Circulation and biogeochemical cycles of substances. Biological and geological cycles
The cycle of substances in nature is the most important ecological concept.
On fig. the biological cycle is presented in combination with a simplified diagram of the energy flow. Substances are involved in the circulation, and the energy flow is unidirectional from plants that convert the energy of the sun into the energy of chemical bonds, to animals that use this energy, and further to microorganisms that destroy organic substances.
A unidirectional flow of energy sets in motion the circulation of substances. Each chemical element, making a cycle in an ecosystem, alternately passes from an organic form to an inorganic one and vice versa.
Rice. 1. Energy flow and circulation of biogenic elements in the biosphere
Photosynthesis- creation organic matter(glucose, starch, cellulose, etc.) from carbon dioxide and water with the participation of chlorophyll under the action of solar energy:
6CO 2 + 12H 2 O + hν (673 kcal) \u003d C 6 H 12 O 6 + 6O 2 + 6H 2 O
Photosynthesis is the process of capturing solar energy by photosynthetic organisms and converting it into biomass energy.
Every year, the plant world stores free energy 10 times higher than the amount of mineral energy consumed per year by the entire population of the Earth. These minerals themselves (coal, oil and natural gas) are also products of photosynthesis that took place millions of years ago.
Every year, photosynthesis absorbs 200 billion tons of carbon dioxide and releases up to 320 billion tons of oxygen. All carbon dioxide of the atmosphere passes through living matter in 6-7 years.
Processes of destruction of organic matter to the simplest molecules also take place in the biosphere: CO 2 , H 2 O, NH 3 . The decomposition of organic compounds occurs in animal organisms, in plants during respiration with the formation of CO 2 and H 2 O.
The mineralization of organic substances, the decomposition of dead organic matter to simple inorganic compounds, occurs under the action of microorganisms.
Opposite processes of formation and destruction of organic matter in the biosphere form a single biological cycle of atoms. In the process of mineralization of organic compounds, the energy that was absorbed during photosynthesis is released. It is released as heat and also as chemical energy.
Biological cycleis a set of processes for the entry of chemical elements into living organisms, the biosynthesis of new complex compounds and the return of elements to the soil, atmosphere and hydrosphere.
The intensity of the biological cycle (BIC) is determined by the ambient temperature and the amount of water. The biological cycle proceeds more intensively in tropical rainforests than in the tundra.
The most important result of the biological cycle of substances is the formation of a humus soil horizon on land.
The biological cycle is characterized by the following indicators.
Biomass - the mass of living matter accumulated by a given point in time (phyto-, zoo-, microbiomass).
plant biomass(phytomass) - the mass of living and dead plant organisms.
Fall - the amount of organic matter of plants that have died off per unit area per unit of time.
Growth- biomass accumulated per unit area per unit of time.
The chemical composition of plants depends on two main factors:
1) ecological, - the environment of plant growth, - the levels of the content of elements in the environment, the forms of presence, including mobile ones, available to plants;
2) genetic, in connection with the peculiarities of the origin of the plant species.
Under conditions of environmental pollution, the concentration of elements in plants is determined by the first factor. Both factors are important in background (undisturbed) landscapes.
Depending on the reaction to the chemical factor of the environment (to the content of chemical elements), 2 groups of plants can be distinguished:
1) adapted to changes in the concentration of chemical elements;
2) not adapted to changes in the concentration of chemical elements.
Changes in the concentrations of chemical elements in the environment in unadapted plants cause physiological disturbances leading to diseases; the development of plants is inhibited, the species dies out.
Some plant species are well adapted to tolerate high concentrations of elements. These are wild plants that grow for a long time in the area, which, as a result of natural selection, acquire resistance to adverse environmental conditions.
Plants that concentrate chemical elements are called concentrators. For example: sunflower, potatoes concentrate potassium, tea - aluminum, mosses - iron. Gold is accumulated by wormwood, horsetail, corn, and oak.
12.1. The concept of the biological cycle
The biological cycle is the cycle of chemical elements and substances that arose simultaneously with the appearance of life on Earth, carried out by the vital activity of organisms. It plays a special role in the biosphere. On this occasion, N. V. Timofeev-Resovsky wrote: “There is a huge, eternal, constantly working biological cycle in the biosphere, a number of substances, a number of forms of energy constantly circulate in this large cycle of the biosphere” (M. M. Kamshilov, 1974; V. A. Vronsky, 1997). The problem of the long existence and development of life is solved in the laws of the biological cycle. On a body of finite volume, which is the Earth, the reserves of available mineral elements necessary for the implementation of the function of life cannot be infinite. If they were only consumed, life would have to end sooner or later. “The only way to give a limited quantity the property of an infinite,” writes W. R. Williams, “is to make it rotate along a closed curve.” Life used exactly this method. “Green plants create organic matter, non-green plants destroy it. From mineral compounds obtained from the decay of organic matter, new green plants build new organic matter, and so on without end. With this in mind, each type of organism is a link in the biological cycle. Using the bodies or decay products of some organisms as a means of subsistence, he must give to the environment what others can use. The role of microorganisms is especially great. By mineralizing the organic remains of animals and plants, microorganisms turn them into a "single currency" - mineral salts and the simplest organic compounds such as biogenic stimulants, again used by green plants in the synthesis of new organic matter. One of the main paradoxes of life is that its continuity is ensured by the processes of decay, destruction. Complicated organic compounds, energy is released, the stock of information inherent in complexly organized living bodies is lost. As a result of the activity of destructors, mainly microorganisms, any form of life will inevitably be included in the biological cycle. Therefore, with their help, the natural self-regulation of the biosphere is carried out. Two properties allow microorganisms to play such important role: the ability to adapt relatively quickly to various conditions and the ability to use a wide variety of substrates as a source of carbon and energy. Higher organisms do not have such abilities. Therefore, they can exist only as a kind of superstructure on a solid foundation of microorganisms. The biological cycle, based on the interaction of synthesis and destruction of organic matter, is one of the most significant forms of life organization on a planetary scale. Only he ensures the continuity of life and its progressive development.
