The role of bacteria in nature. The spread of bacteria in nature

Bacteria surround us everywhere, moreover, they live inside the human body, and in huge numbers. Because of their small size, they can not be seen with the naked eye, nevertheless they can bring both tangible harm and benefit. In general, the role of bacteria in nature is enormous.

Classification of living beings

For a long time there was no harmonious system at all, distinguishing organisms. However, the famous Karl Linnaeus laid the basis for modern binomial classification, highlighting the three main, in his opinion, groups: animals, plants and minerals. He also proposed the term "kingdom".

Later, with the development of technology and the acquisition of new knowledge, the classification was improved, prokaryotes and eukaryotes were isolated , the main difference being the absence and presence of nuclei in the cells. Today, there are eight kingdoms that have significant differences: viruses, archaea, protista, chromites, plants, fungi, animals and bacteria. As for the latter, we all know about their existence and are constantly confronted with them, although we do not see it. It may even seem strange that they were separated into a separate kingdom of nature.

Bacteria

These simplest representatives of wildlife for a long time, "hiding" from human eyes. Nevertheless, the results of their activities were evident already in antiquity: sour milk, decay of fallen leaves, fermenting of sugar and much more. So the importance of bacteria in nature, even long before their immediate discovery, is difficult to overestimate.

This group of organisms is one of the oldest on the planet - they exist over 3.5 billion years, and about a third of that time they were the only living beings on Earth. Despite the fact that evolution somehow affected them, the structure of bacteria remains fairly primitive, because they do not even have a nucleus. And those representatives of this kingdom that are able to survive in the most extreme conditions, and at all can be attributed to the simplest. At the same time they are the most numerous group of organisms from all that exist on the Earth.

Discovery and study

For a long time scientists did not even suspect the existence of organisms that were not visible to them. Of course, the discoverer of bacteria in the XVII century was a man who invented a microscope - a native of Holland, Antony van Leeuwenhoek. His instruments gave an increase up to 160 times, so that the scientist noticed in droplets of water, mud, plaque and many other environments of strange creatures - he called them animalculi. During the research, he came across as different, and similar organisms, and he carefully sketched them. So the foundations of microbiology were laid. The very name "bacteria" was proposed by Christian Ehrenberg in 1828.

The connection of these organisms with various diseases for the first time at the end of the XVIII century was declared by the military doctor DS Samoilovich. Using a microscope, he tried to find the causative agent of the plague, which he had to face during the epidemic in Moscow. Despite the fact that he did not succeed, he proved that infection occurs only when he or she directly contacts the patient or his things. At the same time, the idea of vaccinations through weakened or killed microorganisms was proposed. Later it was implemented in England, when the doctor Edward Jenner noticed the patient's immunity to smallpox after the cow's history.

Further for several decades, microbiology was primarily concerned with collecting and systematizing information, revealing the role of bacteria in nature and various life processes. Then there was a demarcation between them and viruses due to serious differences in the structure. But the positive significance of bacteria in the life of nature was not appreciated at once.

Features

In connection with the need to adapt to survival in a wide variety of conditions, the bacteria not only have the ability to reproduce rapidly, but also differ in some diversity, which will be discussed later.

All organisms related to this kingdom, of course, have common features. For example, all of them are prokaryotes, that is, they do not have a separate nucleus and some other cellular organelles. Meanwhile, in size, they are usually larger than eukaryotes, and reach about 0.005 millimeters. The largest bacterium known to science does not exceed 0.75 mm in diameter, and it can even be seen with the naked eye.

First of all, representatives of this kingdom have a cell wall, giving the cell a shape, as well as a special mucous capsule, which protects the body from drying and contributes to its sliding movement. Sometimes the thickness of this layer can be greater than that of the rest of the bacterium. The cytoplasm, in comparison with the cells of other microorganisms, is more dense and structured. All nutrients are located directly in it, since there are no vacuoles. Another organ that helps the cell move can be represented by villi on its surface. But they may be absent.

Varieties

Bacteria of wildlife differ primarily in the form of cells, so they are divided into groups according to how they look. The main types are called so:

• Cocci;
• Bacilli;
• Vibrios;
• Spirochetes;
• Spirilla;
• Streptococci;
• Staphylococci.

In addition, there is a distinction according to the type of conditions suitable for life. Let us give an example. Those organisms that can exist in the absence of oxygen are called anaerobic. In addition, microbiologists distinguish gram-negative and gram-positive bacteria. Here we are talking only about the reaction to a special dye, which depends on the structure of the cell membrane. Gram-negative bacteria have a thicker protective coat.

Spread

They live everywhere, that's why they are forced to take such changeable forms. Vents of volcanoes and icy deserts, sea depths and mountainous terrain, poor in oxygen - bacteria can be found everywhere. This is possible only due to their tremendous vitality and rapid reproduction: simple division can occur about every 20 minutes.

By the way, in conditions that are absolutely not suitable for the continuation of life, the bacteria of living nature can form the so-called spores, that is, go into a form suitable for carrying by wind or water. When the environment again becomes sufficiently favorable, the microorganisms again take on a vegetative form and give rise to a new colony. This is how the spread of bacteria in nature continues and continues.

Meaning and role

The importance of what these tiny organisms do is difficult to overestimate. The role of bacteria in nature is truly enormous. First of all, it is they who are responsible for the existence of complex forms of life in their present form. After all, blue-green algae, as cyanobacteria are often called, actually created an atmosphere and maintain the level of oxygen at the required level. Until now, these microorganisms, living in the thickness of the world's oceans, generate more than half of O ₂ .

Perhaps the second most important bacteria in nature is their participation in the utilization of organic matter. Without this, it is also difficult to imagine the modern world. There is a whole class of organisms-saprophytes (which include bacteria). They are directly involved in the cycle of substances in nature, decomposing the remains of organic tissues to the mineral substances necessary for plant nutrition. So these "crumbs" are an integral part of any ecosystem.

Another important role of bacteria in nature is to convert certain substances into others, although this is not always desirable. Yeast allows you to get dough and alcohol, and lactobacillus bacteria - kefir, cottage cheese, curdled milk and other similar products. But even that is not all. Remember the bacteria that make up the intestinal microflora in mammals. It is they that enable the digestive system to absorb so effectively useful substances that enter the body with food.

Protection

However, the role of bacteria in nature is not limited to positive ones. So, there are pathogens that cause severe diseases, so often there is a need to get rid of unwanted "guests." For this, there is not only basic hygiene, that is, washing hands and bodies with soap, but also disinfection, as well as sterilization of various objects and surfaces. Measures to protect against bacteria can include boiling and prolonged exposure to hot steam, treatment with alcohol solutions or chlorine compounds, and ultraviolet. If everything is done correctly, most of the pathogenic cells die.

As for food, they are also subjected to various methods of processing: pasteurization, preservation, boiling, frying, stewing, baking, etc. This allows to prolong the period of their storage and make them safe for consumption in food. But comprehensive protection against bacteria can have a downside: due to the lack of the need to always be ready, the immune system may be weakened. So do not be too zealous in the war against bacteria.