The origin of man refers to the beginning of everything, to the appearance of the first rational hominids on planet Earth. The different theories about the appearance of man have evolved over the years, four of which are the best known and most important that are currently accepted. Today we review the four theories about the origin of man most accepted today :
Theory of Evolution
The most accepted and known in the world. Scientists place this Theory of Evolution as the most accurate perspective to explain the origin of man . It was Charles Darwin who managed to demonstrate and gather enough information to point out that species evolve and change over the years.
These ideas are based on several concepts that Darwin defined in his Theory of Evolution:
- Species of living things evolve over time
- The population of each species descends from a common ancestor between them
- The world changes, it is not static
- Related species descend from common ancestors
- Species are composed of individuals that are not usually identical to each other
This Darwinian theory of the origin of man occurs by the mechanism of the appearance of heritable variations , which amounts to the survival of those who best adapt to the environment. These beings leave more offspring and over time alter the species until they constitute a new one.
Evolutionary changes occur in an adaptive way , so that the species adapts depending on the selective pressure it undergoes. To take a simple example, the cold of the Arctic will put pressure on all species to be more resistant to low temperatures, and those that do not will die.
Charles Darwin was convinced that changes in species were due to the environment and, furthermore, these were inherited from father to son. He believed that evolution had a purpose: to make organisms more perfect .
Since the 1950s, the theory of evolution combines the proposals of Wallace and Darwin with Mandel’s laws, hence the name of modern synthesis. According to this theory, evolution is a change in the frequency of alleles in a given population over time.
Lamarck theory
It was exhibited by the French Jean-Baptiste Lamarck. Lamarck also follows an evolutionary doctrine, but, as a naturalist, it was a more special vision. In his ‘Zoological Philosophical Work’ he explains the sequence of events that give rise to the origin of man:
- Changes in climate create new needs for species
- These changes determine the use or non-use of both organs
- These organs develop or atrophy
- Acquired characters are hereditary
The term ‘Lamarckism’ is used to refer to this theory of the origin of man. The French naturalist proposed in the early 19th century that all life forms had evolved through generations from simpler life forms.
Mendel’s Laws
Mendel’s Laws speak more about the genetic inheritance of the species than about their own origin. The combination of genes determines the dominant or recessive character depending on the species, as explained in his theory by Gregor Mendel.
At the time of the presentation of his results in 1865 , they were ignored. It took more than 30 years for their contributions to the origin of species to be recognized.
Mendel’s three laws are as follows:
- Principle of uniformity: when two purebred individuals are crossed, the first filial generation will be exactly the same between them.
- Principle of segregation: the crossing of two individuals of the first filial generation will produce a second filial generation, in which the genotype and phenotype of the recessive individual will reappear.
- Principle of independent transmission: determines that there are some traits that can be inherited independently, as long as the genes that are on different chromosomes and that do not intervene between them.
It should be noted that this theory was only taken into account from the 20th century, and today Mendel’s laws are the basis of the different theories that exist in the field of genetics .
Creationism
Possibly the other most followed great theory in the world. Far from being based on science, the Creation Theory is fundamentally based on faith.
Man was created by the gods who gave rise to religions. For Christianity, man was created by God with clay and made woman from her rib. From here, everything evolved.