Individuals and species of organisms of different systematic groups interacting directly and indirectly with the help of numerous and multilateral direct and feedback links. The biological cycle of the planet also appears to be a complex system of private cycles - ecological systems interconnected various forms interactions.
The biological cycle is carried out mainly along trophic (food) chains (Figure 12.1).
With the important role of plants and animals in it, the flow of biogenic elements such as nitrogen, phosphorus, sulfur through populations of microorganisms in the cycle is approximately an order of magnitude higher than through populations of plants and animals. An important indicator of the intensity of the biological cycle is the rate of circulation of chemical elements. As an indicator of this intensity, one can use the rate of accumulation and decomposition of dead organic matter, which is formed as a result of the annual fall of leaves and the death of organisms.
The ratio, for example, of the weight of the litter to that part of the litter that forms the litter, serves as an indicator of the rate of decomposition of the litter and the release of chemical elements. The higher this index, the lower the intensity of the biological cycle in a given ecosystem. The largest value of the index (more than 50) is characterized by swampy forests and tundra. In dark coniferous forests, the index is 10-17, in broad-leaved forests - 3-4, in steppes - 1.0-1.5, in savannahs - no more than 0.2. In humid tropical forests, plant residues practically do not accumulate (index no more than 0.1). Therefore, here the biological cycle is the most intense.
All substances on the planet are in the process of circulation. Solar energy causes two cycles of matter on Earth: large (geological, biospheric) And small (biological).
The large circulation of substances in the biosphere is characterized by two important points: it is carried out throughout the entire geological development of the Earth and is a modern planetary process that takes a leading part in the further development of the biosphere.
The geological cycle is associated with the formation and destruction of rocks and the subsequent movement of destruction products - detrital material and chemical elements. A significant role in these processes was played and continues to be played by the thermal properties of the surface of land and water: the absorption and reflection of sunlight, thermal conductivity and heat capacity. The unstable hydrothermal regime of the Earth's surface, together with the planetary atmospheric circulation system, determined the geological circulation of substances, which at the initial stage of the Earth's development, along with endogenous processes, was associated with the formation of continents, oceans and modern geospheres. With the formation of the biosphere, the products of vital activity of organisms were included in the great cycle. The geological cycle supplies living organisms with nutrients and largely determines the conditions for their existence.
Main chemical elements lithospheres: oxygen, silicon, aluminum, iron, magnesium, sodium, potassium and others - participate in a large circulation, passing from the deep parts of the upper mantle to the surface of the lithosphere. The igneous rock that arose during the crystallization of magma, having arrived on the surface of the lithosphere from the depths of the Earth, undergoes decomposition and weathering in the biosphere. Weathering products pass into a mobile state, are carried away by waters, wind to low places of relief, fall into rivers, the ocean and form thick layers of sedimentary rocks, which over time, plunging to a depth in areas with elevated temperature and pressure, undergo metamorphosis, i.e. "remelted". During this remelting, a new metamorphic rock appears, entering the upper horizons earth's crust and re-entering the cycle of substances (rice.).
Easily mobile substances - gases and natural waters that make up the atmosphere and hydrosphere of the planet - undergo the most intensive and rapid circulation. The material of the lithosphere cycles much more slowly. In general, each cycle of any chemical element is part of the general big cycle substances on Earth, and all of them are closely related. The living matter of the biosphere in this circulation does a great job of redistributing the chemical elements that are constantly circulating in the biosphere, moving from external environment into organisms and back into the environment.
Small, or biological, circulation of substances- this
circulation of substances between plants, animals, fungi, microorganisms and soil. The essence of the biological cycle is the flow of two opposite, but interrelated processes - the creation of organic substances and their destruction. First stage The emergence of organic substances is due to the photosynthesis of green plants, i.e., the formation of living matter from carbon dioxide, water, and simple mineral compounds using solar energy. Plants (producers) extract molecules of sulfur, phosphorus, calcium, potassium, magnesium, manganese, silicon, aluminum, zinc, copper and other elements from the soil in a solution. Herbivorous animals (consumers of the first order) absorb compounds of these elements already in the form of food of plant origin. Predators (consumers of the second order) feed on herbivorous animals, consuming food of a more complex composition, including proteins, fats, amino acids and other substances. In the process of destruction by microorganisms (decomposers) of organic substances of dead plants and animal remains, simple mineral compounds enter the soil and aquatic environment, available for assimilation by plants, and the next round of the biological cycle begins. (Fig. 33).
The emergence and development of the noosphere
Evolution organic world on Earth has gone through several stages. The first is associated with the emergence of the biological cycle of substances in the biosphere. The second was accompanied by the formation of multicellular organisms. These two stages are called biogenesis. The third stage is associated with the emergence of human society, under the influence of which in modern conditions there is an evolution of the biosphere and its transformation into the sphere of the mind-noosphere (from gr.-mind,-ball). The noosphere is a new state of the biosphere, when intelligent human activity becomes the main factor that determines its development. The term "noosphere" was introduced by E. Leroy. VI Vernadsky deepened and developed the doctrine of the noosphere. He wrote: "The noosphere is the new geological phenomenon on our planet. In it, man becomes a major geological force.” V. I. Vernadsky identified the necessary prerequisites for the creation of the noosphere: 1. Humanity has become a single whole. 2. The possibility of instantaneous information exchange. 3. Real equality of people. 4. Growth general level life.5. Use of new types of energy. 6. Exclusion of wars from the life of society. The creation of these prerequisites becomes possible as a result of the explosion of scientific thought in the twentieth century.
Topic - 6. Nature - man: a systematic approach. The purpose of the lecture: To form a holistic view of the system postulates of ecology.
