Everyone knows that the infinitely diverse nature surrounding us is divided into living and nonliving. Already in ancient times, it was quite clear to people that any living organism is very different from any inanimate body. By modern ideas it is impossible to point to just one main feature, by which living and nonliving things are distinguished. Modern science says that there are several such signs and the most important are the following:
1. Living organisms are characterized by a much more complex structure than inanimate bodies. 2. To maintain its vital functions, any organism receives energy from environment. Most organisms directly or indirectly use solar energy. 3. Living organisms actively respond to their environment. If, for example, you push a stone, it will move passively, but if you push an animal, it will react actively: it will run away, attack, change shape, and so on. The ability to respond to external stimuli is a universal property of living beings, both plants and animals. 4. Living organisms can not only change, but also become more complex. So, for example, a plant has new branches, and an animal has new organs, significantly different in appearance, and by design from those who gave birth to them. 5. All living things reproduce. Moreover, the offspring are similar to their parents, and at the same time different from them in some way. 6. The similarity of the offspring with their parents is due to another important feature living organisms - the ability to transmit to their descendants the hereditary information contained in them, which is contained in genes(from Greek genos- “origin”) - the smallest and very complex particles found in the nuclei of cells of living organisms. Genetic material directs the development of an organism. This is why offspring look like their parents. However hereditary information during the life of the organism, as well as during transmission, it is somewhat distorted or changed. In this regard, descendants are not only similar to their parents, but also different from them. 7. Living organisms are well adapted to their environment. The structure of a bird, fish, frog, earthworm fully corresponds to the conditions in which they live. This cannot be said about inanimate bodies: a stone, for example, “doesn’t care” where it is - it can lie at the bottom of a river, or lie in a field, or fly from a sling. However, if we force a bird to swim in the depths of the river, and a fish to crawl through the forest, then these living creatures, of course, will die. Simply put, the main differences between living and nonliving things are that all living organisms eat, breathe, grow and reproduce, while non-living bodies do not eat, breathe, grow or reproduce.
In addition, there are much more living organisms on the planet than inanimate objects. To date, scientists have discovered and described more than a million animal species, about half a million plant species, several hundred thousand species of fungi, and more than three thousand species of bacteria. Moreover, the world of living nature has not been fully explored. The number of living species that have not yet been described is estimated at at least a million. In addition, a huge number of species of living organisms have long since become extinct. According to modern scientific data, during the entire development of life on Earth, there have been approximately 500 million species of living beings. People have long tried to explain the diversity of the living world. For several millennia, a very simple explanation prevailed: that all types of organisms were created once by God in their present forms and were never changed again. Supporters of religious ideas believe that all the diversity of organisms inhabiting the Earth was the result of the Divine creation of the world in six days (as it is said in the Bible). Let us remember that classical natural science considered inanimate nature as something unchangeable, created once and for all by God. It was under the influence of the idea of the immutability of all living things that biology - the science of life - for a long time was reduced only to the description of numerous species of animals and plants. And indeed, if you know where it came from Live nature, and also the fact that it is unchangeable, then all that remains is to describe it, to divide, for convenience, all living things into large groups or classes, that is, create its classification. The most advanced classification for its time was created by the famous Swedish scientists XVIII V. Carl Linnaeus.
However, in the same XVIII century. some scientists (for example, Georges Buffon in France, Erasmus Darwin - the grandfather of Charles Darwin - in England, Johann Goethe in Germany, Mikhail Lomonosov in Russia) came to the conclusion that the organisms inhabiting the Earth are not unchanged, but are in a state continuous development. The process of change or development is called in science evolution(from lat. evolutio– “deployment”). They were allowed to draw this conclusion by the findings in different places our planet, the remains of animals and plants that existed on Earth millions of years ago. They seemed strange, since they were completely different from modern living organisms. From this difference between ancient and modern forms of life, we can conclude that living nature is constantly evolving.
