Do bacteria live in hot springs? Thermal water organisms Animals living in hot springs.

Extremophiles are organisms that live and thrive in habitats where life is impossible for most other organisms. The suffix (-phil) in Greek means love. Extremophiles “love” to live in extreme conditions. They have the ability to withstand conditions such as high radiation, high or low pressure, high or low pH, lack of light, extreme heat or cold, and extreme drought.

Most extremophiles are microorganisms such as, and. Larger organisms such as worms, frogs, and insects can also live in extreme habitats. There are different classes of extremophiles based on the type of environment in which they thrive. Here are some of them:

• An acidophilus is an organism that thrives in an acidic environment with pH levels of 3 and below.
• Alkaliphile is an organism that thrives in alkaline environments with pH levels of 9 and above.
• Barophil is an organism that lives in high pressure environments such as deep sea habitats.
• A halophile is an organism that lives in habitats with extremely high salt concentrations.
• A hyperthermophile is an organism that thrives in environments with extremely high temperatures (80° to 122° C).
• Psychrophile/cryophile - an organism that lives in extremely cold conditions and low temperatures (from -20° to +10° C).
• Radioresistant organisms are organisms that thrive in environments with high levels of radiation, including ultraviolet and nuclear radiation.
• A xerophile is an organism that lives in extremely dry conditions.

Tardigrades

Tardigrades, or water bears, can tolerate several types of extreme conditions. They live in hot springs, Antarctic ice, as well as in deep environments, on mountain tops and even in... Tardigrades are commonly found in lichens and mosses. They feed on plant cells and tiny invertebrates such as nematodes and rotifers. Aquatic bears reproduce, although some reproduce through parthenogenesis.

Tardigrades can survive in a variety of extreme conditions because they are able to temporarily shut down their metabolism when conditions are not suitable for survival. This process is called cryptobiosis and allows aquatic bears to enter a state that allows them to survive in conditions of extreme aridity, lack of oxygen, extreme cold, low pressure and high toxicity or radiation. Tardigrades can remain in this state for several years and exit it when the environment becomes habitable.

Artemia ( Artemia salina)

Artemia is a species of small crustacean that can live in conditions with extremely high salt concentrations. These extremophiles live in salt lakes, salt marshes, seas and rocky shores. Their main food source is green algae. Artemia have gills that help them survive in salty environments by absorbing and releasing ions and producing concentrated urine. Like tardigrades, brine shrimp reproduce sexually and asexually (via parthenogenesis).

Helicobacter pylori bacteria ( Helicobacter pylori)

Helicobacter pylori- a bacterium that lives in the extremely acidic environment of the stomach. These bacteria secrete the enzyme urease, which neutralizes hydrochloric acid. It is known that other bacteria are not able to withstand the acidity of the stomach. Helicobacter pylori are spiral-shaped bacteria that can burrow into the stomach wall and cause ulcers or even stomach cancer in humans. Most people in the world have this bacteria in their stomachs, but they typically rarely cause illness, according to the Centers for Disease Control and Prevention (CDC).

Cyanobacteria Gloeocapsa

Gloeocapsa- a genus of cyanobacteria that usually live on wet rocks of rocky shores. These bacteria contain chlorophyll and are capable of... Cells Gloeocapsa surrounded by gelatinous membranes that can be brightly colored or colorless. Scientists have discovered that they are able to survive in space for a year and a half. Rock samples containing Gloeocapsa, were placed outside the International Space Station, and these microorganisms were able to withstand the extreme conditions of space, such as temperature fluctuations, vacuum exposure and radiation exposure.

Temperature is the most important environmental factor. Temperature has a huge impact on many aspects of the life of organisms, their geography of distribution, reproduction and other biological properties of organisms, which depend mainly on temperature. Range, i.e. The temperature limits in which life can exist range from approximately -200°C to +100°C, and bacteria have sometimes been found to exist in hot springs at temperatures of 250°C. In reality, most organisms can survive in an even narrower range of temperatures.

Some types of microorganisms, mainly bacteria and algae, are able to live and reproduce in hot springs at temperatures close to the boiling point. The upper temperature limit for hot spring bacteria is about 90°C. Temperature variability is very important from an environmental point of view.

Any species is able to live only within a certain temperature range, the so-called maximum and minimum lethal temperatures. Beyond these critical temperature extremes, cold or heat, death of the organism occurs. Somewhere between them there is an optimal temperature at which the vital activity of all organisms, living matter as a whole, is active.

Based on the tolerance of organisms to temperature conditions, they are divided into eurythermic and stenothermic, i.e. able to tolerate temperature fluctuations within wide or narrow limits. For example, lichens and many bacteria can live at different temperatures, or orchids and other heat-loving plants of tropical zones are stenothermic.

Some animals are able to maintain a constant body temperature, regardless of the ambient temperature. Such organisms are called homeothermic. In other animals, body temperature varies depending on the ambient temperature. They are called poikilothermic. Depending on the method of adaptation of organisms to temperature conditions, they are divided into two ecological groups: cryophylls - organisms adapted to cold, to low temperatures; thermophiles - or heat-loving.

Allen's rule- an ecogeographical rule established by D. Allen in 1877. According to this rule, among related forms of homeothermic (warm-blooded) animals leading a similar lifestyle, those that live in colder climates have relatively smaller protruding body parts: ears, legs, tails, etc.

Reducing the protruding parts of the body leads to a decrease in the relative surface of the body and helps to save heat.

An example of this rule are representatives of the Canine family from various regions. The smallest (relative to body length) ears and less elongated muzzle in this family are found in the Arctic fox (area: Arctic), and the largest ears and narrow, elongated muzzle are found in the fennec fox (area: Sahara).

This rule also applies to human populations: the shortest (relative to body size) nose, arms and legs are characteristic of the Eskimo-Aleut peoples (Eskimos, Inuit), and the longest arms and legs are for the Furs and Tutsis.

Bergman's rule- an ecogeographical rule formulated in 1847 by the German biologist Karl Bergmann. The rule states that among similar forms of homeothermic (warm-blooded) animals, the largest are those that live in colder climates - in high latitudes or in the mountains. If there are closely related species (for example, species of the same genus) that do not differ significantly in their feeding patterns and lifestyle, then larger species are also found in more severe (cold) climates.

The rule is based on the assumption that the total heat production in endothermic species depends on the volume of the body, and the rate of heat transfer depends on its surface area. As the size of organisms increases, the volume of the body grows faster than its surface. This rule was first tested experimentally on dogs of different sizes. It turned out that heat production in small dogs is higher per unit mass, but regardless of size it remains almost constant per unit surface area.

Indeed, Bergmann's rule is often fulfilled both within the same species and among closely related species. For example, the Amur form of the tiger from the Far East is larger than the Sumatran form from Indonesia. Northern wolf subspecies are on average larger than southern ones. Among closely related species of the bear genus, the largest ones live in northern latitudes (the polar bear, brown bears from Kodiak Island), and the smallest species (for example, the spectacled bear) live in areas with a warm climate.

At the same time, this rule was often criticized; it was noted that it cannot be of a general nature, since the size of mammals and birds is influenced by many other factors besides temperature. In addition, adaptations to harsh climates at the population and species level often occur not through changes in body size, but through changes in the size of internal organs (increasing the size of the heart and lungs) or through biochemical adaptations. Taking into account this criticism, it is necessary to emphasize that Bergman’s rule is statistical in nature and manifests its effect clearly, all other things being equal.

Indeed, there are many exceptions to this rule. Thus, the smallest race of woolly mammoth is known from the polar island of Wrangel; many forest wolf subspecies are larger than tundra wolves (for example, the extinct subspecies from the Kenai Peninsula; it is assumed that their large size could give these wolves an advantage when hunting large moose inhabiting the peninsula). The Far Eastern subspecies of leopard living on the Amur is significantly smaller than the African one. In the examples given, the compared forms differ in lifestyle (island and continental populations; tundra subspecies, feeding on smaller prey, and forest subspecies, feeding on larger prey).

In relation to humans, the rule is applicable to a certain extent (for example, pygmy tribes apparently appeared repeatedly and independently in different areas with a tropical climate); however, differences in local diets and customs, migration, and genetic drift between populations place limits on the applicability of this rule.

Gloger's rule is that among related forms (different races or subspecies of the same species, related species) of homeothermic (warm-blooded) animals, those that live in warm and humid climates are brighter colored than those that live in cold and dry climate. Established in 1833 by Konstantin Gloger (Gloger C. W. L.; 1803-1863), a Polish and German ornithologist.

