Bacteria are all around us, in fact, they live inside the human body, and in great numbers.Because of their small size can not be seen with the naked eye, yet they can generate both significant harm and benefit.In general, the role of bacteria in nature is enormous.
classification of living things
For a long time did not exist any coherent system, differing organisms.However, the famous Carl Linnaeus laid the foundation for modern binomial classification, divided into 3 main, in his opinion, groups: animals, plants and minerals.He also has suggested the term "kingdom".
In the future, as technology advances and acquire new knowledge, improved classification were isolated prokaryotes and eukaryotes, which is the main difference from each other was the absence and the presence of cells in the nucleus.Today, 8 isolated kingdoms, with significant differences: viruses, archaea, protists, chromium, plants, fungi, animals and bacteria.Regarding the latter, we all know of their existence and are constantly faced with them, although we do not see.It may even seem strange that they were isolated in a separate kingdom of nature.
Bacteria
These simple representatives of nature for a long time, "hidden" from the eyes.Nevertheless, the results of their work were evident in ancient times: the turned sour milk, rotting fallen leaves, fermentation of sugars and more.So that the value of bacteria in nature, even long before their immediate opening overestimated.
This group of organisms is one of the oldest in the world - there are more than 3.5 billion years old, and about one-third of this period, they were the only living creatures on Earth.Despite the fact that evolution somehow also affected them, the structure of bacteria remains fairly primitive, because they do not even have a nucleus.And those members of the kingdom, that are able to survive in the most extreme conditions and at all can be attributed to the simple.However, they are also the largest group of organisms of all existing in the world.
discovery and study
For a long time, scientists did not even know of the existence of organisms that they were not visible.Of course, the discoverer of the bacteria in the XVII century was the man who invented the microscope - a native of Holland, Antony van Leeuwenhoek.His equipment allowed to increase to 160 times so that scientists noticed drops of water, mud, plaque and many other environments, strange creatures - he called them animalkulyami.In the course of research he came across as different and similar organisms, and it is carefully sketched them.Thus were laid the foundations of microbiology.So the name "bacterium" was proposed by Christian Ehrenberg in 1828.
about the relationship of these organisms with various diseases for the first time at the end of the XVIII century, said a military doctor, DS Samoilovich.With the help of a microscope, he tried to find the causative agent of plague, with which he had to face during the epidemic in Moscow.Despite the fact that he has failed, he proved that the infection occurs only through direct contact with sick or things.At the same time, and it proposed the idea of vaccinations by the weakened or killed microorganism.Later, it was realized in England, when the doctor Edward Jenner noticed immunity to smallpox patients after a cow in history.
During the next few decades, microbiology mainly engaged in the collection and systematization of information, to identify the role of bacteria in nature and various life processes.Then there was a distinction of viruses because of the major differences in the structure.But positive bacteria in the life of nature was not immediately appreciated.
Features
In connection with the need to adapt to survive in many different conditions, bacteria not only have to have the ability to proliferate, but also has some variety, which will be discussed later.
All organisms belonging to this realm, of course, have common features.For example, they are prokaryotes, i.e. have a separate kernel and other cell organelles.Meanwhile, according to size, they are typically larger than eukaryotes, and reaches approximately 0.005 millimeters.The biggest known to science bacterium does not exceed 0.75 mm in diameter, while it is even possible to see with the naked eye.
First of all representatives of this kingdom have a cell wall that gives the cell shape, as well as a special mucous capsule protects the organism from drying out and contributes to its sliding motion.Sometimes the thickness of this layer may be greater than that of the rest of the bacteria.Cytoplasm, compared to cells of other microorganisms, more dense and structured.All the nutrients are located directly in it, because there are no vacuoles.Another body, helps cells to move, can be presented on the surface of the fibers.But they can not be removed.
Bacteria Species Wildlife differ primarily in the form of cells, and so they are divided into groups according to how they look.The main types are so called:
- cocci;
- bacilli;
- vibrio;
- spirochetes;
- spirillum;
- streptococci;
- staphylococci.
In addition, there is a distinction by type of conditions suitable for life.Here is an example.Those organisms which may exist in the absence of oxygen are called anaerobes.Furthermore, microbiologists distinguish Gram negative and Gram positive bacteria.Here it is only the response to the special dye, which depends on the structure of the cell membrane.Gram negative bacteria have a thicker protective shell.
Distribution
They live everywhere, and so are forced to make such a volatile form.Volcanoes and ice deserts, sea depths and mountain areas, oxygen-poor - anywhere you can find bacteria.This is only possible thanks to their amazing vitality and rapid reproduction: simple division can occur about every 20 minutes.
way, in conditions that are totally unsuitable for the continuation of life, bacteria, living nature can form the so-called debate, that is to go into a form suitable for transport by wind or water.When the environment is once again becoming quite favorable, microorganisms again take vegetative form and give rise to a new colony.This keeps the spread of bacteria and extends in nature.
importance and role
importance of what makes these tiny organisms, it is difficult to overestimate.The role of bacteria in nature is enormous.First of all, it is to them we owe the existence of complex life forms in their current form.After all, blue-green algae is often referred to as cyanobacteria, in fact, created an atmosphere of support and the level of oxygen at the required level.Until now, these microorganisms living deep in the world's oceans generate more than half of O2.
Perhaps the second most important significance of bacteria in nature - it is their participation in the recycling of organic matter.Without it is also difficult to imagine the modern world.There is a whole class of organisms saprophytes (which includes and bacteria).They are directly involved in the circulation of substances in nature, the remains of decomposing organic tissues to the minerals needed for plant nutrition.So what are these "chips" are an integral part of any ecosystem.
Another important role of bacteria in the nature is to transform one substance to another, though it is not always desirable.Yeast dough and allow to obtain alcohol and lactic acid bacteria - yogurt, cottage cheese, yogurt, and other similar products.But that's not all.Think about bacteria making up the intestinal microflora of mammals.They allow the digestive system so effectively absorb nutrients entering the body with food.
Protection
However, the role of bacteria in the nature of some positive aspects is not limited.So, there are pathogens that cause serious diseases, so often there is a necessity in getting rid of unwanted "guests".For this purpose there is not only an elementary hygiene, that is, hand washing with soap and body, but also disinfection and sterilization of various objects and surfaces.Measures to protect against bacteria may include boiling and prolonged exposure to hot steam, treating the solution with alcohol or chlorine compounds, as well as ultraviolet light.If done correctly, most of the disease-causing cells are killed.
As for food, they are also subjected to various methods of treatment: pasteurization, preservation, boiling, frying, sautéing, baking, and so on. D. This allows you to extend the shelf life and make safe for human consumption.But comprehensive protection from bacteria can have a downside: due to lack of the need to always be ready immune system can weaken.So too zealous in the war against bacteria is not necessary.
