From Antiquity to evolutionary biology intrigues researchers and the general population. The term evolution has Latin origin and derives from the word “evolution”, which means to unfold. Evolution is therefore about change.
In antiquity, an idea was widespread about the origin of species: the fixism. According to this line of reasoning, all living beings that exist today already existed in the past and would have been created by God. Thus, according to this thought, the species did not undergo changes over time and, consequently, there was no evolution.
With advances in studies of fossils and sedimentary rocks, it has become increasingly clear that today's species do not were the same ones that existed millions of years ago, as well as that many different beings existed in the past and they died out. Thus, in the eighteenth century, the spread by various naturalists, including Buffon, of the idea that beings underwent changes over time began. However, none of these researchers tried to explain this evolutionary mechanism.
The first evolutionary theory presented was that of Jean-Baptiste Lamarck (1744-1829). At your job Philosophy and Zoologique (1806), Lamarck tried to explain, in the sense of complexity, how species evolved. This scholar made use of two basic principles: a law of use and disuse and the law of inheritance of acquired characters.
According to Lamarck's law of use and disuse, the species showed changes in their bodies as a consequence of the frequent use of a certain organ or the lack of use of a structure. By using an organ a lot, for example, it would become stronger and more developed. On the other hand, the little used organs were heading towards atrophy. Also according to the theory proposed by Lamarck, all the characteristics acquired during the life of a living being were transmitted to their descendants.
To explain his idea, Lamarck used a well-known example: the giraffe's neck. According to this scientist, there were short-necked giraffes initially, but in order to reach food at great heights, they began to stretch. By intentionally forcing the neck to stretch, this structure began to appear larger and larger. This characteristic was then passed on to the descendants.
Lamarck, however, was mistaken in certain points of his theory, since use and disuse do not provoke modifications that can be passed on to offspring and the modifications acquired during life cannot be transmitted. Despite the mistakes, Lamarck raised a very important point for evolution: the environment influences the evolution of species.
After Lamarck, was the theory proposed byCharles Darwin(1809-1882) who tried to explain how evolution actually happened. According to Darwin, evolution did not happen towards complexity, but because of a struggle. constant for survival, as only the fittest survived and passed on their characteristics to the descendants. Darwin named this process thenatural selectionand considered it the main mechanism of evolution.
Another important point of Darwin's theory is common ancestry, which states that all organisms share a common ancestor, being, therefore, products of a history of descent.
As Darwin did not have the basis of genetics and did not know how traits were passed on to descendants, his theory failed to explain certain important points of heredity. However, from 1940, Ronald Fisher, John Haldane, Sewall Wrigth, Theodosius Dobzhansky, Ernst Mayr, Julian Huxley, George Simpson, and G. Ledyard Stebbins published works in which Darwin's theory was reinterpreted through the most modern knowledge of Genetics and other areas of Biology. This reinterpretation became known as synthetic theory of evolution or neo-Darwinian theory.
According to the synthetic theory of evolution, evolution occurs through some major factors, such as mutation, gene recombination, genetic drift, migration and natural selection.
Although a great deal of knowledge has already been incorporated into Evolutionary Biology, much remains to be explored and studied. In this section you will learn about all existing evolutionary theories, as well as stay informed about what is new in this field.
Good studies!
“Nothing in biology makes sense except in the light of evolution"
Theodosius Dobzhansky
By Ma. Vanessa dos Santos
Source: Brazil School - https://brasilescola.uol.com.br/biologia/biologia-evolutiva.htm