Distinctive properties of biological systems: the all-around comparison with other natural systems.
Several tens of distinctive features of biological systems were distinguished by various researchers. But strict differences between animate and inanimate systems can be defined only through a systematic comparison of all of them. Based on the all-round comparison, four unique properties of living systems are distinguished in this paper. They are integrated and contain particular biological properties. These properties help to formulate the integrated definition of life. Finally, some consequences from the elaborated conception are given.
The difference between animate and inanimate nature was considered by many scientists and philosophers. A scientific approach to a response on this question implies a formulation of unique properties of biological systems, which are not peculiar to any other natural system. Many various properties (features) were distinguished as distinctive for living systems. The latest summarizing in this area is the book "Fundamentals of Life," (6) which contains around 80 short definitions of life and 25 papers, written by very competent scientists. They distinguished 47 distinctive properties of living beings, among them self-reproduction (27 mentions by different authors), capability of (negentropy) evolution (26), ability to extract free energy and matter from the environment (16), ability to perform and control metabolism (15), ability to store and replicate genetic information (12), ability to grow (10), capable of thermodynamic and chemical disequilibrium (9), ability to have autocatalysis (9), existence of genome and genetic code (7), availability of membranes as geochemical barriers (7), at the highest level of complexity (7), foresight and ability to modify own behavior (7), composed of carbon-based polymers (6), etc. Distinguishing these properties of biological systems, however, was being conducted without any comparison with non-biological natural systems. So, we cannot recognize which of the properties are actually peculiar to only living systems and which might display in inanimate systems. To clear up this question, we must carry out an all-round comparison of biological systems with the rest of natural systems. This work is an attempt to make a step in this direction.
The clearly formulated unique features of living systems might be a guideline in our efforts to understand the origin of life. We have no chance to solve the origin of life problem until we comprehend better what life is. The essence of life is characterized by unique, or key, properties of living systems. In fact, just these properties fill the gap between animate and inanimate nature, and show what new appeared during the origin of life process. This knowledge would permit us to restrict the admissible corridor of conditions leading to the appearance of living beings.
This paper consists of three parts. In the first, the initial separating line between the biological and some other types of natural systems is drawn. It is based on the original classification of natural systems. The second part is devoted to consideration of the universal spontaneous and non-spontaneous processes occurring in various types of natural systems. In the third part, the unique properties of living systems are summarized, and some consequences from the elaborated conception are outlined.
I. Types of Natural Systems
1) Original Classification of Natural Systems
The original classification of natural systems is used for the comparison of biological and non-biological systems. The initial version of the classification was suggested some years ago. (8) All main types of natural systems existing in the universe are taken into consideration in this classification. A principal criterion of the classification is availability of surplus or deficit of free energy in a system in respect to its surroundings, i.e., gradient of free energy between them. As known, free energy provides the ability of a system to carry out work. This universal criterion allows a comparison of different types of natural systems. The notion of "work" is most generally equivalent of transformations, occurring in an environment with radiation of a star, eruption of a volcano, existence of biological organisms, activity of human society. On the other hand, this criterion clearly distinguishes biosystems from many types of natural systems which cannot execute work by their own activity (like a stone or hardened flow of lava). So, the chosen fundamental criterion seems very appropriate for all-round comparison of natural systems.
Free energy of simple physical and chemical systems can be estimated from the following equation:
A = U - TS, (1)
with A--free energy, U--inner energy, T--absolute temperature, S--entropy.
This equation established the dependence between inner and free energy of a system. The whole inner energy of a system can be subdivided into two parts: the first one is bound energy, which cannot be converted into work, and the second one is free energy, which can be converted into work. Macroscopic work under isothermic conditions is defined by the difference of free energy (initial and final states of a system), but not by the difference of inner energy. This is a physical sense of the notion "free energy." During isothermic transition of a system from the state with value of free energy [F.sub.1] into the state with value [F.sub.2], the system carries out work A = [F.sub.1] - [F.sub.2] (in this case a reversible process). There exists free energy of Helmholtz, which proceeds under a constant temperature and volume, and free energy of Gibbs, which takes place under constant pressure. The value of free energy of a simple physical or chemical system can be precisely estimated by means of definite equations. Thus, we can precisely estimate a change of free energy during a chemical reaction. Free energy of biological systems cannot be exactly estimated due to their high complexity, however, this notion makes general sense. This quality of the notion "free energy" is very important, because it allows comparison of simple and complex systems. The quality is one more worth of the chosen criterion, as various natural systems are at quite different levels of organization in the developing universe.