Main questions: 1. The concept of the system and complex biosystems. 2. Features of biological systems. 3. System postulates: the law of universal communication, environmental laws B. Commoner, Law big numbers, Le Chatelier's principle, the law of feedback in nature and the law of the constancy of the amount of living matter.
ecological system- the main object of ecology. Ecology is systemic in nature and in its theoretical form is close to general theory systems. According to the general theory of systems, a system is a real or conceivable set of parts, the integral properties of which are determined by the interaction between the parts (elements) of the system. In real life, a system is defined as a collection of objects brought together by some form of regular interaction or interdependence to perform a given function. In the material there are certain hierarchies - ordered sequences of spatio-temporal subordination and complication of systems. All the varieties of our world can be represented as three sequentially emerged hierarchies. This is the main, natural, physico-chemical-biological (P, X, B) hierarchy and two side ones that arose on its basis, social (S) and technical (T) hierarchies. The existence of the latter in terms of the set of feedbacks in a certain way affects the main hierarchy. Combining systems from different hierarchies leads to "mixed" classes of systems. Thus, the combination of systems from the physico-chemical part of the hierarchy (F, X - "environment") with living systems of the biological part of the hierarchy (B - "biota") leads to a mixed class of systems called ecological. A union of systems from hierarchies C
("man") and T ("technology") leads to a class of economic, or technical and economic, systems. 
Rice. . Hierarchies of material systems:
F, X - physical and chemical, B - biological, C - social, T - technical
It should be clear that the impact of human society on nature, reflected in the diagram, mediated by technology and technologies (technogenesis), refers to the entire hierarchy natural systems: lower branch - to abiotic environment, upper - to the biota of the biosphere. Below we will consider the contingency of the environmental and technical and economic aspects of this interaction.
All systems have some common properties:
1. Each system has a specific structure, determined by the form of space-time connections or interactions between the elements of the system. Structural order alone does not determine the organization of a system. The system can be called organized if its existence is either necessary to maintain some functional (performing certain work) structure, or, on the contrary, depends on the activity of such a structure.
2. According to the principle of necessary diversity the system cannot consist of identical elements devoid of individuality. The lower limit of diversity is at least two elements (proton and electron, protein and nucleic acid, "he" and "she"), the upper limit is infinity. Diversity is the most important information characteristic of the system. It differs from the number of varieties of elements and can be measured. 3. The properties of a system cannot be comprehended only on the basis of the properties of its parts. It is the interaction between the elements that is decisive. It is not possible to judge the operation of the machine from the individual parts of the machine before assembly. Studying separately some forms of fungi and algae, it is impossible to predict the existence of their symbiosis in the form of a lichen. The combined effect of two or more different factors on an organism is almost always different from the sum of their separate effects. The degree of irreducibility of the properties of the system to the sum of the properties of the individual elements of which it consists determines emergence systems.
4. Allocation of the system divides its world into two parts - the system itself and its environment. Depending on the presence (absence) of the exchange of matter, energy and information with the environment, the following are fundamentally possible: isolated systems (no exchange possible); closed systems (impossible exchange of matter); open systems (matter and energy exchange is possible). The exchange of energy determines the exchange of information. In nature, there are only open dynamic systems, between internal elements which and the elements of the environment carry out the transfer of matter, energy and information. Any living system- from the virus to the biosphere - is an open dynamic system.
5. The predominance of internal interactions in the system over external ones and the lability of the system in relation to external forces
actions define it self-preservation ability thanks to the qualities of organization, endurance and stability. An external influence on a system that exceeds the strength and flexibility of its internal interactions leads to irreversible changes.
and death of the system. The stability of a dynamic system is maintained by its continuous external cyclic work. This requires the flow and transformation of energy into this. topic. The probability of achieving the main goal of the system - self-preservation (including through self-reproduction) is defined as its potential efficiency.
6. The action of the system in time is called it behavior. The change in behavior caused by an external factor is denoted as reaction system, and a change in the reaction of the system, associated with a change in structure and aimed at stabilizing behavior, as its fixture, or adaptation. Consolidation of adaptive changes in the structure and connections of the system in time, in which its potential efficiency increases, is considered as development, or evolution, systems. The emergence and existence of all material systems in nature is due to evolution. Dynamic systems evolve in the direction from more probable to less probable organization, i.e. development is underway along the way of complication of the organization and
formation of subsystems in the structure of the system. In nature, all forms of system behavior - from elementary reaction to global evolution - are essentially non-linear. An important feature of evolution complex systems is an
unevenness, lack of monotony. Periods of gradual accumulation of minor changes are sometimes interrupted by sharp qualitative jumps that significantly change the properties of the system. They are usually associated with the so-called bifurcation points- bifurcation, splitting of the former path of evolution. A lot depends on the choice of one or another continuation of the path at the bifurcation point, up to the emergence and prosperity of a new world of particles, substances, organisms, societies, or, conversely, the death of the system. Even for decision systems, the choice result is often unpredictable, and the choice itself at the bifurcation point can be due to a random impulse. Any real system can be represented as some kind of material likeness or iconic image, i.e. respectively analog or sign system model. Modeling is inevitably accompanied by some simplification and formalization of the relationships in the system. This formalization can be
implemented in the form of logical (causal) and/or mathematical (functional) relationships. As the complexity of systems increases, they acquire new emergent qualities. At the same time, the qualities of simpler systems are preserved. Therefore, the overall diversity of the qualities of the system increases as it becomes more complex (Fig. 2.2).
Rice. 2.2. Patterns of changes in the properties of system hierarchies with an increase in their level (according to Fleishman, 1982):
1 - diversity, 2 - stability, 3 - emergence, 4 - complexity, 5 - non-identity, 6 - prevalence
In order of increasing activity in relation to external influences, the qualities of the system can be ordered in the following sequence: 1 - stability, 2 - reliability due to awareness of the environment (noise immunity), 3 - controllability, 4 - self-organization. In this series, each subsequent quality makes sense in the presence of the previous one.
Steam Difficulty system structure is determined by the number P its elements and the number T
connections between them. If in any system the number of private discrete states is investigated, then the complexity of the system FROM is determined by the logarithm of the number of bonds:
C=logm.(2.1)
Systems are conventionally classified by complexity in the following way: 1) systems with up to a thousand states (O <С < 3), относятся к simple; 2) systems with up to a million states (3< С < 6), являют собой complex systems; 3) systems with more than a million states (C > 6) are identified as very complex.
All real natural biosystems are very complex. Even in the structure of a single virus, the number of biologically significant molecular states exceeds the latter value.
