parents;
  2. All species can generate more numerous offspring than that which can then find sustenance in the environment. The disparity between the number of individuals and available resources necessarily leads to a "struggle for existence". In this struggle for existence, the fittest survive, that is, the individuals whose characters are most advantageous. All the others do not survive, because nature (scarce food, adverse climate, predators, etc.) operates a natural selection.

The surviving individuals, therefore the most suitable ones, by reproducing, transmit to their descendants the advantageous characteristics, defined adaptations. All species can generate more numerous offspring than that which can then find sustenance in the environment. The disparity between the number of individuals and available resources necessarily leads to a "struggle for existence". In this struggle for existence, the fittest survive, that is, the individuals whose characters are most advantageous. All the others do not survive, because nature (scarce food, adverse climate, predators, etc.) operates a natural selection.