the various Theories about the origin of man They have managed to provide an answer to what may have been and is one of the greatest unknowns that human beings have faced. The diversity of races and the origin of man continues to be a subject of study, modifying, improving and in other cases discarding the different theories that have emerged throughout our own history.
We will agree that the different archaeological and scientific advances have modified or, in the best of cases, improved the different theories that have been proposed throughout the history of the human being, about its origin and diversity.
To explain the different theories we must review history, beginning with the oldest theory and today totally discarded by the scientific community as it is the Creationist Theory.
Theories that explain the origin of man
To better understand evolutionary theories we must know some concepts:
What is Evolution?
Evolution is the ability of living beings, in this case man, to adapt to constant changes, whether geological, climatological, etc. It is for this reason that we can observe in nature the great variety of living beings, each and every one of them responds to a principle of survival, it is for this reason that many species have disappeared and others have adapted to new circumstances and they have even given rise to new species, the vast majority of which respond to changes produced on our planet, on its surface.
Evolution is the adaptive result for a long period of time at new conditionsWithout adaptation, the result can be extinction, which is why many species of living beings have disappeared from our planet.
Other species have been able to modify their genetic composition, a modification that will be inherited by the following generations and therefore giving rise to evolution.
We can say that human evolution is the capacity of genetically modify the biological composition over a long period of time and gradually to give rise to a new group of beings adapted to the new conditions.
These transformations can become so important that in many cases, the final individuals bear little or no resemblance to their ancestors. Within the evolution we can say that there are two types: Small evolutions or microevolution and great evolutions or macroevolution.
the little evolutions they occur within the same species, forms of adaptation of nuclei that, starting from the same base, evolve in different ways depending on their habitat or environmental conditions. Microevolutions can give rise to new species better adapted to the environment.
A example of microevolution It can be like starting from a breed of dog, different breeds can be given, individuals capable of reproducing among themselves, giving rise to another different individual. We have another example in the image above where we can see changes in the pigmentation of ladybugs.
Microevolution, therefore, is totally transferable to the evolution of man, there are different races thanks to the adaptability of the human being to his environment, overcoming different challenges such as food, weather, etc.
the great evolutions or macroevolution responds to large-scale changes, significant changes, where from one population a completely different one is generated and even extinction itself. To talk about macroevolution we have to take fossil remains as a reference, it is an evolution that goes beyond species.
What example of macroevolution we can put ourselves, how human evolution has taken us from Australopithecus to today’s Man, leaving hominids along the evolutionary path that did not evolve and became extinct.
Creationist Theory
This theory starts from ideological current of creationismwhere all species, including man, had been created to occupy a different space, where each living being occupies a specific and invariable place and therefore no possibility of evolution.
This theory is based on theory of a creator and therefore there would be no possibility of kinship between the different living beings. This theory was prevailing until the beginning of the 19th century, although it coexisted for some time with the evolutionary theory, it will soon be discarded by the scientific community with the appearance and study of the various fossil remains.
Evolutionary Theories
- Lamarckism or Transformism
Although the origin of man has been a subject of study since Classical Greece, it was not until the beginning of the 19th century that the First Theory of Evolution formulated by Lamarck. Science-based theory where, based on 4 principles, it explains how evolution responds to a need for survival, making them increasingly complex beings.
These principles are:
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- Life impulse or vital. Improvement of organisms, this improvement arises from an inner force for survival.
- Alterations in your environment. The alterations caused by the different changes in their habitat cause these modifications.
- morphological alterations. Due to the alteration of their environment, the organisms tend to use and therefore to develop parts of their organs, which causes morphological alterations, propitiating a greater development of these and causing the atrophy or disappearance of the disused organs.
- The morphological alterations are inherited in the following generations.
With these principles Lamarck explains the reason for the different forms of life, starting from a common point and according to the needs of its environment, as long as these needs are prolonged over time, the organism will be able to transform the organism to adapt it to the environment. environment and this modification will be transmitted to future generations of individuals.
Darwin focused on the diversity of the different species collected in his work The origin of species through natural selection. Darwin was the first scientist to write a book on the evolution of man, late nineteenth century, under the title of The origin of man and selection in relation to sex. It is about bringing the theory of evolution raised in the origin of species to human evolution based on sexual selection.
Darwin explains the evolution of species through 3 formulations:
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- Excess of population. All populations, regardless of their species, procreate many more individuals than can survive by nature. The survival instinct is postulated, the strongest of each population will survive in a natural environment of scarce or limited resources. This is how natural selection is achieved.
- fittest individuals. Within the same species, Darwin appreciated small characteristics or variations compared to others. These variations will provide individuals who are better trained and better adapted to the environment in which they live.
- Natural selection. The best adapted individuals will have more possibility of transmitting these characteristics to their descendants, this will be achieved with the passing of the different generations, individuals increasingly adapted to the point of generating new species thanks to the successive accumulation of these characteristics
Expands knowledge about Biography and Darwinist Theories.
Already situated in the 20th century and thanks to the Scientific advancesit was possible to reformulate some of the theories exposed in previous centuries, fundamentally in the theories about the evolution of man formulated by Darwin on genetic variability and natural selection itself. To Synthetic Theory It is also known as Neo-Darwinism.
These formulations are based on the various paleotological studies as well as the study on Molecular Geneticdisciplines that shed light on the previous postulates giving a scientific explanation to the Darwinian theories, being their main contributions:
- Thanks to natural selection, genes with a adaptation value low are eliminated, enhancing the genotypes with greater adaptive power.
- Mutation and genetic combination occurs during reproduction, the combination of the different genotypes will result in new genotypes in future generations.