For example, most desert bird species are duller in color than their relatives from subtropical and tropical forests. Gloger's rule can be explained both by considerations of camouflage and by the influence of climatic conditions on the synthesis of pigments. To a certain extent, Gloger's rule also applies to hypokilothermic (cold-blooded) animals, in particular insects.

Humidity as an environmental factor

Initially, all organisms were aquatic. Having conquered land, they did not lose their dependence on water. Water is an integral part of all living organisms. Humidity is the amount of water vapor in the air. Without moisture or water there is no life.

Humidity is a parameter characterizing the content of water vapor in the air. Absolute humidity is the amount of water vapor in the air and depends on temperature and pressure. This amount is called relative humidity (i.e., the ratio of the amount of water vapor in the air to the saturated amount of vapor under certain conditions of temperature and pressure.)

In nature there is a daily rhythm of humidity. Humidity fluctuates vertically and horizontally. This factor, along with light and temperature, plays a large role in regulating the activity of organisms and their distribution. Humidity also modifies the effect of temperature.

An important environmental factor is air drying. Especially for terrestrial organisms, the drying effect of air is of great importance. Animals adapt by moving to protected places and leading an active lifestyle at night.

Plants absorb water from the soil and almost all (97-99%) evaporates through the leaves. This process is called transpiration. Evaporation cools the leaves. Thanks to evaporation, ions are transported through the soil to the roots, ions are transported between cells, etc.

A certain amount of moisture is absolutely necessary for terrestrial organisms. Many of them require a relative humidity of 100% for normal functioning, and on the contrary, an organism in a normal state cannot live for a long time in absolutely dry air, because it constantly loses water. Water is an essential part of living matter. Therefore, the loss of water in a certain amount leads to death.

Plants in dry climates adapt through morphological changes and reduction of vegetative organs, especially leaves.

Land animals also adapt. Many of them drink water, others absorb it through the body in liquid or vapor form. For example, most amphibians, some insects and mites. Most desert animals never drink; they satisfy their needs from water supplied with food. Other animals obtain water through the process of fat oxidation.

Water is absolutely necessary for living organisms. Therefore, organisms spread throughout their habitat depending on their needs: aquatic organisms live constantly in water; hydrophytes can only live in very humid environments.

From the point of view of ecological valency, hydrophytes and hygrophytes belong to the group of stenogyrs. Humidity greatly affects the vital functions of organisms, for example, 70% relative humidity was very favorable for field maturation and fertility of female migratory locusts. When propagated successfully, they cause enormous economic damage to crops in many countries.

For ecological assessment of the distribution of organisms, the indicator of climate aridity is used. Dryness serves as a selective factor for the ecological classification of organisms.

Thus, depending on the humidity characteristics of the local climate, species of organisms are distributed into ecological groups:

1. Hydatophytes are aquatic plants.

2. Hydrophytes are terrestrial-aquatic plants.

3. Hygrophytes - terrestrial plants living in conditions of high humidity.

4. Mesophytes are plants that grow with average moisture

5. Xerophytes are plants that grow with insufficient moisture. They, in turn, are divided into: succulents - succulent plants (cacti); sclerophytes are plants with narrow and small leaves, and rolled into tubes. They are also divided into euxerophytes and stypaxerophytes. Euxerophytes are steppe plants. Stypaxerophytes are a group of narrow-leaved turf grasses (feather grass, fescue, tonkonogo, etc.). In turn, mesophytes are also divided into mesohygrophytes, mesoxerophytes, etc.

Although inferior in importance to temperature, humidity is nevertheless one of the main environmental factors. For most of the history of living nature, the organic world was represented exclusively by aquatic organisms. An integral part of the vast majority of living beings is water, and almost all of them require an aquatic environment to reproduce or fuse gametes. Land animals are forced to create an artificial aquatic environment in their bodies for fertilization, and this leads to the latter becoming internal.

Humidity is the amount of water vapor in the air. It can be expressed in grams per cubic meter.

Light as an environmental factor. The role of light in the life of organisms

Light is one of the forms of energy. According to the first law of thermodynamics, or the law of conservation of energy, energy can change from one form to another. According to this law, organisms are a thermodynamic system constantly exchanging energy and matter with the environment. Organisms on the surface of the Earth are exposed to a flow of energy, mainly solar energy, as well as long-wave thermal radiation from cosmic bodies.

Both of these factors determine the climatic conditions of the environment (temperature, rate of water evaporation, movement of air and water). Sunlight with an energy of 2 cal falls on the biosphere from space. by 1 cm 2 in 1 min. This is the so-called solar constant. This light, passing through the atmosphere, is weakened and no more than 67% of its energy can reach the Earth’s surface on a clear noon, i.e. 1.34 cal. per cm 2 in 1 min. Passing through cloud cover, water and vegetation, sunlight is further weakened, and the distribution of energy in it across different parts of the spectrum changes significantly.

The degree to which sunlight and cosmic radiation are attenuated depends on the wavelength (frequency) of the light. Ultraviolet radiation with a wavelength of less than 0.3 microns almost does not pass through the ozone layer (at an altitude of about 25 km). Such radiation is dangerous for a living organism, in particular for protoplasm.

In living nature, light is the only source of energy; all plants, except bacteria, photosynthesize, i.e. synthesize organic substances from inorganic substances (i.e. from water, mineral salts and CO-In living nature, light is the only source of energy, all plants except bacteria 2 - using radiant energy in the process of assimilation). All organisms depend for nutrition on terrestrial photosynthetic organisms, i.e. chlorophyll-bearing plants.

Light as an environmental factor is divided into ultraviolet with a wavelength of 0.40 - 0.75 microns and infrared with a wavelength greater than these magnitudes.

The action of these factors depends on the properties of the organisms. Each type of organism is adapted to a particular wavelength of light. Some types of organisms have adapted to ultraviolet radiation, while others have adapted to infrared radiation.

Some organisms are able to distinguish between wavelengths. They have special light-perceiving systems and color vision, which are of great importance in their life. Many insects are sensitive to short-wave radiation, which humans cannot perceive. Moths perceive ultraviolet rays well. Bees and birds accurately determine their location and navigate the terrain even at night.

Organisms also react strongly to light intensity. Based on these characteristics, plants are divided into three ecological groups:

1. Light-loving, sun-loving or heliophytes - which are able to develop normally only under the sun's rays.

2. Shade-loving plants, or sciophytes, are plants of the lower tiers of forests and deep-sea plants, for example, lilies of the valley and others.

As light intensity decreases, photosynthesis also slows down. All living organisms have threshold sensitivity to light intensity, as well as to other environmental factors. Different organisms have different threshold sensitivity to environmental factors. For example, intense light inhibits the development of Drosophila flies, even causing their death. Cockroaches and other insects do not like light. In most photosynthetic plants, at low light intensity, protein synthesis is inhibited, and in animals, biosynthesis processes are inhibited.

3. Shade-tolerant or facultative heliophytes. Plants that grow well in both shade and light. In animals, these properties of organisms are called light-loving (photophiles), shade-loving (photophobes), euryphobic - stenophobic.

Environmental valence

the degree of adaptability of a living organism to changes in environmental conditions. E.v. represents a species property. It is expressed quantitatively by the range of environmental changes within which a given species maintains normal life activity. E.v. can be considered both in relation to the reaction of a species to individual environmental factors, and in relation to a complex of factors.

In the first case, species that tolerate wide changes in the strength of the influencing factor are designated by a term consisting of the name of this factor with the prefix “eury” (eurythermal - in relation to the influence of temperature, euryhaline - in relation to salinity, eurybatherous - in relation to depth, etc.); species adapted only to small changes in this factor are designated by a similar term with the prefix “steno” (stenothermic, stenohaline, etc.). Species with broad E. v. in relation to a complex of factors, they are called eurybionts (See Eurybionts) in contrast to stenobionts (See Stenobionts), which have low adaptability. Since eurybionticity makes it possible to populate a variety of habitats, and stenobionticity sharply narrows the range of habitats suitable for the species, these two groups are often called eury- or stenotopic, respectively.