The vital activity of an ecosystem and the circulation of substances in it are possible only under the condition of a constant supply of energy. The main source of energy on earth is solar radiation. The energy of the Sun is translated by photosynthetic organisms into the energy of chemical bonds of organic compounds. The transfer of energy through food chains obeys the second law of thermodynamics: the transformation of one type of energy into another comes with the loss of part of the energy. At the same time, its redistribution is subject to a strict pattern: the energy received by the ecosystem and assimilated by producers is dissipated or, together with their biomass, is irreversibly transferred to consumers of the first, second, etc. orders, and then decomposers with a drop in energy flow at each trophic level. As a result, there is no circulation of energy.
Unlike energy, which is used only once in an ecosystem, substances are used repeatedly due to the fact that their consumption and transformation occurs in a circle. This cycle is carried out by living organisms of the ecosystem (producers, consumers, decomposers) and is called the biological cycle of substances.
The biological cycle of substances, or small - the entry of substances from the soil and atmosphere into living organisms with a corresponding change in their chemical form, their return to the soil and atmosphere during the life of organisms and with post-mortem residues and re-entry into living organisms after the processes of destruction and mineralization with the help of microorganisms. Such an understanding of the biological cycle of substances (according to N.P. Remezov, L.E. Rodin and N.I. Bazilevich) corresponds to the biogeocenotic level. It is more accurate to speak about the biological cycle of chemical elements, and not substances, since at different stages of the cycle, substances can be chemically modified. According to V.A. Kovdy (1973), the annual value of the biological cycle of ash elements in the soil-plant system significantly exceeds the value of the annual geochemical runoff of these elements into rivers and seas and is measured by a colossal figure of 109 t/year.
The ecological systems of land and the oceans bind and redistribute solar energy, atmospheric carbon, moisture, oxygen, hydrogen, phosphorus, nitrogen, sulfur, calcium and other elements. The vital activity of plant organisms (producers) and their interactions with animals (consumers), microorganisms (decomposers) and inanimate nature the mechanism of accumulation and redistribution of solar energy coming to the Earth is provided.
The cycle of matter is never completely closed. Part of organic and inorganic substances is taken out of the ecosystem, and at the same time, their reserves can be replenished due to inflow from outside. In some cases, the degree of repeated reproduction of some cycles of the circulation of substances is 90-98%. Incomplete closure of cycles on the scale of geological time leads to the accumulation of elements in various natural spheres of the Earth. Thus, minerals are accumulated - coal, oil, gas, limestone, etc.
2. Fundamental features of modern natural science of the scientific picture of the world
Natural science is the science of the phenomena and laws of nature. Modern natural science includes many natural science branches: physics, chemistry, biology, as well as numerous related branches, such as physical chemistry, biophysics, biochemistry, etc. Natural science raises a wide range of questions about numerous and multilateral manifestations of the properties of nature, which can be considered as a single whole.
Modern diverse technology is the fruit of natural science, which to this day is the main basis for the development of numerous promising areas - from nanoelectronics to the most complex space technology, and this is obvious to many.
Philosophers of all times relied on the latest achievements of science and, above all, natural science. The achievements of the last century in physics, chemistry, biology and other sciences have made it possible to take a fresh look at the philosophical ideas that have developed over the centuries. Many philosophical ideas were born in the depths of natural science, and natural science, in turn, at the beginning of its development was of a natural-philosophical nature. One can say about such a philosophy in the words of the German philosopher Arthur Schopenhauer (1788-1860): “My philosophy did not give me any income at all, but it saved me from very many expenses.”
A person who has at least general and at the same time conceptual knowledge of the natural sciences, i.e. knowledge of nature, will carry out his actions without fail so that the benefits, as a result of his actions, are always combined with a careful attitude to nature and its preservation, not only for the present, but also for future generations.
The knowledge of natural scientific truth makes a person free, free in the broad philosophical sense of the word, free from incompetent decisions and actions, and finally, free in choosing the path of his noble and creative activity.
It makes no sense to list the achievements of natural science, each of us knows the technologies born by him and uses them. Advanced technologies are based mainly on the natural scientific discoveries of the last decades of the 20th century, however, despite tangible achievements, problems arise, mainly caused by the awareness of the threat to the ecological balance of our planet. The most diverse supporters market economy agree that a free market cannot protect African elephants from hunters or Mesopotamian historical monuments from acid rain and tourists. Only governments are capable of enacting laws that encourage the provision of the market with all that man needs without destroying his habitat.
At the same time, governments are unable to pursue such a policy without the help of scientists, and above all scientists who know modern natural science. We need a connection between natural science and governing structures in matters relating to the environment, material support, etc. Without science, it is difficult to keep the planet clean: the level of pollution must be measured, their consequences predicted - only in this way can we learn about the troubles that need to be prevented. Only with the help of the most modern natural sciences and, first of all, physical methods you can monitor the thickness and uniformity of the ozone layer that protects a person from ultraviolet radiation. Only scientific research will help to understand the causes and effects acid rain and smog, affecting the life of every person, to give the knowledge necessary for a man to fly to the moon, to explore the depths of the ocean, to find ways to rid a person of many serious illnesses.
As a result of the analysis of mathematical models popular in the 1970s, scientists came to the conclusion that the further development of the economy would soon become impossible. And although they did not bring new knowledge, they still played an important role. They demonstrated the possible consequences of today's development trends. At one time, such models really convinced millions of people that the protection of nature is necessary, and this is a significant contribution to progress. Despite the differences in recommendations, all models contain one main conclusion: nature cannot be further polluted in the way it is today.
Many problems on Earth can be connected with natural science knowledge. However, these problems are generated by the immaturity of science itself. Let it continue its course - and humanity will overcome today's difficulties - such is the opinion of most scientists. For others, in more for those who only consider themselves to be among the cohort of scientists, science has lost its significance.
Natural science largely reflects the needs of practitioners and, at the same time, is funded depending on the ever-changing sympathies of the state and the public.
Science and technology is not only the main tool that allows people to adapt to constantly changing natural conditions, but also main force directly or indirectly causing such changes.
Along with explicit positive traits inherent in natural science, one should also talk about the shortcomings caused both by the nature of knowledge itself and by misunderstanding on this stage some very important properties of the material world due to the limited knowledge of man. For example, pure mathematicians made a discovery that contradicted the ideas of thinkers of the past: random, chaotic processes can be described by exact mathematical models. Moreover, it turned out that even a simple model equipped with effective feedback is so sensitive to the slightest changes in the initial conditions that its future becomes unpredictable. Is it then worth arguing about whether the Universe is deterministic, if a strictly deterministic model gives results that do not differ from probabilistic ones?