One of the first to try to figure out the course of evolution was the famous French biologist of the 18th century. Jean Lamarck. (It was he who first proposed the term “biology.”) Lamarck explained the change in the species of living organisms by the fact that they are significantly influenced by the environment (nutrition, climate, etc.), under the influence of which new characteristics are formed, as well as by that they are inherited from one generation to another, gradually leading to the formation of new species of living organisms. The creator of a harmonious and detailed theory of evolution is the famous English scientist Charles Darwin, who generalized in the middle of the 19th century. separate evolutionary ideas into a single doctrine. Since then, this theory has remained the most fruitful result of biological thought throughout its existence. It is true that from time to time thinkers appear who declare that Darwin was wrong. However, they cannot offer anything worthy in return for his ideas. Until now, no other theory of any significance has appeared that would explain many mysterious facts, as Darwin's theory of evolution did. Moreover, today it is finding more and more new areas of application.
Charles Darwin (1809–1882)
The development of any species of living organisms, says Darwin, occurs in the following way. Since the conditions of their habitat (landscape, climate) are constantly changing, it is not surprising that various changes occur in living organisms that adapt to new conditions in order to survive. That is, some characteristics that are beneficial for the old conditions disappear, and others appear that are more compatible with the new ones. These characteristics are inherited by subsequent generations, fixed in them, ensuring the survival of the species, and are preserved until changing environmental conditions make them unprofitable or disastrous. Let's give a simple example. To where the gray caterpillars lived, feeding on tree leaves, birds flew in from somewhere and began to eat the caterpillars. The gray caterpillars were clearly visible on the green leaves of the trees and became easy prey for birds. To survive, the caterpillars changed their color from gray to green to blend in with the leaves and be invisible. This is how a new trait is formed under the influence of changed environmental conditions. However, not all individuals are able to quickly change color, and therefore those who have new sign appeared faster, have more chances for survival. Their still gray relatives are doomed to death. Consequently, green caterpillars survive, which, by reproducing, will pass on this vital important sign. Thus, variability (a change in any characteristic or characteristics that has occurred) is fixed in subsequent generations by heredity. Let us pay attention to the fact that some of the individuals who have not adapted to the new conditions die, but, on the contrary, the most adapted ones survive, having developed new characteristics that are beneficial for life, which allow them not only to survive, but also to reproduce and leave behind offspring. In other words, nature itself selects the strongest and most adapted organisms for life, destroying the weak and unadapted. Such selection in evolutionary theory called natural. He is, according to Darwin, the main driving force evolution, its universal law, to which the development of all living nature is subject. Variation, heredity and natural selection have been in effect since the time immemorial of the appearance of living things and have led to the now astounding diversity of species of living organisms.
Among Darwinian ideas there is also the statement that man, as one of the biological species (called Homo sapiens), is the result of a long evolution of living nature from less perfect to more perfect organisms. Quite often you can hear that, from Darwin’s point of view, man descended from apes. This statement is incorrect, it greatly coarsens and distorts his thought. By the way, when we are told that man descended from a monkey, a fair question often arises: why don’t today’s monkeys turn into people? So, it is more correct to say that both humans and modern apes descended from common mammalian ancestors who lived many millions of years ago. This statement can be illustrated by the so-called “five-finger principle.” Look at your palm: four fingers are directed in one direction, and one - the thumb - in the other, as if it is opposed to all the others. Approximately the same thing is observed in the scheme of human evolution: from the common mammal ancestor, a branch of evolution went in one direction, which led to the appearance of monkeys, and in the other direction, an evolutionary branch went in the other direction, culminating in the appearance of a special biological species- a reasonable person. This separation of the two branches occurred approximately 10-15 million years ago, and therefore it is quite clear that ape and man are completely different different types, not so much similar as opposed to each other (look again at the five fingers of the palm), just as it is clear that man did not “descend from a monkey” (and it is also not at all surprising why modern monkeys do not turn into people).
In conclusion, it should be noted that, despite huge successes biology, many questions and problems related to the origin of life on Earth and human evolution are still far from final decision and are waiting for their future researchers. The enormous and undoubted merit of Darwin's theory, among other things, lies in the fact that it made the first hole in the idea of stationarity of the inanimate and living world, which had prevailed for several centuries. The doctrine of evolution seemed to fall out of classical mechanistic natural science, which asserted the immutability of everything that exists. Half a century after its creation evolutionary doctrine second, or classic, scientific picture The world began to collapse, giving way to the third, or non-classical, one of the main ideas of which was the assertion that not only living nature, but the Universe as a whole is the result of a grandiose world evolution.
Modern era
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