Eurybionts, animal and plant organisms capable of existing under significant changes in environmental conditions. For example, the inhabitants of the marine littoral zone endure regular drying during low tide, strong heating in summer, and cooling and sometimes freezing in winter (eurythermal animals); The inhabitants of river estuaries can withstand it. fluctuations in water salinity (euryhaline animals); a number of animals exist in a wide range of hydrostatic pressure (eurybates). Many terrestrial inhabitants of temperate latitudes are able to withstand large seasonal temperature fluctuations.

The eurybiontism of the species is increased by the ability to tolerate unfavorable conditions in a state of anabiosis (many bacteria, spores and seeds of many plants, adult perennial plants of cold and temperate latitudes, wintering buds of freshwater sponges and bryozoans, eggs of branchial crustaceans, adult tardigrades and some rotifers, etc.) or hibernation (some mammals).

CHETVERIKOV'S RULE, As a rule, according to Krom, in nature all types of living organisms are represented not by individual isolated individuals, but in the form of aggregates of numbers (sometimes very large) of individuals-populations. Bred by S. S. Chetverikov (1903).

View- this is a historically established set of populations of individuals, similar in morpho-physiological properties, capable of freely interbreeding with each other and producing fertile offspring, occupying a certain area. Each species of living organisms can be described by a set of characteristic features and properties, which are called characteristics of the species. Characteristics of a species by which one species can be distinguished from another are called species criteria.

The most commonly used are seven general criteria of the form:

1. Specific type of organization: a set of characteristic features that make it possible to distinguish individuals of a given species from individuals of another.

2. Geographical certainty: the existence of individuals of a species in a specific place on the globe; range - the area where individuals of a given species live.

3. Ecological certainty: individuals of a species live in a specific range of values ​​of physical environmental factors, such as temperature, humidity, pressure, etc.

4. Differentiation: a species consists of smaller groups of individuals.

5. Discreteness: individuals of a given species are separated from individuals of another by a gap - hiatus. Hiatus is determined by the action of isolating mechanisms, such as discrepancies in the timing of reproduction, the use of specific behavioral reactions, sterility of hybrids, etc.

6. Reproducibility: reproduction of individuals can be carried out asexually (the degree of variability is low) and sexually (the degree of variability is high, since each organism combines the characteristics of the father and mother).

7. A certain level of numbers: numbers undergo periodic (waves of life) and non-periodic changes.

Individuals of any species are distributed extremely unevenly in space. For example, stinging nettle, within its range, is found only in moist, shady places with fertile soil, forming thickets in the floodplains of rivers, streams, around lakes, along the edges of swamps, in mixed forests and thickets of shrubs. Colonies of the European mole, clearly visible on the mounds of earth, are found on forest edges, meadows and fields. Suitable for life
Although habitats are often found within the range, they do not cover the entire range, and therefore individuals of this species are not found in other parts of it. There is no point in looking for nettles in a pine forest or a mole in a swamp.

Thus, the uneven distribution of a species in space is expressed in the form of “islands of density”, “condensations”. Areas with a relatively high distribution of this species alternate with areas with low abundance. Such “density centers” of the population of each species are called populations. A population is a collection of individuals of a given species, inhabiting a certain space (part of its range) for a long time (a large number of generations), and isolated from other similar populations.

Free crossing (panmixia) practically takes place within the population. In other words, a population is a group of individuals freely joining together, living for a long time in a certain territory, and relatively isolated from other similar groups. A species, therefore, is a collection of populations, and a population is a structural unit of a species.

Difference between a population and a species:

1) individuals of different populations interbreed freely with each other,

2) individuals of different populations differ little from each other,

3) there is no gap between two neighboring populations, that is, there is a gradual transition between them.

The process of speciation. Let us assume that a given species occupies a certain habitat determined by its feeding pattern. As a result of divergence between individuals, the range increases. The new habitat will contain areas with different food plants, physical and chemical properties, etc. Individuals that find themselves in different parts of the habitat form populations. In the future, as a result of the ever-increasing differences between individuals of populations, it will become increasingly clear that individuals of one population differ in some way from individuals of another population. A process of population divergence is taking place. Mutations accumulate in each of them.

Representatives of any species in the local part of the range form a local population. The totality of local populations associated with areas of the habitat that are homogeneous in terms of living conditions constitutes an ecological population. So, if a species lives in a meadow and forest, then they speak of its gum and meadow populations. Populations within a species' range that are associated with specific geographic boundaries are called geographic populations.
Population sizes and boundaries can change dramatically. During outbreaks of mass reproduction, the species spreads very widely and giant populations arise.

A set of geographical populations with stable characteristics, the ability to interbreed and produce fertile offspring is called a subspecies. Darwin said that the formation of new species occurs through varieties (subspecies).

However, it should be remembered that in nature often some element is missing.
Mutations occurring in individuals of each subspecies cannot by themselves lead to the formation of new species. The reason lies in the fact that this mutation will wander throughout the population, since individuals of the subspecies, as we know, are not reproductively isolated. If a mutation is beneficial, it increases the heterozygosity of the population; if it is harmful, it will simply be rejected by selection.

As a result of the constantly occurring mutation process and free crossing, mutations accumulate in populations. According to the theory of I. I. Shmalhausen, a reserve of hereditary variability is created, i.e., the vast majority of mutations that arise are recessive and do not manifest themselves phenotypically. Once a high concentration of mutations in the heterozygous state is reached, crossing of individuals carrying recessive genes becomes possible. In this case, homozygous individuals appear in which the mutations already manifest themselves phenotypically. In these cases, mutations are already under the control of natural selection.
But this is not yet decisive for the process of speciation, because natural populations are open and foreign genes from neighboring populations are constantly introduced into them.

There is a gene flow sufficient to maintain a high similarity of gene pools (the totality of all genotypes) of all local populations. It is estimated that the replenishment of the gene pool due to foreign genes in a population consisting of 200 individuals, each of which has 100,000 loci, is 100 times greater than due to mutations. As a consequence, no population can change dramatically as long as it is subject to the normalizing influence of gene flow. The resistance of a population to changes in its genetic composition under the influence of selection is called genetic homeostasis.

As a result of genetic homeostasis in a population, the formation of a new species is very difficult. One more condition must be met! Namely, it is necessary to isolate the gene pool of the daughter population from the maternal gene pool. Isolation can come in two forms: spatial and temporal. Spatial isolation occurs due to various geographical barriers, such as deserts, forests, rivers, dunes, and floodplains. Most often, spatial isolation occurs due to a sharp reduction in the continuous range and its disintegration into separate pockets or niches.

Often a population becomes isolated as a result of migration. In this case, an isolate population arises. However, since the number of individuals in an isolate population is usually small, there is a danger of inbreeding - degeneration associated with inbreeding. Speciation based on spatial isolation is called geographic.

The temporary form of isolation includes changes in the timing of reproduction and shifts in the entire life cycle. Speciation based on temporary isolation is called ecological.
The decisive thing in both cases is the creation of a new, incompatible with the old, genetic system. Evolution is realized through speciation, which is why they say that a species is an elementary evolutionary system. A population is an elementary evolutionary unit!

Statistical and dynamic characteristics of populations.

Species of organisms enter the biocenosis not as individuals, but as populations or parts thereof. A population is a part of a species (consists of individuals of the same species), occupying a relatively homogeneous space and capable of self-regulation and maintaining a certain number. Each species within the occupied territory breaks up into populations. If we consider the impact of environmental factors on an individual organism, then at a certain level of the factor (for example, temperature), the individual under study will either survive or die. The picture changes when studying the effect of the same factor on a group of organisms of the same species.

Some individuals will die or reduce their vital activity at one specific temperature, others - at a lower temperature, and others - at a higher temperature. Therefore, we can give another definition of a population: all living organisms, in order to survive and give offspring, must, under dynamic environmental conditions factors exist in the form of groups, or populations, i.e. a collection of cohabiting individuals with similar heredity. The most important feature of a population is the total territory it occupies. But within a population there may be groups that are more or less isolated for various reasons.

Therefore, it is difficult to give an exhaustive definition of the population due to the blurred boundaries between individual groups of individuals. Each species consists of one or more populations, and a population is thus the form of existence of a species, its smallest evolving unit. For populations of various species, there are acceptable limits for the reduction in the number of individuals, beyond which the existence of the population becomes impossible. There are no exact data on critical values ​​of population numbers in the literature. The given values ​​are contradictory. However, the fact remains undoubted that the smaller the individuals, the higher the critical values ​​of their numbers. For microorganisms this is millions of individuals, for insects - tens and hundreds of thousands, and for large mammals - several dozen.