The purpose of natural science is to describe, systematize and explain the totality natural phenomena and processes. The word "explain" in the methodology of science itself requires an explanation. In most cases, it means to understand. What does a person usually mean by saying "I understand"? As a rule, this means: "I know where this came from" and "I know where this will lead." This is how a causal relationship is formed: cause - phenomenon - effect. The expansion of this connection and the formation of a multidimensional structure, covering many phenomena, serves as the basis of a scientific theory, characterized by a clear logical structure and consisting of a set of principles or axioms and theorems with all possible conclusions. Any mathematical discipline is built according to this scheme, for example, Euclidean geometry or set theory, which can serve as typical examples scientific theories. The construction of a theory, of course, involves the creation of a special scientific language, special terminology, a system scientific concepts, which have an unambiguous meaning and are interconnected by strict rules of logic.
After the theory “is verified by experience, the next stage of cognition of reality begins, in which the limits of the truth of our knowledge or the limits of applicability of theories and individual scientific statements are established. This stage is determined by objective and subjective factors. One of the essential objective factors is the dynamism of the world around us. Let us recall the wise words of the ancient Greek philosopher Heraclitus (late 6th - early 5th centuries BC); “Everything flows, everything changes; you cannot step into the same river twice.” Summing up, we will briefly formulate three basic principles scientific knowledge reality.
1. Causality. The first and rather capacious definition of causality is contained in the statement of Democritus: "Not a single thing arises without a cause, but everything arises on some basis and due to necessity."
2. The criterion of truth. Natural scientific truth is verified (proved) only by practice: observations, experiments, experiments, production activities: If scientific theory confirmed by practice, then it is true. Natural-science theories are tested by an experiment connected with observations, measurements and mathematical processing of the results obtained. Emphasizing the importance of measurements, the outstanding scientist D.I. Mendeleev (1834 - 1907) wrote: “Science began when people learned to measure; exact science is unthinkable without measure.
3. Relativity of scientific knowledge. Scientific knowledge (concepts, ideas, concepts, models, theories, conclusions from them, etc.) is always relative and limited.
Common statement: the main objective natural sciences - the establishment of the laws of nature, the discovery of hidden truths - explicitly or implicitly assumes that the truth already exists somewhere and exists in finished form, it only needs to be found, found as a kind of treasure. Great Philosopher In ancient times, Democritus said: "The truth is hidden in the depths (lies at the bottom of the sea)." Another objective factor is related to the imperfection of the experimental technique, which serves as the material basis of any experiment.
Natural science, in one way or another, systematizes our observations of nature. At the same time, one should not consider, for example, the theory of second-order curves as approximate on the grounds that there are no exactly second-order curves in nature. It cannot be said that non-Euclidean geometry refines Euclidean - each takes its place in the system of models, being exact in accordance with internal accuracy criteria, and finds application where necessary. Similarly, it is wrong to claim that the theory of relativity refines classical mechanics - it is different models which, generally speaking, have different areas of application.
Whatever the content of the truth that has occupied the minds of great scientists since ancient times, and no matter how the complex issue of the subject of science in general and natural science in particular, is resolved, one thing is obvious: natural science is an extremely effective, powerful tool, not only allowing to know the world but also of great benefit.
Over time, and especially at the end of the last century, there has been a change in the function of science and, first of all, natural science. If earlier the main function of science was to describe, systematize and explain the objects under study, now science is becoming an integral part of human production activity, as a result of which modern production- be it the production of the most complex space technology, modern super- and personal computers, or high-quality audio and video equipment - it is becoming science-intensive. There is a merging of scientific and production and technical activities, as a result, large scientific and production associations appear - intersectoral scientific and technical complexes "science - technology - production", in which science plays a leading role. It was in such complexes that the first space systems, the first nuclear power plants and many other things that are considered to be the highest achievements of science and technology.
IN Lately specialists in the humanities believe that science is a productive force. This refers primarily to natural science. Although science does not directly produce material products, it is obvious that the production of any product is based on scientific developments. Therefore, when they talk about science as a productive force, they take into account not the final product of one or another production, but that scientific information - a kind of product on the basis of which the production of material values is organized and implemented.
Given such an important indicator as the number scientific information, it is possible to make not only a qualitative, but also a quantitative assessment of the temporal change of this indicator and, thus, determine the pattern of development of science.
Quantitative analysis shows that the rate of development of science, both in general and for such branches of natural science as physics, biology, etc., as well as for mathematics, is characterized by an increase of 5-7% per year over the past 300 years. The analysis took into account specific indicators: the number of scientific articles, researchers, etc. This rate of development of science can be characterized in another way. For every 15 years (half the average age difference between parents and children), the volume of scientific production increases by a factor of e (e = 2.72 - the base of natural logarithms). This statement is the essence of the regularity of the exponential development of science.
The following conclusions follow from this regularity. For every 60 years, scientific output increases by about 50 times. Over the past 30 years, approximately 6.4 times more such products have been created than in the entire history of mankind. In this regard, to the numerous characteristics of the XX century. one can quite justifiably add one more - the "age of science".
It is quite obvious that within the limits of the indicators considered (they, of course, cannot be considered exhaustive for characterizing the complex problem of the development of science), the exponential development of science cannot continue indefinitely, otherwise, in a relatively short period of time, in the near future, the entire population the globe would become scientists. As noted in the previous paragraph, even a large number of scientific publications contain a relatively small amount of truly valuable scientific information. And not every researcher makes a significant contribution to true science. Further development of science will continue in the future, but not due to the extensive growth in the number of researchers and the number of scientific publications produced by them, but due to the involvement of progressive research methods and technologies, as well as improving the quality of scientific work.
