What is the biological significance of natural selection? Examples in animals and plants

Natural selection is one of the basic processes of the evolution of living organisms. What is the biological significance of natural selection? What mechanisms for its implementation is owned by nature?

The emergence of a theory

The idea that the present image of organisms is the result of long evolutionary processes, began to mature in the XIX century. This issue at that time involved several scientists. Already in 1855, Alfred Russell Wallace published his article, which he devoted to thinking about evolution through natural selection.

The idea of Wallace was immediately picked up by Thomas Malthus, writing a paper on "The experience of the law of settlement." He suggested that the goal of each population is reproduction, and when the number of individuals becomes too large, some of them die. Here, incidentally, came the thought of Wallace that not casual organisms die, but the weakest.

The theory of natural selection was reflected in the work of Charles Darwin "The Origin of Species" (1859). The scientist came to his conclusions after a round-the-world expedition on the Beagle ship of 1831-1836. And although his work was published later by Wallace's article, it was Darwin who became the main conductor of this hypothesis, challenging supporters of the divine origin of all living things.

What is the biological significance of natural selection?

Evolutionary theory has long been rejected, even now many consider it an invention. However, the existence of natural selection is difficult to refute. Its main principle can be formulated as follows: "the strongest survive".

The natural selection of Charles Darwin is that nature constantly filters out weak individuals. A similar situation is observed in artificial selection, when the gardener chooses the most suitable and viable shoots for planting in the ground. Wildlife does the same.

So, what is the biological significance of natural selection? First of all, in the qualitative improvement of the population. In conditions of habitat changes, if the number of populations increases sharply, living organisms may experience difficulties in obtaining food or other resources. They are forced to get used to other conditions. Anyone who does this better, will be able to survive, and therefore, will give the offspring stronger genes.

Natural selection is one of the engines of evolution. In the course of adaptation to changing conditions, living organisms develop new adaptations and mechanisms. They can change their behavior or their appearance, and over time they are very different from their ancestors.

Examples of natural selection in animals

Natural selection is a kind of competition within one species. One of his options is sexual selection, which practically exists for everyone. Animals do not realize what the biological significance of natural selection is and what it is. However, constantly follow its laws.

Female birds choose a partner with a brighter feathers. Other animals are guided by the size of tails, horns. Often, males have to prove their superiority in a marriage dance or a duel with an opponent.

An example of natural selection is the adaptation of insects to pesticides. The use of the same substances for the destruction of pests often leads to the development of their immunity and resistance to drugs.

Many inhabitants of the deserts were forced to develop special adaptations in order to survive in harsh conditions. The absence of regular precipitation led to the formation of humps in camels. Easier to navigate the sand lizards help scales on their paws, tush-pups - long jumps, and snakes and did learn to crawl.

Examples in plants

Plants adaptability mechanisms are in no way inferior to animals. Cacti, for example, had spines. They occupy a smaller area than the leaves, and prevent the rapid evaporation of moisture.

Other examples of natural selection in plants can be found in any forest where competition is active. In the shady area, low and weaker trees will usually grow than those that grow on sunny terrain. The latter will receive more light and heat, which means they have more chances for full-fledged development.

Of course, this example works only for light-loving plants. The species that formed in the humid and shady areas have long adapted to these conditions. As a result of natural selection, they developed broad leaves. They rarely blossom, as they do not get enough sunlight.