The number should not decrease below the limits beyond which the probability of meeting sexual partners sharply decreases. The critical number also depends on other factors. For example, for some organisms a group lifestyle (colonies, flocks, herds) is specific. Groups within a population are relatively isolated. There may be cases when the population as a whole is still quite large, and the number of individual groups is reduced below critical limits.

For example, a colony (group) of a Peruvian cormorant should have a population of at least 10 thousand individuals, and a herd of reindeer - 300 - 400 heads. To understand the mechanisms of functioning and solve issues of using populations, information about their structure is of great importance. There are gender, age, territorial and other types of structure. In theoretical and applied terms, the most important data is on the age structure - the ratio of individuals (often combined into groups) of different ages.

Animals are divided into the following age groups:

Juvenile group (children) senile group (senile group, not involved in reproduction)

Adult group (individuals engaged in reproduction).

Typically, normal populations are characterized by the greatest viability, in which all ages are represented relatively evenly. In a regressive (endangered) population, senile individuals predominate, which indicates the presence of negative factors that disrupt reproductive functions. Urgent measures are required to identify and eliminate the causes of this condition. Invading (invasive) populations are represented mainly by young individuals. Their vitality usually does not cause concern, but there is a high probability of outbreaks of excessively high numbers of individuals, since trophic and other connections have not been formed in such populations.

It is especially dangerous if it is a population of species that were previously absent from the area. In this case, populations usually find and occupy a free ecological niche and realize their reproduction potential, intensively increasing their numbers. If the population is in a normal or close to normal state, a person can remove from it the number of individuals (in animals) or biomass (in plants), which increases over the period of time between withdrawals. First of all, individuals of post-productive age (who have completed reproduction) should be removed. If the goal is to obtain a certain product, then age, gender and other characteristics of populations are adjusted taking into account the task.

The exploitation of populations of plant communities (for example, for timber production) is usually timed to coincide with the period of age-related slowdown in growth (product accumulation). This period usually coincides with the maximum accumulation of woody mass per unit area. The population is also characterized by a certain sex ratio, and the ratio of males and females is not equal to 1:1. There are known cases of a sharp predominance of one sex or another, alternation of generations with the absence of males. Each population can also have a complex spatial structure (divided into more or less large hierarchical groups - from geographical to elementary (micropopulations).

Thus, if the mortality rate does not depend on the age of individuals, then the survival curve is a decreasing line (see figure, type I). That is, the death of individuals occurs evenly in this type, the mortality rate remains constant throughout life. Such a survival curve is characteristic of species whose development occurs without metamorphosis with sufficient stability of the born offspring. This type is usually called the hydra type - it is characterized by a survival curve approaching a straight line. In species for which the role of external factors in mortality is small, the survival curve is characterized by a slight decrease until a certain age, after which there is a sharp drop as a result of natural (physiological) mortality.

Type II in the picture. The nature of the survival curve close to this type is characteristic of humans (although the human survival curve is somewhat flatter and, thus, is something between types I and II). This type is called the Drosophila type: it is what fruit flies exhibit in laboratory conditions (not eaten by predators). Many species are characterized by high mortality in the early stages of ontogenesis. In such species, the survival curve is characterized by a sharp drop in the younger ages. Individuals that survive the “critical” age exhibit low mortality and live to older ages. The type is called the oyster type. Type III in the picture. The study of survival curves is of great interest to the ecologist. It allows us to judge at what age a particular species is most vulnerable. If the effects of causes that can change fertility or mortality occur at the most vulnerable stage, then their influence on the subsequent development of the population will be greatest. This pattern must be taken into account when organizing hunting or pest control.

Age and sex structures of populations.

Any population is characterized by a certain organization. The distribution of individuals over the territory, the ratio of groups of individuals by sex, age, morphological, physiological, behavioral and genetic characteristics reflect the corresponding population structure : spatial, gender, age, etc. The structure is formed, on the one hand, on the basis of the general biological properties of the species, and on the other, under the influence of abiotic environmental factors and populations of other species.

The population structure is thus adaptive in nature. Different populations of the same species have both similar and distinctive features that characterize the specific environmental conditions in their habitats.

In general, in addition to the adaptive capabilities of individual individuals, in certain territories adaptive features of group adaptation of the population as a supra-individual system are formed, which indicates that the adaptive features of the population are much higher than those of the individuals composing it.

Age composition- is important for the existence of a population. The average lifespan of organisms and the ratio of numbers (or biomass) of individuals of different ages are characterized by the age structure of the population. The formation of the age structure occurs as a result of the combined action of the processes of reproduction and mortality.

In any population, 3 age ecological groups are conventionally distinguished:

Pre-reproductive;

Reproductive;

Post-reproductive.

The pre-reproductive group includes individuals that are not yet capable of reproduction. Reproductive - individuals capable of reproduction. Post-reproductive - individuals who have lost the ability to reproduce. The duration of these periods varies greatly depending on the type of organism.

Under favorable conditions, the population contains all age groups and maintains a more or less stable age composition. In rapidly growing populations, young individuals predominate, while in declining populations, older individuals are no longer able to reproduce intensively. Such populations are unproductive and not stable enough.

There are types with simple age structure populations that consist of individuals of almost the same age.

For example, all annual plants of one population are in the seedling stage in the spring, then bloom almost simultaneously, and produce seeds in the fall.

In species with complex age structure populations have several generations living at the same time.

For example, elephants have a history of young, mature and aging animals.

Populations that include many generations (of different age groups) are more stable and less susceptible to the influence of factors affecting reproduction or mortality in a particular year. Extreme conditions can lead to the death of the most vulnerable age groups, but the most resilient survive and give birth to new generations.

For example, a person is considered as a biological species with a complex age structure. The stability of the species' populations was demonstrated, for example, during the Second World War.

To study the age structures of populations, graphic techniques are used, for example, population age pyramids, widely used in demographic studies (Fig. 3.9).

Fig.3.9. Population age pyramids.

A - mass reproduction, B - stable population, C - declining population

The stability of species populations largely depends on sexual structure , i.e. ratios of individuals of different sexes. Sexual groups within populations are formed on the basis of differences in morphology (shape and structure of the body) and ecology of the different sexes.

For example, in some insects, males have wings, but females do not, males of some mammals have horns, but females do not, male birds have bright plumage, while females have camouflage.

Ecological differences are reflected in food preferences (females of many mosquitoes suck blood, while males feed on nectar).

The genetic mechanism ensures an approximately equal ratio of individuals of both sexes at birth. However, the initial ratio is soon disrupted as a result of physiological, behavioral and environmental differences between males and females, causing uneven mortality.

Analysis of the age and sex structure of populations makes it possible to predict its numbers for a number of coming generations and years. This is important when assessing the possibilities of fishing, shooting animals, saving crops from locust attacks, and in other cases.

Hot springs, usually found in volcanic areas, have a fairly rich living population.

Long ago, when bacteria and other lower creatures had the most superficial understanding, the existence of a unique flora and fauna in the baths was established. For example, in 1774, Sonnerath reported the presence of fish in the hot springs of Iceland, which had a temperature of 69°. This conclusion was not later confirmed by other researchers in relation to the baths of Iceland, but similar observations were made in other places. On the island of Ischia, Ehrenberg (1858) noted the presence of fish in springs with temperatures above 55°. Hoppe-Seyler (1875) also saw fish in water with a temperature also of about 55°. Even if we assume that in all the noted cases thermometry was carried out inaccurately, it is still possible to draw a conclusion about the ability of some fish to live at fairly elevated temperatures. Along with fish, the presence of frogs, worms and mollusks was sometimes noted in the thermal baths. At a later time, simple animals were also discovered here.

In 1908, the work of Issel was published, who established in more detail the temperature limits for the animal world living in hot springs.

Along with the animal world, the presence of algae in thermal baths is extremely easily established, sometimes forming powerful foulings. According to Rodina (1945), the thickness of algae accumulated in hot springs often reaches several meters.

We have talked enough about associations of thermophilic algae and the factors that determine their composition in the section “Algae living at high temperatures.” Here we just recall that the most heat-resistant of them are blue-green algae, which can develop up to a temperature of 80-85°. Green algae tolerate temperatures slightly above 60°, and diatoms stop developing at approximately 50°.

As already noted, algae that develop in thermal baths play a significant role in the formation of various types of scales, which include mineral compounds.