Today, more than ever, detailed work is important not only and not so much in criticizing and rethinking the past, but in exploring the paths to the future, searching for new ideas and ideals. In addition to economic issues, this is probably the most significant social order for domestic science and culture. Past ideas exhaust themselves or have exhausted themselves, and if we do not fill the resulting void, then it will be occupied by even older ideas and fundamentalism, already approved by the power and authority of the authorities. This is precisely the challenge to reason today, the departure from which we are witnessing.
3. In all inertial reference systems, the movement occurs according to the same laws - this is the wording ...
a) law gravity; b) Galileo's principles of relativity; c) Newton's laws of classical mechanics
The principle of relativity is a fundamental physical principle, according to which all physical processes in inertial reference frames proceed in the same way, regardless of whether the system is stationary or in a state of uniform and rectilinear motion.
This definition refers to paragraph "b" - Galileo's principles of relativity.
4. Galileo's principles of relativity
Galilean principle of relativity ,
the principle of physical equality of inertial reference systems in classical mechanics, which manifests itself in the fact that the laws of mechanics are the same in all such systems. From this it follows that no mechanical experiments carried out in any inertial system can determine whether the given system is at rest or moves uniformly and rectilinearly. This position was first established by G. Galileo in 1636. Galileo illustrated the similarity of the laws of mechanics for inertial systems using the example of phenomena occurring under the deck of a ship at rest or moving uniformly and rectilinearly (relative to the Earth, which can be considered with a sufficient degree of accuracy an inertial frame of reference): “Now make the ship move at any speed, and then (if only the movement is uniform and without rolling in one direction or the other) in all these phenomena you will not find the slightest change and you will not be able to determine from any of them whether the ship is moving or standing still. motionless ... Throwing some thing to a comrade, you will not have to throw it with more force when he is at the bow, and you are at the stern, than when your mutual position is reversed; drops, as before, will fall into the lower vessel, and not a single one will fall closer to the stern, although while the drop is in the air, the ship will travel many spans.
Motion material point relative: its position, speed, type of trajectory depend on which reference system (reference body) this movement is considered in relation to. At the same time, the laws of classical mechanics ,
i.e., the relations that connect the quantities that describe the motion of material points and the interaction between them are the same in all inertial frames of reference. The relativity of mechanical motion and the similarity (non-relativity) of the laws of mechanics in different inertial frames of reference constitute the content of the Galilean principle of relativity.
Mathematically, the Galilean principle of relativity expresses the invariance (invariance) of the equations of mechanics with respect to the transformations of the coordinates of moving points (and time) during the transition from one inertial frame to another - Galilean transformations.
Let there be two inertial frames of reference, one of which, S, we will agree to consider as resting; the second system, S', moves with respect to S at a constant speed u as shown in the figure. Then the Galilean transformations for the coordinates of a material point in the systems S and S' will have the form:
x' = x - ut, y' = y, z' = z, t' = t (1)
(the dashed values refer to the S’ system, the unprimed values refer to the S system). Thus, time in classical mechanics, as well as the distance between any fixed points, is considered the same in all frames of reference.
From Galileo's transformations, one can obtain the relationship between the velocities of a point and its accelerations in both systems:
v' = v - u, (2)
a' = a.
In classical mechanics, the motion of a material point is determined by Newton's second law:
F = ma, (3)
Where m- point mass, a F- resultant of all forces applied to it. In this case, forces (and masses) are invariants in classical mechanics, i.e., quantities that do not change when moving from one frame of reference to another. Therefore, under Galilean transformations, equation (3) does not change. This is the mathematical expression of the Galilean principle of relativity.
The Galilean principle of relativity is valid only in classical mechanics, in which motions with velocities much less than the speed of light are considered. At speeds close to the speed of light, the motion of bodies obeys the laws of Einstein's relativistic mechanics ,
which are invariant with respect to other coordinate and time transformations - Lorentz transformations
(at low speeds they go over to Galilean transformations).
5. Einstein's special theory of relativity
The special theory of relativity is based on two postulates. First postulate(Einstein's generalized principle of relativity) states: no physical experiments(mechanical, electromagnetic, etc.) produced within a given reference frame, it is impossible to distinguish between the states of rest and uniform rectilinear motion (in other words, the laws of nature are the same in all inertial coordinate systems, i.e. systems moving rectilinearly and uniformly relative to each other). This postulate follows from the results of the famous Michelson-Morley experiment, which measured the speed of light in the direction of the Earth's motion and in the perpendicular direction. The speed of light turned out to be the same in all directions, regardless of the fact of the movement of the source (by the way, these measurements rejected the idea of the existence of a world motionless ether, whose oscillations explained the nature of light).
Second postulate says that the speed of light in vacuum is the same in all inertial coordinate systems. This postulate is understood (including by Einstein himself) in the sense of the constancy of the speed of light. It is generally accepted that this postulate is also a consequence of Michelson's experiment.
The postulates were used by Einstein to analyze the equations of Maxwell's electrodynamics and the following Lorentz transformations, which allow one to express the coordinates and time for a moving system (marked with a dash above) in terms of coordinates and time for a stationary system (these transformations leave Maxwell's equations unchanged):
x' = (x - Vt) / ^ 0.5(m); y' = y(m); z' = z(m); (one)
t' = (t - xV/c^2)/^0.5(sec). (2)
Einstein's velocity addition theorem directly follows from these transformations:
Vc = (V1 + V2)/(1 + V1*V2/c^2)(m/s). (3)
The usual law of addition ( Vc = V1 + V2) only works at low speeds.
Based on the analysis performed, Einstein came to the conclusion that the fact of the system's motion (at the speed V) affects its dimensions, the speed of time and mass in accordance with the expressions:
l = lo/^0.5(m); (4)
delta t = delta to/^0.5(sec); (five)
M = Mo/^0.5(kg). (6)
Zero marks the quantities related to the immobile (resting) system. Formulas (4) - (6) indicate that the length of the moving system is reduced, the passage of time on it (the clock) slows down, and the mass increases. On the basis of formula (5), the idea of the so-called twin effect arose. An astronaut who flew on a ship for a year (according to the ship's clock) at a speed of 0.9998 from, returning to Earth, will meet his twin brother, who has aged 50 years. Relation (6), which characterizes the effect of mass increase, led Einstein to formulate his famous law (6):
E = Mc^2(j).
