Theories of the evolution of man – Universal History

The transformation of beings, such as man, is explained by resorting to evolutionary theories, whose authors are Juan Bautista Lamarck and Charles Darwin. These theories try to explain the evolution of man.

Lamarck (1744-1829)

It’s a French scientistproposed three ideas for the evolution of man:

• The environment modifies the structure of plants and animalsjust as a tree on which a constant wind blows in only one direction leans in that direction and an animal living at the North Pole acquires warm fur
• Frequent use of an organ strengthens it and favors its growth, in a similar way to the disuse of an organ weakens it and leads it to its disappearance. For example, the blacksmith has strong arms, the ballerina has strong leg muscles.
• Acquired traits are passed on to offspring. We have the case of giraffes that had to grow their necks in order to reach the foliage of the highest parts of the trees, therefore their descendants inherited their characteristics.

Charles Darwin (1809-1882)

Was a english naturalist who went around the world studying plants and animals and then classifying them. As a result of that great trip he contracted a tropical disease that forced him to lead an invalid life. Nevertheless he managed to publish twenty scientific books. One of them was The origin of species published in 1859 where he proposed the Theory of Evolution.
The fundamental characteristics of the theory of evolution are two: natural selection and the variability of the species.

natural selection

It consists in that only the strongest, fittest, most adapted individuals survive, the rest die or are eliminated because they are not needed.
This idea arose from reading the English economist Tomas Malthus, who argued that the number of births is so great that, if all descendants survive, a thick crust of life would soon form on the earth’s surface; an oyster produces millions of young and yet the sea does not become a compact mass of molluscs.

The variability of the Species

It is the determined number of similar but not identical individuals that make up a species. The more favorable variations individuals have, the more options they will have to survive and produce a greater number of offspring.