Thermophilic algae have a great influence on the development of the bacterial population in thermal baths. During their lifetime, through exosmosis, they release a certain amount of organic compounds into the water, and when they die, they even create a fairly favorable substrate for bacteria. It is not surprising, therefore, that the bacterial population of thermal waters is most richly represented in places where algae accumulate.

Moving on to the thermophilic bacteria of hot springs, we must point out that in our country they have been studied by many microbiologists. The names of Tsiklinskaya (1899), Gubin (1924-1929), Afanasyeva-Kester (1929), Egorova (1936-1940), Volkova (1939), Rodina (1945) and Isachenko (1948) should be noted here.

Most researchers who dealt with hot springs limited themselves to the fact of establishing bacterial flora in them. Only relatively few microbiologists dwelled on the fundamental aspects of the life of bacteria in thermal baths.

In our review we will focus only on the studies of the last group.

Thermophilic bacteria were found in hot springs in a number of countries - the Soviet Union, France, Italy, Germany, Slovakia, Japan, etc. Since the waters of hot springs are often poor in organic substances, it is not surprising that they sometimes contain very small amounts of saprophytic bacteria.

The reproduction of autotrophically feeding bacteria, among which iron and sulfur bacteria are quite widespread in thermal baths, is determined mainly by the chemical composition of the water, as well as its temperature.

Some thermophilic bacteria isolated from hot waters have been described as new species. Similar forms include: Bac. thermophilus filiformis. studied by Tsiklinskaya (1899), two spore-bearing rods - Bac. ludwigi and Bac. ilidzensis capsulatus isolated by Karlinsky (1895), Spirochaeta daxensis isolated by Cantacuzene (1910), and Thiospirillum pistiense isolated by Churda (1935).

The water temperature of hot springs greatly affects the species composition of the bacterial population. In waters with a lower temperature, cocci and spirochaete-like bacteria were found (works by Rodina, Kantakouzena). However, here too the predominant form is spore-bearing rods.

Recently, the influence of temperature on the species composition of the bacterial population of thermal baths was very colorfully shown in the work of Rodina (1945), who studied the hot springs of Khoja-Obi-Garm in Tajikistan. The temperature of individual sources of this system ranges from 50-86°. When combined, these thermal baths give rise to a stream, at the bottom of which, in places with temperatures not exceeding 68°, rapid growth of blue-green algae was observed. In some places, the algae formed thick layers of different colors. At the water's edge, there were sulfur deposits on the side walls of the niches.

In different sources, in the runoff, as well as in the thickness of blue-green algae, fouling glasses were placed for three days. In addition, the collected material was sown on nutrient media. It was found that water with the highest temperature has predominantly rod-shaped bacteria. Wedge-shaped forms, in particular those resembling Azotobacter, occur at temperatures not exceeding 60°. Judging by all the data, we can say that Azotobacter itself does not grow above 52°, and the large round cells found in fouling belong to other types of microbes.

The most heat-resistant are some forms of bacteria that develop on meat-peptone agar, thiobacteria such as Tkiobacillus thioparus and desulfurizers. By the way, it is worth mentioning that Egorova and Sokolova (1940) found Microspira in water that had a temperature of 50-60°.

In Rodina's work, nitrogen-fixing bacteria were not detected in water at 50°C. However, when studying soils, anaerobic nitrogen fixers were found at 77°C, and Azotobacter at 52°C. This leads us to believe that water is generally not a suitable substrate for nitrogen fixers.

A study of bacteria in the soils of hot springs revealed the same dependence of group composition on temperature there as in water. However, the soil micropopulation was much richer in numbers. Sandy soils, poor in organic compounds, had a rather sparse micropopulation, while those containing dark-colored organic matter were abundantly populated by bacteria. Thus, the connection between the composition of the substrate and the nature of the microscopic creatures contained in it was revealed extremely clearly.

It is noteworthy that thermophilic bacteria that decompose fiber were not found either in the water or in the mud of Rodina. We are inclined to explain this point by methodological difficulties, since thermophilic cellulose-decomposing bacteria are quite demanding on nutrient media. As Imshenetsky showed, their isolation requires quite specific nutrient substrates.

In hot springs, in addition to saprophytes, there are autotrophs - sulfur and iron bacteria.

The oldest observations about the possibility of growth of sulfur bacteria in thermal baths were apparently made by Meyer and Ahrens, as well as Miyoshi. Miyoshi observed the development of filamentous sulfur bacteria in springs whose water temperature reached 70°. Egorova (1936), who studied the Bragun sulfur springs, noted the presence of sulfur bacteria even at a water temperature of 80°.

In the chapter “General characteristics of the morphological and physiological characteristics of thermophilic bacteria,” we described in sufficient detail the properties of thermophilic iron and sulfur bacteria. It is not advisable to repeat this information, and we will limit ourselves here to only reminding that individual genera and even species of autotrophic bacteria complete their development at different temperatures.

The maximum temperature, therefore, for sulfur bacteria is recorded at about 80°. For iron bacteria such as Streptothrix ochraceae and Spirillum ferrugineum, Miyoshi set a maximum of 41-45°.

Dufrenois (Dufrencfy, 1921) found iron bacteria very similar to Siderocapsa on sediments in hot waters with a temperature of 50-63°. According to his observations, the growth of filamentous iron bacteria occurred only in cold waters.

Volkova (1945) observed the development of bacteria from the genus Gallionella in the mineral springs of the Pyatigorsk group when the water temperature did not exceed 27-32°. In thermal baths with higher temperatures, iron bacteria were completely absent.

Comparing the materials we have noted, one involuntarily has to conclude that in some cases it is not the temperature of the water, but its chemical composition that determines the development of certain microorganisms.

Bacteria, along with algae, take an active part in the formation of some biolite and caustobiolite minerals. The role of bacteria in calcium precipitation has been studied in more detail. This issue is covered in detail in the section on physiological processes caused by thermophilic bacteria.

The conclusion made by Volkova deserves attention. She notes that the “barezhina”, deposited in a thick cover in the streams of the sources of the sulfur springs of Pyatigorsk, contains a lot of elemental sulfur and is based on the mycelium of a mold fungus from the genus Penicillium. The mycelium makes up the stroma, which includes rod-shaped bacteria, apparently related to sulfur bacteria.

Brussoff believes that thermal bacteria also take part in the formation of silicic acid deposits.

Bacteria that reduce sulfates were found in the thermal baths. According to Afanasyeva-Kester, they resemble Microspira aestuarii van Delden and Vibrio thermodesulfuricans Elion. A number of thoughts about the possible role of these bacteria in the formation of hydrogen sulfide in thermal baths were expressed by Gubin (1924-1929).

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Bacteria are the oldest known group of organisms
Layered stone structures - stromatolites - dated in some cases to the beginning of the Archeozoic (Archean), i.e. arose 3.5 billion years ago, is the result of the vital activity of bacteria, usually photosynthesizing, the so-called. blue-green algae. Similar structures (bacterial films impregnated with carbonates) are still formed today, mainly off the coast of Australia, the Bahamas, in the California and Persian Gulfs, but they are relatively rare and do not reach large sizes, because herbivorous organisms, such as gastropods, feed on them. The first nucleated cells evolved from bacteria approximately 1.4 billion years ago.

The archaeobacteria thermoacidophiles are considered to be the most ancient of existing living organisms. They live in hot spring water that is highly acidic. At temperatures below 55oC (131oF) they die!

90% of the biomass in the seas turns out to be microbes.

Life appeared on Earth
3.416 billion years ago, that is, 16 million years earlier than is generally believed in the scientific world. Analyzes of one of the corals, whose age exceeds 3.416 billion years, have proven that at the time of the formation of this coral, life at the microbial level already existed on Earth.

Oldest microfossil
Kakabekia barghoorniana (1964-1986) was found at Harich, Goonedd, Wales, with an estimated age of over 4,000,000,000 years.
The most ancient form of life
Fossilized imprints of microscopic cells have been discovered in Greenland. It turned out that their age is 3800 million years, which makes them the most ancient life forms known to us.

Bacteria and eukaryotes
Life can exist in the form of bacteria - the simplest organisms that do not have a nucleus in the cell, the oldest (archaea), almost as simple as bacteria, but distinguished by an unusual membrane; eukaryotes are considered its top - in fact, all other organisms whose genetic code is stored in cell nucleus.