6. Einstein's general theory of relativity
The general theory of relativity (GR) is a geometric theory of gravity published by Albert Einstein in - years. Within this theory, which is further development special theory of relativity, it is postulated that gravitational effects are not caused by the force interaction of bodies and fieldslocated in space-time, but by the deformation of space-time itself, which is associated, in particular, with the presence of mass-energy. General Relativity (GR) - modern theory gravitation, connecting it with the curvature of the four-dimensional space-time.
Thus, in general relativity, as in other metric theories, gravity is not a force interaction. General relativity differs from other metric theories of gravity by using Einstein's equations to relate the curvature of spacetime to the matter present in space.
General relativity is currently the most successful gravitational theory, well supported by observations. The first success of general relativity was to explain the anomalous precession
perihelion
Mercury. Then, in , Arthur Eddington reported the observation of light deflection near the Sun at the time of a total eclipse, which confirmed the predictions of general relativity. Since then, many other observations and experiments have confirmed a significant number of the theory's predictions, including gravitational time dilation, gravitational redshift, signal delay in a gravitational field, and, so far only indirectly, gravitational radiation. In addition, numerous observations are interpreted as confirmation of one of the most mysterious and exotic predictions of the general theory of relativity - the existence of black holes.
Einstein formulated the principle of equivalence, which states that physical processes in a gravitational field are indistinguishable from similar phenomena with a corresponding accelerated motion. The principle of equivalence became the basis new theory called the general theory of relativity (GR). Einstein saw the possibility of realizing this idea on the way of generalizing the principle of relativity of motion, i.e. extending it not only to the speed, but also to the acceleration of moving systems. If we do not ascribe an absolute character to acceleration, then the distinction of the class of inertial systems will lose its meaning and it is possible to formulate physical laws in such a way that they apply to any coordinate system. This is what general principle relativity.
From the point of view of general relativity, the space of our world does not have a constant zero curvature. Its curvature changes from point to point and is determined by the gravitational field, And time flows differently at different points. The gravitational field is nothing more than a deviation of the properties of the real space from the properties of the ideal (Euclidean) space. The gravitational field at each point is determined by the value of the space curvature at that point. At the same time, the curvature of space-time is determined not only by the total mass of the substance from which the body is composed, but also by all types of energy present in it, including the energy of all physical fields. So, in general relativity the principle of identity of mass and energy of SRT is generalized: Е= mc 2 . Thus, the most important difference between general relativity and other physical theories is that it describes gravitation as the effect of matter on the properties of space-time, these properties of space-time, in turn, affect the movement of bodies, the physical processes in them.
In general relativity, the motion of a material point in a gravitational field is considered as free "inertial" motion, but occurring not in Euclidean, but in space with changing curvature. As a result, the movement of the point is no longer rectilinear and uniform, but occurs along the geodesic line of curved space. It follows that the equation of motion of a material point, as well as a ray of light, must be written in the form of an equation for a geodesic line of curved space. To determine the curvature of space, it is necessary to know the expression for the components of the fundamental tensor (an analogue of the potential in the Newtonian theory of gravitation). The task is to, knowing the distribution of gravitating masses in space, determine the functions of coordinates and time (a component of the fundamental tensor); then it is possible to write down the equation of a geodesic line and solve the problem of the movement of a material point, the problem of the propagation of a light beam, etc.
Einstein found general equation gravitational field (which in the classical approximation turned into Newton's law of gravitation) and thus solved the problem of gravitation in general. The gravitational field equations in general relativity are a system of 10 equations. Unlike Newton's theory of gravitation, where there is one potential of the gravitational field, which depends on a single quantity - the mass density, in Einstein's theory, the gravitational field is described by 10 potentials and can be created not only by the mass density, but also by the mass flux and momentum flux.
Another cardinal difference of general relativity from the physical theories that preceded it is the rejection of a number of old concepts and the formulation of new ones. Thus, general relativity renounces the concepts of “force”, “potential energy”, “inertial system”, “Euclidean character of space-time”, etc.; Non-rigid (deformable) reference bodies are used in general relativity, since there are no solid bodies in gravitational fields and the clock rate depends on the state of these fields. Such a frame of reference (it is called a "reference clam") can move arbitrarily, and its shape can change, the clock used can have an arbitrarily irregular course. General relativity deepens the concept of a field, linking together the concepts of inertia, gravity and space-time metrics, and allows for the possibility of gravitational waves. Gravitational waves are created by a variable gravitational field, uneven movement of masses and propagate in space at the speed of light. Gravitational waves in terrestrial conditions are very weak. There is a possibility of real fixation of gravitational radiation that occurs in grandiose catastrophic processes in the Universe - outbursts of supernovae, collisions of pulsars, etc. But they have not yet been experimentally detected.
Despite the overwhelming success of general relativity, there is discomfort in the scientific community that it cannot be reformulated as the classical limit of quantum theory due to the appearance of irremovable mathematical divergences when considering black holes and space-time singularities in general. A number of alternative theories have been proposed to address this problem. Current experimental evidence indicates that any type of deviation from general relativity should be very small, if it exists at all.
FORMATION OF A MODERN PHYSICAL PICTURE OF THE WORLD PRINCIPLES AND CONCEPTS OF THE EINSTEIN GENERAL RELATIVITY THEORY (GRAVITATION THEORY) Concepts of levels biological structures and organization of living systems
LAWS OF CONSERVATION
Substances come to living organisms from soil, air, water. Water evaporates from the oceans, rises to the layers of the atmosphere, forming rain. Green plants use the water that enters the soil. While maintaining their vital activity, they simultaneously release the oxygen necessary for life. At the same time, without the influence of oxygen, the processes of decomposition and decay of plants could not occur. What is the name of this vicious circle, which provides the possibility of life on Earth, and what are its features?
The main concept of ecology
The biological cycle is the circulation of chemical elements that arose simultaneously with the birth of life on our planet, and which occurs with the participation of living organisms.
The patterns inherent in the circulation of substances solve the main problems of maintaining life on Earth. After all, the reserves of nutrients on the entire surface of the Earth are not unlimited, although they are huge. If these reserves were only consumed by living beings, then at one moment life would have to come to an end. The scientist R. Williams wrote: "The only method that allows a limited amount to have the property of an infinite one is to make it rotate along the trajectory of a closed curved line." Life itself ordered that this method be used on Earth. Organic matter is created by green plants, and non-greens subject it to destruction.
