In nature, there are living organisms whose sizes 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?
A microorganism is a collective name. The most characteristic microbe size is less than 0.1 mm. From here came its name. Microorganisms are basically the simplest. According to biologists, this cohort includes non-nuclear (archaea and bacteria), and eukaryotes, as well as some fungi, algae. But not viruses, which scientists usually single out as a separate group.
Design
Almost every microorganism is a unicellular construct, skillfully invented and shaped by nature. As a rule, microbes consist of one cell. But there are exceptions: there are 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.
Habitat
Bacteria are very unpretentious microorganisms. They can survive in conditions unsuitable for the existence of other living beings. Bacteria live on land, and on the sea, and 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 contains nutrients, the humidity is sufficient for living, direct sunlight does not fall (since these microscopic creatures are very afraid of ultraviolet radiation, which is used in medicine for disinfection).
In the soil
Of course, the largest number of bacteria is in the soil. In natural humus, almost ideal conditions for the life of unicellular organisms are almost perfect. There is plenty of food, moderate humidity, and there is no direct sunlight. If the conditions are suitable, more than one type of microorganism can settle and multiply in the soil. These are mainly saprophytes and saprophages - bacteria that participate in the cycle of substances in nature, decompose the dead remains of other organisms, and provide nutrition to plants. The composition of this microflora is quite diverse and is represented by many types of microbes. These are archebacteria, spirochetes, and blue-green algae. Mushrooms and viruses also live here. It is known that in sandstones the predominant amount of aerobic, and in loams - anaerobic. The number of bacteria in the soil breaks all records. In one gram of humus (according to the method of staining microbes invented by Vinogradsky), you can find hundreds of millions of creatures 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 chernozems, the number of these creatures can reach up to two billion per gram of soil. In fact, the bacteria themselves create it without stopping biological processes and transformation of substances for a minute.
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 open spaces (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 can not do without. Yes, and food in lakes and rivers, seas and oceans for many bacteria abound. So, with adequate nutrition, millions of microorganisms can be found in several grams of water. Among them - and especially dangerous to humans.
- Salmonella stimulates intestinal infections. When a person is affected, pain in the digestive tract, fever, and vomiting can occur. As a fight against a dangerous microorganism, the influence of ultraviolet rays and long boiling are actively used.
- Shigella is the causative agent of dysentery. With damage, the body's resistance decreases, immunity falls. The main symptoms are vomiting, nausea, and diarrhea. For disinfection, heat treatment with prolonged boiling and filtration are also used.
- Vibrio cholera. Although it is believed that in our time the disease, in general, has been defeated, this bacterium is still found in nature (in the aquatic, for example, the environment) and poses a certain threat to human lives. Prevention - boiling, filters, ultraviolet.
Also, many bacteria are present in the air, but they use this medium mainly for moving in space, settling new territories. With the smallest particles of dust and moisture, bacteria seem to soar into the air, sometimes overcoming great distances, fall out with the sediments onto the soil and there they already form their colonies.
Blue green algae
Of the variety of microorganisms living in water, it is possible to 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 pigments chlorophyll and phycocyan, giving such a blue-green color. These bacteria are quite widespread in nature. Their habitat is water basins, coastal part, moist rocks, tree bark, soil. They include many varieties. But the main feature and significance of the 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.
Conditionally pathogenic microorganisms
These are mainly microbes that, under certain conditions, can be harmful, but under normal conditions “remain neutral.” There are quite a few such creatures of nature in the human body; they make up its microbial microflora. These are enterococci, E. coli, staphylococci and fungi, which under certain conditions can become pathogenic, that is, pathogenic. But in a healthy person with good immunity, this usually does not happen.