Confirmation of the theory of evolution, or Atavism, rudiments, homologous and analogous organs

In science, the concept of the unity of the origin of life on Earth is considered fundamental . And so the discovery, which is applicable to one of its forms, can be attributed to all the others. Thanks to this, by the way, the functions of many internal organs of a person were studied and ways of treating dangerous diseases were developed.

Examples of similar and homologous organs

It is impossible, however, to rely on the similarity of all life on earth, to mix homologous and similar organs. The first have the same structure and develop from the same embryo embryos, confirming the unity of origin (for example, five-toed limbs of different animal species). But similar organs, often performing the same function in different animals, have different rudiments.

A common example of such cases is the wing. It has an identical function in both insects and birds. But insects are chitinous protrusions on the surface of the back, and in birds - the forelimbs, modified in the process of evolution. The same parallel can be drawn between the gills of the dragonfly larva and the fish.

The eyes of a person and an octopus can also be defined as similar organs. Despite the external similarity, they are absolutely
Are different in structure. The lens of the human eye is fixed, and the eye itself is an outgrowth from the rudiment of the brain. While in the octopus, the organs of vision are the formation from the veil of the body, in which the lens of the lens approaches or moves away from the retina, aiming at the object of attention of the animal in order to establish the correct focus.

Examples of analogy can be considered even among pigments, such as hemoglobin and hemocyanin. They equally carry oxygen, but their molecular structure is very different.

Rudiments

In their own way they confirm the theory of the origin of life of atavisms and rudiments.

The latter include, as a rule, those bodies that do not fulfill their original function, having lost it in the process of evolution. But all rudiments can not be considered completely useless. They just often perform less important actions.

For example, the ostrich's wings can be defined as vestigial organs, because they do not cope with the main purpose of the bird's wing, but are used by them to attract females and to maintain balance during running. Thus, the complexity of the structure of this body is inadequate to the simplicity of the task that it performs. This is a sign of rudiment.

But the wing of the penguin can not be considered as such, since it performs a rather complex function as a fin.

The rudiments include the eyes of a mole and a mole rat who either do not see anything at all, or only distinguish darkness and light.

In humans, this characteristic has caudal vertebrae, muscles, which Helped our ancestors to raise their hair on end, and the muscles to move their ears. Everyone knows another human rudiment - the process of the cecum (appendix).

Atavisms

When an individual develops features characteristic of its distant ancestors, this phenomenon is called atavism. For example, the appearance in some people of a continuous hair cover on the body or an additional pair of mammary glands, a tail-shaped process in humans or the dorsal fins of a dolphin.

The appearance of atavisms can be explained by the presence of genes responsible for this feature in DNA. But they have not functioned for a long time, since their action is suppressed by other genes.

Homologous and analogous organs, rudiments and atavisms - all this is an undeniable confirmation of the unity of the origin of the life of beings inhabiting the Earth.