Using the chosen criterion, natural systems existing in the universe can be united into the following two vast groups (Table 1):
1. Active, or self-complicating systems, with an excess of free energy with respect to the environment; in fact, these are the systems that by their inner nature can concentrate free energy. This is responsible for their ability to execute work in the environment. They are: stars and their associations, active planets and satellites (possessing volcanic activity), magmatic systems (vertical columns of magmatic chambers or separate chambers), hydrothermal systems (rising flows of hot water solutions), all biological systems (from a cell to biosphere), and all social systems of different ranks whose activity in the environment is maintained by free energy generating in people.
2. Passive, or non-self-complicating systems, that do not possess an excess of free energy with respect to the environment; in consequence, these systems are unable to execute work in the environment independently, without application of external forces. They are: black holes, cosmic gas/dust clouds, massifs of igneous rocks, stones and crystals, organic remains of soils, archaeological monuments of past civilizations, etc. The atmosphere and the hydrosphere take special place among non-self-complicating systems. Generally, they do not possess a surplus of free energy in respect to the surroundings (the lower border--the lithosphere--is warmer, while the upper one--outer space--is colder), but nevertheless they are able to carry out work at the expense of inner fluctuations (surf, hurricane).
The ability of active systems to carry out work in the surroundings is the first distinctive feature differing them from passive systems. It is not sufficient to clearly differentiate these groups of systems, due to the capacity of the Earth's atmosphere and hydrosphere to execute work. The ability of active systems to inner structural complication represents the second feature. All active systems go through the point of origination, development with its peak, aging, and dying. The cycle of their existence implies a rise of the level of complexity (organization) on the ascending branch of development and its slower decline on the descending branch. The complexity increases through synthesis and cooperation (Table 2). Four universal stages in the cycle of existence of active systems have been distinguished before: 1) growth, increase in size; 2) internal development to maturity; 3) maturity, stationary state; 4) aging. (8)
Ability of active systems for self-development with structural complication makes it possible to use one more term for their designation--"a natural self-complicating system." A self-complicating system can be defined as an open natural system, possessing a surplus of free energy and active exchange of energy and matter with the environment, and going through the point of origination, the process of development with its peak, aging and dying. There exist self-complicating systems of different ranks. For instance, an active planet or the biosphere is macrosystems, while a cell or a cybotactic grouping in magma represent self-complicating microsystems.
Particularly, the term "a self-complicating system" is correlated with the term "a natural self-organizing system." The notion of a self-organizing system was suggested by W.R. Ashby in 1947 and elaborated more definitely later. (1) He considered a self-organizing system as a self-adapting system whose adaptation to changing conditions or optimization of the control processes is realized by means of changes in the control structure. In fact, the term "natural self-organizing system" can be applied only to the biological and social systems with their developed control structures. As for stars and active geological systems, a question about the availability of control structures in them and their ability for self-adaptation is very disputable.
To summarize, active systems possess three principal features that distinguish them from the passive systems:
1. A surplus of free energy providing their ability to carry out work in the surroundings.
2. Self-complication of internal structure at the ascending branch of their existence.
3. Active exchange of energy and matter (as well as information in complex systems) with the environment.
2. Initial Separating Line Between Animate and Inanimate Natural Systems
As a result of consideration of the original classification of natural systems, the question concerning a criterion for finding a difference between animate and inanimate nature has been converted into another plane. In fact, this question subdivides into the following two questions: the difference between biological systems and passive natural systems and the difference between the biological and all other active systems. Passive and non-biological active systems represent the whole inanimate nature.