The oldest inhabitants of the Earth were found in the Mariana Trench
At the bottom of the world's deepest Mariana Trench in the center of the Pacific Ocean, 13 species of single-celled organisms unknown to science have been discovered, existing unchanged for almost a billion years. Microorganisms were found in soil samples taken in the Challenger Fault in the fall of 2002 by the Japanese automatic bathyscaphe "Kaiko" at a depth of 10,900 meters. In 10 cubic centimeters of soil, 449 previously unknown primitive unicellular round or elongated 0.5 - 0.7 mm in size were discovered. After several years of research, they were divided into 13 species. All these organisms almost completely correspond to the so-called. "unknown biological fossils" that were discovered in the 1980s in Russia, Sweden and Austria in soil layers dating back 540 million to a billion years.

Based on genetic analysis, Japanese researchers claim that single-celled organisms found at the bottom of the Mariana Trench have existed unchanged for more than 800 million, or even a billion, years. Apparently, these are the most ancient of all currently known inhabitants of the Earth. For the sake of survival, single-celled organisms from the Challenger fault were forced to go to extreme depths, since in the shallow layers of the ocean they could not compete with younger and more aggressive organisms.

The first bacteria appeared in the Archaeozoic era
The development of the Earth is divided into five periods of time called eras. The first two eras, Archeozoic and Proterozoic, lasted 4 billion years, that is, almost 80% of all earth history. During the Archeozoic, the formation of the Earth occurred, water and oxygen appeared. About 3.5 billion years ago, the first tiny bacteria and algae appeared. During the Proterozoic era, about 700 years ago, the first animals appeared in the sea. These were primitive invertebrate creatures, such as worms and jellyfish. The Paleozoic era began 590 million years ago and lasted 342 million years. Then the Earth was covered with swamps. During the Paleozoic, large plants, fish and amphibians appeared. The Mesozoic era began 248 million years ago and lasted 183 million years. At this time, the Earth was inhabited by huge dinosaur lizards. The first mammals and birds also appeared. The Cenozoic era began 65 million years ago and continues to this day. At this time, the plants and animals that surround us today arose.

Where do bacteria live
Bacteria are abundant in soil, at the bottom of lakes and oceans—anywhere organic matter accumulates. They live in the cold, when the thermometer is just above zero, and in hot acidic springs with temperatures above 90 C. Some bacteria tolerate very high salinity; in particular, they are the only organisms found in the Dead Sea. In the atmosphere, they are present in water droplets, and their abundance there usually correlates with the dustiness of the air. Thus, in cities, rainwater contains much more bacteria than in rural areas. There are few of them in the cold air of high mountains and polar regions, however, they are found even in the lower layer of the stratosphere at an altitude of 8 km.

Bacteria are involved in digestion
The digestive tract of animals is densely populated with bacteria (usually harmless). They are not necessary for the life of most species, although they can synthesize some vitamins. However, in ruminants (cows, antelopes, sheep) and many termites, they are involved in the digestion of plant food. Additionally, the immune system of an animal raised under sterile conditions does not develop normally due to lack of bacterial stimulation. The normal bacterial “flora” of the intestines is also important for suppressing harmful microorganisms that enter there.

A quarter of a million bacteria fit in a spot
Bacteria are much smaller than the cells of multicellular plants and animals. Their thickness is usually 0.5–2.0 µm, and their length is 1.0–8.0 µm. Some forms are barely visible at the resolution of standard light microscopes (approximately 0.3 microns), but species are also known with a length of more than 10 microns and a width that also goes beyond the specified limits, and a number of very thin bacteria can exceed 50 microns in length. On the surface corresponding to the point marked with a pencil, a quarter of a million medium-sized bacteria will fit.

Bacteria offer lessons in self-organization
In bacterial colonies called stromatolites, the bacteria self-organize and form a huge working group, although none of them leads the others. This association is very stable and quickly recovers when damaged or changes in the environment. Also interesting is the fact that the bacteria in the stromatolite have different roles depending on where they are in the colony, and they all share genetic information. All these properties can be useful for future communication networks.

Abilities of bacteria
Many bacteria have chemical receptors that detect changes in the acidity of the environment and the concentration of sugars, amino acids, oxygen and carbon dioxide. Many motile bacteria also respond to temperature fluctuations, and photosynthetic species respond to changes in light intensity. Some bacteria perceive the direction of magnetic field lines, including the Earth's magnetic field, with the help of particles of magnetite (magnetic iron ore - Fe3O4) present in their cells. In water, bacteria use this ability to swim along lines of force in search of a favorable environment.

Memory of bacteria
Conditioned reflexes in bacteria are unknown, but they do have a certain kind of primitive memory. While swimming, they compare the perceived intensity of the stimulus with its previous value, i.e. determine whether it has become larger or smaller, and, based on this, maintain the direction of movement or change it.

Bacteria double in number every 20 minutes
Partly due to the small size of bacteria, their metabolic rate is very high. Under the most favorable conditions, some bacteria can double their total mass and number approximately every 20 minutes. This is explained by the fact that a number of their most important enzyme systems function at a very high speed. Thus, a rabbit needs a few minutes to synthesize a protein molecule, while bacteria take seconds. However, in a natural environment, for example in soil, most bacteria are “on a starvation diet”, so if their cells divide, it is not every 20 minutes, but once every few days.

Within 24 hours, 1 bacterium could produce 13 trillion others.
One E. coli bacterium (Esherichia coli) could produce offspring within 24 hours, the total volume of which would be enough to build a pyramid with an area of ​​2 sq. km and a height of 1 km. Under favorable conditions, in 48 hours one cholera vibrio (Vibrio cholerae) would give birth to offspring weighing 22 * ​​1024 tons, which is 4 thousand times the mass of the globe. Fortunately, only a small number of bacteria survive.

How many bacteria are there in the soil?
The top layer of soil contains from 100,000 to 1 billion bacteria per 1 g, i.e. approximately 2 tons per hectare. Typically, all organic residues, once in the ground, are quickly oxidized by bacteria and fungi.

Bacteria eat pesticides
Genetically modified ordinary E. coli is capable of eating organophosphorus compounds - toxic substances that are toxic not only to insects, but also to humans. The class of organophosphorus compounds includes some types of chemical weapons, for example, sarin gas, which has a nerve-paralytic effect.

A special enzyme, a type of hydrolase, originally found in some “wild” soil bacteria, helps the modified E. coli deal with organophosphates. After testing many genetically similar varieties of bacteria, the scientists chose a strain that kills the pesticide methyl parathion 25 times more efficiently than the original soil bacteria. To prevent the toxin eaters from “running away”, they were secured on a cellulose matrix - it is unknown how the transgenic E. coli will behave once free.

Bacteria will happily eat plastic with sugar
Polyethylene, polystyrene and polypropylene, which make up a fifth of urban waste, have become attractive to soil bacteria. When polystyrene styrene units are mixed with a small amount of another substance, “hooks” are formed on which particles of sucrose or glucose can get caught. Sugars “hang” on styrene chains like pendants, making up only 3% of the total weight of the resulting polymer. But Pseudomonas and Bacillus bacteria notice the presence of sugars and, eating them, destroy the polymer chains. As a result, the plastics begin to decompose within a few days. The final products of processing are carbon dioxide and water, but on the way to them organic acids and aldehydes appear.

Succinic acid from bacteria
A new species of bacteria that produces succinic acid has been discovered in the rumen, a section of the digestive tract of ruminants. Microbes live and reproduce well without oxygen, in an atmosphere of carbon dioxide. In addition to succinic acid, they produce acetic and formic acid. The main nutritional resource for them is glucose; from 20 grams of glucose, bacteria create almost 14 grams of succinic acid.

Deep Sea Bacteria Cream
Bacteria collected from a hydrothermal fissure two kilometers deep in California's Pacific Bay will help create a lotion that effectively protects the skin from the sun's harmful rays. Among the microbes that live here at high temperatures and pressures is Thermus thermophilus. Their colonies thrive at temperatures of 75 degrees Celsius. Scientists are going to use the fermentation process of these bacteria. The result will be a “cocktail of proteins,” including enzymes that are especially eager to destroy highly active chemical compounds formed by exposure to ultraviolet rays and involved in reactions that destroy skin. According to the developers, the new components can destroy hydrogen peroxide three times faster at 40 degrees Celsius than at 25.

Humans are hybrids of Homo sapiens and bacteria
A person is a collection, in fact, of human cells, as well as bacterial, fungal and viral forms of life, the British say, and the human genome does not predominate in this conglomerate. In the human body there are several trillion cells and more than 100 trillion bacteria, five hundred species, by the way. In terms of the amount of DNA in our bodies, it is bacteria, not human cells, that lead. This biological cohabitation is beneficial to both parties.

