In nature, there are living organisms whose dimensions are so small that it is simply impossible to see them with the naked eye. They are observed by scientists only with the help of high-magnification microscopes (respectively, they were discovered only with the invention of these devices).
Who are they?
Microorganism is a collective name. The most characteristic size of a microbe is less than 0.1 mm. Hence its name came from. Microorganisms are the simplest. According to biologists, this cohort includes non-nuclear (archaea and bacteria) and eukaryotes, as well as some fungi and algae. But not viruses, which scientists usually classify as a separate group.
Design
Almost every microorganism is a single-cell construct, skillfully conceived and shaped by nature. As a rule, microbes consist of one cell. But there are exceptions: there are also multicellular ones among them, which are a collection of cells, a chain, for example. By the way, there are macroorganisms on Earth that are visible to the naked eye, but consisting of one cell.
Wednesdayhabitat
Bacteria are very unpretentious microorganisms. They can survive in conditions unsuitable for the existence of other living beings. Bacteria live on land, at sea, in the air, and in the bodies of other organisms. For bacteria, it is important that the habitat meets their requirements as much as possible: the substrate contained nutrients, the humidity was sufficient for living, direct sunlight did not fall (since these microscopic creatures are very afraid of exposure to ultraviolet radiation, which is used in medicine for disinfection).
In the soil
Certainly, the largest number of bacteria is in the soil. In natural humus, there are almost ideal conditions for the life of unicellular organisms. There is plenty of food, moderate humidity, and no direct sunlight. If the conditions are right, more than one type of microorganism can settle and multiply in the soil. These are mainly saprophytes and saprophages - bacteria involved in the cycle of substances in nature, decomposing the dead remains of other organisms, giving nutrition to plants. The composition of this microflora is quite diverse and is represented by many types of microbes. These are archaebacteria, and spirochetes, and blue-green algae. Fungi and viruses also live here. It is known that in sandstones the predominant amount is aerobic, and in loams - anaerobic. The number of bacteria in the soil breaks all records. In one gram of humus (according to the microbial staining method invented by Vinogradsky), hundreds of millions can be found.beings invisible to the naked eye. In order to "count" organisms, they are stained with a special composition, and then they become clearly visible under a microscope. And in rich black soil, the number of these creatures can reach up to two billion per gram of soil. Actually, the bacteria themselves create it, not for a minute stopping biological processes and the transformation of substances.
In water and air
A microorganism is an unpretentious creature. As we already know, bacteria can live in any environment that seems more or less attractive to them. This also applies to water expanses (especially when there is no active movement of water). Here, microbes are satisfied with one of the main parameters - the presence of moisture, without which they cannot do without. Yes, and there is plenty of food in lakes and rivers, seas and oceans for many bacteria. So, with sufficient nutrition, a few grams of water can contain millions of microorganisms. Among them are especially dangerous for humans.
- Salmonella causes intestinal infections. With a lesion, a person may experience pain in the gastrointestinal tract, fever, vomiting. As a fight against a dangerous microorganism, exposure to ultraviolet rays and long boiling are actively used.
- Shigella is the causative agent of dysentery. With the defeat, the level of resistance of the body decreases, immunity decreases. Main symptoms: vomiting, nausea, diarrhea. For disinfection, heat treatment with prolonged boiling, filtration are also used.
- Vibrio cholera. Although it is believed that in our time the disease is generally defeated, this bacterium is still found in nature (in the aquatic environment, for example) and poses a certain threat to human life. Prevention - boiling, filters, ultraviolet.
Also, many bacteria are present in the air, but they use this environment mainly to move in space, to populate new territories. With the smallest particles of dust and moisture, the bacteria, as it were, soar into the air, sometimes overcoming great distances, fall along with precipitation to the soil and already form their colonies there.
Blue-green algae
Of the variety of microorganisms living in the water, one can distinguish especially blue-green algae. By the way, they were called algae by mistake, they belong to bacteria and are now called cyanobacteria. This microorganism is a direct descendant of stromatolites, bacteria that lived on the planet more than three billion years ago. Cyanobacteria are the only bacteria capable of photosynthesis, the result of which is the formation of oxygen. They include the pigments chlorophyll and phycocyanin, which give such a blue-green color. These bacteria are quite widespread in nature. Their habitat is water basins, coastal part, damp rocks, tree bark, soil. They include many varieties. But the main feature and significance of blue-green algae that live everywhere is the release of oxygen as a result of photosynthesis. So they directly, along with other representatives of the flora,participate in the formation of the Earth's atmosphere. And in ancient times, according to modern scientists, the ancestors of these microorganisms literally gradually created the atmosphere of our planet.
Opportunistic pathogens
These are mostly microbes that under certain conditions can cause harm, but under normal conditions "keep neutral". There are quite a lot of such creatures of nature in the human body, they make up its microbial microflora. These are enterococci, Escherichia coli, staphylococci and fungi, which under certain conditions can become pathogenic, that is, pathogenic. But in the body of a he althy person with good immunity, this usually does not happen.
