Although it is hard for us to imagine it, the animals and organisms that inhabit the planet Earth, have not always maintained the same aspect and characteristics that we know today, but, they have evolved from other species and developing small modifications that have allowed them to adapt to their environment and survive. In this way, there are many other species that have been extinguished because, they have not managed to evolve or adapt to their environment.
Do you want to know more about this process? In ecology, we tell you What is natural selection with examples.
What is natural selection: definition and example
The term natural selection refers to selection that occurs in the nature of those characters or genetic features that are more appropriate and that favor the survival of the species, so that, these are transmitted to their offspring in order to ensure the preservation of the species.
A Example of natural selection It is the transmission of the gene that defines the length of the giraffes neck. Imagine for a moment that the giraffe comes from a predecessor very different from this species, with the neck much shorter, similar to a horse. This species fed on the leaves of the branches of the trees, so that, it had to continuously stretch its neck to obtain food, so that the species with the longest neck would have more possibilities of obtaining food than those that had a shorter neck.
Therefore, with the passage of time, the species with the shortest neck, they had less options to meet their nutritional needs and survive, while, those with the longest neck continued, feeding and reproducing, transmitting, therefore, this genetic characteristic to its offspring, which each time, would present a longer neck. This happens with all kinds of genetic characters in all species of living beings, giving rise to what we know as Biological inheritance of each species.
Types of natural selection
Within this we can find different types. Specifically, the different types of natural selection are:
Disruptive selection
This type of natural selection usually gives rise to two different species. So, there is no extinction of any of the species but, both are able to subsist and adapt to the environment. In the previous example for example, it would imply the survival of both the species with the short neck, and those with the long neck.
Directional selection
This other type of selection implies that, over time all individuals adopt a new character, while those who are not able to evolve are extinguished. This type of selection corresponds to the example explained above.
Sexual selection
This natural selection takes place in the populations of individuals who compete to be able to reproduce, so that, over time, individuals inherit and adopt the characteristics that allow the subsistence of the species.
Lamarck and Darwin’s theories
One of the first researchers who rang on this theory was Lamarckwho defended that the development of species are capable of modifying their body physically from the changes produced in the environment, and these changes are transmitted to their offspring. However, this theory has not been approved by the scientific community, since, individuals have a series of limitations when modifying their body and it is not their actions that give rise to these modifications.
Charles Darwindefended that these modifications are not due to their training or use but also links them to the demands of the environment, so that the modification of certain characters and its transmission takes place through a slow process that favors that certain features are transmitted to the offspring. Darwin published his theory in his book, about the Origin of species through natural selectionwhich caused a great impact and controversy in its time. However, the passage of time has not only been accepted by the scientific community but, it has also been supported today constitutes the basis of modern evolutionary theories.
Natural selection and artificial selection
The human being has once understood the process of Natural selectionhe has been able to imitate and force him, thus giving rise to the Artificial selection.
In this type of selection is The human being who selects the characteristics which considers beneficial and adequate for the species and encourages its offspring, forcing the crosses between individuals, either through the traditional reproduction method or the in vitro reproduction method, produced in the laboratory.
Currently, this type of selection is applied to achieve the desired characteristics in domestic animals and plants or food products, such as transgenic foods.
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