Bacteria accumulate uranium
One strain of the Pseudomonas bacterium is able to effectively capture uranium and other heavy metals from the environment. Researchers isolated this type of bacteria from wastewater from a Tehran metallurgical plant. The success of cleaning work depends on temperature, acidity of the environment and the content of heavy metals. The best results were at 30 degrees Celsius in a slightly acidic environment with a uranium concentration of 0.2 grams per liter. Its granules accumulate in the walls of bacteria, reaching 174 mg per gram of dry weight of bacteria. In addition, the bacterium captures copper, lead and cadmium and other heavy metals from the environment. The discovery can serve as the basis for the development of new methods for treating wastewater from heavy metals.

Two species of bacteria unknown to science were found in Antarctica
The new microorganisms Sejongia jeonnii and Sejongia antarctica are gram-negative bacteria containing a yellow pigment.

So many bacteria on the skin!
The skin of mole rats has up to 516,000 bacteria per square inch; dry areas of the same animal's skin, such as the front paws, have only 13,000 bacteria per square inch.

Bacteria against ionizing radiation
The microorganism Deinococcus radiodurans is capable of withstanding 1.5 million rads. ionizing radiation exceeding lethal levels for other life forms by more than 1000 times. While the DNA of other organisms will be destroyed and destroyed, the genome of this microorganism will not be damaged. The secret of such stability lies in the specific shape of the genome, which resembles a circle. It is this fact that contributes to such resistance to radiation.

Microorganisms against termites
The termite control drug "Formosan" (USA) uses the natural enemies of termites - several types of bacteria and fungi that infect and kill them. After an insect is infected, fungi and bacteria settle in its body, forming colonies. When an insect dies, its remains become a source of spores that infect their fellow insects. Microorganisms were selected that reproduce relatively slowly - the infected insect should have time to return to the nest, where the infection will be transmitted to all members of the colony.

Microorganisms live at the pole
Colonies of microbes have been found on rocks near the north and south poles. These places are not very suitable for life - the combination of extremely low temperatures, strong winds and harsh ultraviolet radiation looks frightening. But 95 percent of the rocky plains studied by scientists are inhabited by microorganisms!

These microorganisms get enough of the light that gets under the stones through the cracks between them, reflecting from the surfaces of neighboring stones. Due to temperature changes (stones are heated by the sun and cooled when there is no sun), movements occur in the stone placers, some stones find themselves in complete darkness, while others, on the contrary, are exposed to light. After such movements, microorganisms “migrate” from darkened stones to illuminated ones.

Bacteria live in slag dumps
The most alkaline-loving organisms on the planet live in polluted water in the United States. Scientists have discovered microbial communities thriving in cinder dumps in the Calume Lake area in southwest Chicago, where the water's acidity (pH) level is 12.8. Living in such an environment is comparable to living in caustic soda or floor cleaning liquid. In such dumps, air and water react with slag, which produces calcium hydroxide (caustic soda), which increases the pH. The bacteria were discovered during a study of contaminated groundwater accumulated from more than a century of industrial iron dumps coming from Indiana and Illinois.

Genetic analysis has shown that some of these bacteria are close relatives of Clostridium and Bacillus species. These species have previously been found in the acidic waters of Mono Lake in California, tuff pillars in Greenland and the cement-polluted waters of a deep gold mine in Africa. Some of these organisms use hydrogen released when metallic iron slags corrode. How exactly the unusual bacteria got into the slag dumps remains a mystery. It is possible that local bacteria have adapted to their extreme habitat over the last century.

Microbes determine water pollution
Modified E. coli bacteria are grown in a medium containing contaminants and their amounts are determined at different points in time. Bacteria have a built-in gene that allows cells to glow in the dark. By the brightness of the glow one can judge their number. Bacteria are frozen in polyvinyl alcohol, then they can withstand low temperatures without serious damage. They are then thawed, grown in suspension and used in research. In a polluted environment, cells grow worse and die more often. The number of dead cells depends on time and degree of contamination. These indicators differ for heavy metals and organic substances. For any substance, the rate of death and the dependence of the number of dead bacteria on the dose are different.

Viruses have
...a complex structure of organic molecules, what is even more important is the presence of its own viral genetic code and the ability to reproduce.

Origin of viruses
It is generally accepted that viruses originated as a result of the isolation (autonomization) of individual genetic elements of the cell, which, in addition, received the ability to be transmitted from organism to organism. The size of viruses varies from 20 to 300 nm (1 nm = 10–9 m). Almost all viruses are smaller in size than bacteria. However, the largest viruses, such as cowpox virus, are the same size as the smallest bacteria (chlamydia and rickettsia.

Viruses are a form of transition from just chemistry to life on Earth
There is a version that viruses arose a long time ago - thanks to intracellular complexes that gained freedom. Inside a normal cell, there is a movement of many different genetic structures (messenger RNA, etc., etc....), which can be the progenitors of viruses. But perhaps everything was quite the opposite - and viruses are the oldest form of life, or rather a transitional stage from “just chemistry” to life on Earth.
Some scientists even associate the origin of eukaryotes themselves (and, therefore, of all single- and multicellular organisms, including you and me) with viruses. It is possible that we emerged as a result of the “collaboration” of viruses and bacteria. The former provided genetic material, and the latter provided ribosomes - protein intracellular factories.

Viruses are not capable
... to reproduce on their own - the internal mechanisms of the cell that the virus infects do this for them. The virus itself also cannot work with its genes - it is not able to synthesize proteins, although it has a protein shell. It simply steals ready-made proteins from cells. Some viruses even contain carbohydrates and fats - but again, stolen ones. Outside the victim cell, the virus is simply a gigantic accumulation of albeit very complex molecules, but without metabolism or any other active actions.

Surprisingly, the simplest creatures on the planet (we will still call viruses creatures) are one of the biggest mysteries of science.

The largest virus Mimi, or Mimivirus
...(causing an outbreak of influenza) is 3 times more than other viruses, and 40 times more than others. It carries 1260 genes (1.2 million “letter” bases, which is more than other bacteria), while known viruses have only three to a hundred genes. Moreover, the genetic code of the virus consists of DNA and RNA, while all known viruses use only one of these “tablets of life,” but never both together. 50 Mimi genes are responsible for things that have never been seen in viruses before. In particular, Mimi is capable of independently synthesizing 150 types of proteins and even repairing its own damaged DNA, which is generally nonsense for viruses.

Changes in the genetic code of viruses can make them deadly
American scientists experimented with the modern influenza virus - an unpleasant and severe, but not very lethal disease - by crossing it with the virus of the infamous "Spanish flu" of 1918. The modified virus killed mice outright with symptoms characteristic of the Spanish flu (acute pneumonia and internal bleeding). However, its differences from the modern virus at the genetic level turned out to be minimal.

The Spanish flu epidemic of 1918 killed more people than during the worst medieval epidemics of plague and cholera, and even more than front-line losses in the First World War. Scientists suggest that the Spanish flu virus could have arisen from the so-called “bird flu” virus, combining with a regular virus, for example, in the body of pigs. If bird flu successfully crosses with human flu and is able to pass from person to person, then we get a disease that can cause a global pandemic and kill several million people.

The most powerful poison
...now considered a bacillus D toxin. 20 mg is enough to poison the entire population of the Earth.

Viruses can swim
Eight types of phage viruses live in the Ladoga waters, differing in shape, size and length of legs. Their number is significantly higher than that typical for fresh water: from two to twelve billion particles per liter of sample. In some samples there were only three types of phages; their highest content and diversity were in the central part of the reservoir, all eight types. Usually the opposite is true: there are more microorganisms in the coastal areas of lakes.

Silence of viruses
Many viruses, such as herpes, have two phases in their development. The first occurs immediately after infection of a new host and does not last long. Then the virus “falls silent” and quietly accumulates in the body. The second can begin in a few days, weeks or years, when the virus, “silent” for the time being, begins to multiply like an avalanche and causes disease. The presence of a “latent” phase protects the virus from dying out when the host population quickly becomes immune to it. The more unpredictable the external environment from the point of view of the virus, the more important it is for it to have a period of “silence”.