In the biological cycle, each species of living beings has its place. The main paradox of life is that it is maintained through the processes of destruction and constant decay. Complex organic compounds are destroyed sooner or later. This process is accompanied by the release of energy, the loss of information inherent in a living organism. Microorganisms are of great importance in the biological cycle of substances and the development of life - it is with their participation that any form of life is included in the biotic cycle.
Links of the biochain
Microorganisms have two properties that allow them to occupy such an important place in the circle of life. First, they can adapt very quickly to changing environmental conditions. Secondly, they can use a wide variety of substances, as well as carbon, to replenish their energy reserves. None of the higher organisms possesses such properties. They exist only as a superstructure on the fundamental foundation of the kingdom of microorganisms.
Individuals and species of various biological classes are links in the circulation of substances. They also interact with each other through various types connections. The cycle of substances on a planetary scale includes private biological cycles in nature. They are carried out mainly along food chains.
Dangerous inhabitants of house dust
A significant role in the biological cycle is also played by saprophytes - permanent "inhabitants" of house dust. They feed on a variety of substances that are part of house dust. At the same time, saprophytes secrete rather toxic feces that provoke the onset of allergies.
Who are these creatures invisible to the human eye? Saprophytes belong to the arachnid family. They accompany a person throughout life. After all, dust mites feed on house dust, which also includes human skin. Scientists believe that once saprophytes were inhabitants of bird nests, and then "moved" to a human dwelling.
Dust mites, which play an important role in biological circulation, are very small in size - from 0.1 to 0.5 mm. But they are so active that in just 4 months one dust mite can lay about 300 eggs. One gram of house dust can contain several thousand mites. It is impossible to imagine how many dust mites can be in a house, because it is believed that up to 40 kg of dust can accumulate in a human dwelling in one year.
Cycle in the forest
In the forest, the biological cycle is most powerful due to the penetration of tree roots into the depths of the soil. The first link in this turnover is usually considered the so-called rhizosphere link. A rhizosphere is a thin (3 to 5 mm) layer of soil around a tree. The soil around the roots of a tree (or "rhizosphere soil") tends to be very rich in root exudates and various microorganisms. The rhizosphere link is a kind of gate between wildlife and non-living.
The consumption link is in the roots, which absorb minerals from the soil. Some of the substances are washed away by rainfall back into the soil, however for the most part the return of nutrients is carried out during two processes - litter and waste.
The role of fall and fall
Waste and waste have different meanings in the biological cycle of substances. The litter includes tree cones, branches, leaves, grass residues. Researchers do not include trees in the litter - they are classified as litter. Waste decomposition can take decades. Sometimes the waste can serve as material for feeding other tree species - but only after reaching a certain stage of decomposition. Waste contains many substances belonging to the class of ash. They slowly enter the soil and are used by plants for further life.
What does fall depend on?
The litter has a slightly different meaning in the biological cycle. During the year, its entire volume passes into the litter layer and undergoes complete decomposition. Ash elements enter the biotic circulation much faster. However, in fact, the litter is part of the biological cycle already when the leaves are on the tree. The litter rate depends on many factors: climate, weather in the current and previous years, and the number of insects. In the forest-tundra it reaches several centners, in the forests it is measured in tons. The largest amount of litter in the forests occurs in spring and autumn. This indicator also differs depending on the year.
As for the organic composition of needles and leaves, they undergo the same changes during the cycle. Unlike litter, green leaves are usually rich in phosphorus, potassium, and nitrogen. The litter is usually rich in calcium. to the biological cycle big influence provided by insects and animals. For example, leaf-eating insects can significantly accelerate it. However, the greatest influence on the cycle rate is exerted by animals in the process of litter decomposition. Larvae and worms eat and grind the litter, mix with the upper layers of the soil.
Photosynthesis in nature
Plants can use sunlight to replenish their energy reserves. They do it in two steps. At the first stage, light is captured by the leaves; in the second, energy is used for the process of carbon sequestration and the formation of organic substances. Biologists call green plants autotrophs. They are the basis for life on the entire planet. Autotrophs have great value in photosynthesis and biological cycle. The energy of sunlight is converted by them into stored energy through the formation of carbohydrates. The most important of these is the sugar glucose. This process is called photosynthesis. Living organisms of other classes can access solar energy by eating plants. Thus, a food chain appears, providing the cycle of substances.
Patterns of photosynthesis
Despite the importance of photosynthesis, long time he remained unexplored. Only at the beginning of the 20th century, the English scientist Frederick Blackman set up several experiments with the help of which it was possible to establish this process. The scientist also revealed some patterns of photosynthesis: it turned out that it starts in low light, gradually increasing with light streams. However, this only happens up to a certain level, after which light amplification no longer speeds up photosynthesis. Blackman also found that a gradual increase in temperature with increased light promotes photosynthesis. Increasing the temperature in low light does not speed up this process, nor does increasing light in low temperature.
The process of converting light into carbohydrates
Photosynthesis begins with the process of getting photons of sunlight into the chlorophyll molecules located in the leaves of plants. Chlorophyll is what gives plants green color. The capture of energy occurs in two stages, which biologists call Photosystem I and Photosystem II. Interestingly, the numbers of these photosystems reflect the order in which scientists discovered them. This is one of the oddities in science, since the reactions first occur in the second photosystem, and only then in the first.
A photon of sunlight collides with 200-400 chlorophyll molecules in a leaf. In this case, the energy increases sharply and is transferred to the chlorophyll molecule. This process is accompanied chemical reaction: the chlorophyll molecule loses two electrons (they, in turn, are accepted by the so-called "electron acceptor", another molecule). And also when a photon collides with chlorophyll, water is formed. The cycle in which sunlight is converted into carbohydrates is called the Calvin cycle. The importance of photosynthesis and the biological cycle of substances cannot be underestimated - it is thanks to these processes that oxygen is available on earth. Minerals obtained by man - peat, oil - are also carriers of energy stored in the process of photosynthesis.