Viruses play an important role
Viruses play an important role in the life of any body of water. Their numbers reach several billion particles per liter of seawater in polar, temperate and tropical latitudes. In freshwater lakes, the virus content is usually lower by a factor of 100. Why there are so many viruses in Ladoga and they are so unusually distributed remains to be seen. But researchers have no doubt that microorganisms have a significant impact on the ecological state of natural water.

An ordinary amoeba has a positive reaction to a source of mechanical vibrations
Amoeba proteus is a freshwater amoeba about 0.25 mm long, one of the most common species of the group. It is often used in school experiments and laboratory research. The common amoeba is found in the sludge at the bottom of ponds with polluted water. It looks like a small, colorless gelatinous lump, barely visible to the naked eye.

In the common amoeba (Amoeba proteus), so-called vibrotaxis was discovered in the form of a positive reaction to a source of mechanical vibrations with a frequency of 50 Hz. This becomes understandable if we consider that in some species of ciliates that serve as amoeba food, the frequency of the beating of the cilia fluctuates just between 40 and 60 Hz. Amoeba also exhibits negative phototaxis. This phenomenon is that the animal tries to move from the illuminated area to the shadow. Thermotaxis of the amoeba is also negative: it moves from a warmer to a less heated part of the body of water. It is interesting to observe the galvanotaxis of amoeba. If a weak electric current is passed through water, the amoeba releases pseudopods only on the side facing the negative pole - the cathode.

The largest amoeba
One of the largest amoebas is the freshwater species Pelomyxa (Chaos) carolinensis, 2–5 mm long.

Amoeba moves
The cytoplasm of a cell is in constant motion. If the current of cytoplasm rushes to one point on the surface of the amoeba, a protrusion appears in this place on its body. It enlarges, becomes an outgrowth of the body - a pseudopod, cytoplasm flows into it, and the amoeba moves in this way.

Midwife for amoeba
An amoeba is a very simple organism, consisting of a single cell that reproduces by simple division. First, the amoeba cell doubles its genetic material, creating a second nucleus, and then changes shape, forming a constriction in the middle, which gradually divides it into two daughter cells. There remains a thin ligament between them, which they pull in different directions. Eventually the ligament breaks and the daughter cells begin independent life.

But in some species of amoeba, the reproduction process is not at all so simple. Their daughter cells cannot independently break the ligament and sometimes merge again into one cell with two nuclei. Dividing amoebas cry out for help by releasing a special chemical to which the “midwife amoeba” reacts. Scientists believe that, most likely, this is a complex of substances, including fragments of proteins, lipids and sugars. Apparently, when an amoeba cell divides, its membrane experiences tension, which causes the release of a chemical signal into the external environment. Then the dividing amoeba is helped by another, which comes in response to a special chemical signal. It inserts itself between dividing cells and puts pressure on the ligament until it ruptures.

Living fossils
The most ancient of them are radiolarians, single-celled organisms covered with a shell-like growth mixed with silica, the remains of which were discovered in Precambrian deposits, whose age ranges from one to two billion years.

The most enduring
The tardigrade, an animal measuring less than half a millimeter in length, is considered the hardiest life form on Earth. This animal can withstand temperatures ranging from 270 degrees Celsius to 151 degrees Celsius, exposure to X-rays, vacuum conditions and pressure six times that of the deepest ocean floor. Tardigrades can live in gutters and cracks in masonry. Some of these little creatures came to life after a hundred years of hibernation in the dry moss of museum collections.

Acantharia, the simplest organisms belonging to radiolarians, reach a length of 0.3 mm. Their skeleton consists of strontium sulfate.

The total mass of phytoplankton is only 1.5 billion tons, while the mass of zoopalnkton is 20 billion tons.

The speed of movement of the ciliate-slipper (Paramecium caudatum) is 2 mm per second. This means that the shoe swims in a second a distance 10-15 times greater than the length of its body. There are 12 thousand cilia on the surface of the ciliate slipper.

Green Euglena (Euglena viridis) can serve as a good indicator of the degree of biological treatment of water. With a decrease in bacterial contamination, its number increases sharply.

What were the earliest forms of life on Earth?
Creatures that are neither plants nor animals are called rangeomorphs. They first settled on the ocean floor about 575 million years ago, after the last global glaciation (this time is called the Ediacaran period), and were among the first soft-bodied creatures. This group existed until 542 million years ago, when rapidly proliferating modern animals displaced most of these species.

Organisms assembled into fractal patterns of branching parts. They were unable to move and did not have reproductive organs, but multiplied, apparently creating new branches. Each branching element consisted of many tubes held together by a semi-rigid organic skeleton. Scientists discovered rangeomorphs assembled into several different forms, which he believes collected food in different layers of the water column. The fractal pattern seems quite complex, but, according to the researcher, the similarity of the organisms to each other made a simple genome sufficient to create new free-floating branches and to connect the branches into more complex structures.

The fractal organism, found in Newfoundland, was 1.5 centimeters wide and 2.5 centimeters long.
Such organisms accounted for up to 80% of all living in the Ediacara when there were no mobile animals. However, with the advent of more mobile organisms, their decline began, and as a result they were completely replaced.

Immortal life exists deep beneath the ocean floor
Under the surface of the bottom of the seas and oceans there is an entire biosphere. It turns out that at depths of 400-800 meters below the bottom, in the thickness of ancient sediments and rocks, myriads of bacteria live. Some specific specimens are estimated to be 16 million years old. They are practically immortal, scientists say.

Researchers believe that it was in such conditions, in the depths of bottom rocks, that life arose more than 3.8 billion years ago and only later, when the environment on the surface became suitable for habitation, did it master the ocean and land. Scientists have long found traces of life (fossils) in bottom rocks taken from very great depths under the surface of the bottom. They collected a lot of samples in which they found living microorganisms. Including in rocks raised from depths of more than 800 meters below the ocean floor. Some sediment samples were many millions of years old, which meant that, for example, a bacterium trapped in such a sample was the same age. About a third of the bacteria that scientists have discovered in deep bottom rocks are alive. In the absence of sunlight, the source of energy for these creatures is various geochemical processes.

The bacterial biosphere located under the seabed is very large and outnumbers all bacteria living on land. Therefore, it has a noticeable effect on geological processes, the balance of carbon dioxide, and so on. Perhaps, the researchers suggest, without such underground bacteria we would not have oil and gas.

In boiling water at a temperature of 100°C, all forms of living organisms die, including bacteria and microbes, which are known for their persistence and vitality - this is a widely known and generally accepted fact. But it turns out to be wrong!

In the late 1970s, with the advent of the first deep-sea vehicles, hydrothermal vents, from which streams of extremely hot, highly mineralized water continuously flowed. The temperature of such streams reaches an incredible 200-400°C. At first, no one could have imagined that life could exist at a depth of several thousand meters from the surface, in eternal darkness, and even at such a temperature. But she existed there. And not primitive single-celled life, but entire independent ecosystems consisting of species previously unknown to science.

A hydrothermal vent found at the bottom of the Cayman Trench at a depth of about 5,000 meters. Such springs are called black smokers due to the eruption of black, smoke-like water.

The basis of ecosystems living near hydrothermal vents are chemosynthetic bacteria - microorganisms that obtain the necessary nutrients by oxidizing various chemical elements; in a particular case by oxidation of carbon dioxide. All other representatives of thermal ecosystems, including filter-feeding crabs, shrimp, various mollusks and even huge marine worms, depend on these bacteria.

This black smoker is completely enveloped in white sea anemones. Conditions that mean death for other marine organisms are the norm for these creatures. White anemones obtain their nutrition by ingesting chemosynthetic bacteria.

Organisms that live in black smokers"are completely dependent on local conditions and are not able to survive in the habitat familiar to the vast majority of marine inhabitants. For this reason, for a long time not a single creature could be brought to the surface alive; they all died when the water temperature dropped.

Pompeian worm (lat. Alvinella pompejana) - this inhabitant of underwater hydrothermal ecosystems received a rather symbolic name.

The ISIS underwater unmanned vehicle under the control of British oceanologists managed to lift the first living creature. Scientists have found that temperatures below 70°C are deadly for these amazing creatures. This is quite remarkable, since a temperature of 70°C is lethal for 99% of organisms living on Earth.

The discovery of underwater thermal ecosystems was extremely important for science. First, the limits within which life can exist have been expanded. Secondly, the discovery led scientists to a new version of the origin of life on Earth, according to which life originated in hydrothermal vents. And thirdly, this discovery once again made us understand that we know negligibly little about the world around us.