All biological systems are active. So, the given definition of an active system and the listed three characteristic features can serve as the first separating line between animate and inanimate nature, just between the biological and passive systems (Fig. 1). This line clearly separates these groups of natural systems, however, some cases demand special discussion. Some scientists doubt that there exists a strict boundary between a cell and some kinds of passive microsystems. Thus, sometimes prebiotic organic microsystems, such as RNA-World macromolecules or proteinoide microspheres, are considered to be very close to the living systems. (5,15) Actually, the ability of carboneum atoms to form steady chains and cycles with each other, as well as with hydrogen, nitrogen, and oxygen, causes a great number of organic compounds. Possessing the highest level of chemical complexity, macromolecules of RNA-World and polyamino acids complete the chemical evolution of matter (Table 4). However, prebiotic microsystems do not possess the common features of self-complicating systems listed above: excess of free energy (providing the ability to carry out work) and active exchange of energy/matter with the environment. Life is not simply a continuation of the chemical evolution of matter, as we can see in Table 3. Another kind of passive microsystem that is compared sometimes with a functioning cell is a growing crystal. Definition of an active system also makes it possible to clearly see a difference between them. A growing crystal increases in size, but does not complicate a structure of the crystal lattice. The Earth's atmosphere and hydrosphere, being kinds of passive macrosystems, possess ability to carry out work. But they do not complicate their own inner structures in time. During their evolution, only increases in size of the oceans and a change of the atmosphere's composition, initiated by living beings, took place. At the same time, the biotic component of the biosphere is continuously complicating.
[FIGURE 1 OMITTED]
So, the suggested classification is a good basis to draw the first separating line between animate and inanimate nature, distinguishing biological and passive systems. But another approach should be used in order to draw one more separating line inside the group of active systems, just between biological and non-biological ones (Fig. 1). At first sight, a star or magmatic system is so unlike a biological system that we can find a lot of distinctions. It's true, but a profound sight to the deepest regularities of their functioning opens many common features that show unity of nature. Three principal common features have been formulated above; some others were considered earlier. (10) Like a living being, a magmatic system maintains homeostasis. This process is connected with continuous redistribution of matter and energy by means of their flows ("geological metabolism"). A magmatic system assimilates a huge volume of different host rocks during its own growth. Nevertheless, exploration of massifs of magmatic rocks shows amazing constancy of their composition in vast areas. According to the ionic-cybotactic theory, magma consists of microscopic "cybotactic groupings" of two types--long-range (including oxides Fe, Mg, Ca, etc.) and short-range ([Si.sub.x][O.sub.y]). (4) These groupings continuously appear, grow, and destroy in magma, like living organisms in the biosphere.
Active natural systems are characterized by continuous internal and external dynamic processes. Considering their peculiarities in various systems, we get a chance to find clear distinctions between them and to draw the second separating line. Basic distinctions can be found only through analysis of fundamental or universal processes occurring in the universe. There are some pairs of universal processes: "reversible--irreversible", "pressing--expansion," etc. The most appropriate for our purpose are opposite "spontaneous--non-spontaneous" universal processes. A change of balance between them defines change of free energy and entropy in a system. So, this new approach develops further the initial consideration of natural systems, based on the gradient of free energy as a principal criterion.
II. Universal Spontaneous and Non-Spontaneous Processes in Natural Systems
1. General Characteristics of the Processes
The processes, changing the level of organization of a system and its energetic gradients, are united into two universal types--spontaneous, or basic, and non-spontaneous, or coupled. The first type leads to transition of a system to its most probable state, and the second to its least probable state. Spontaneous processes proceed always and elsewhere in the universe (that's why they are designated as basic). Non-spontaneous processes can occur only in the presence of spontaneous ones (that's why they are coupled). Spontaneous processes proceed by themselves, while non-spontaneous processes demand an expenditure of energy. For instance, the heat transfer from a warm body to a cold one is a basic process. On the contrary, the heat transfer from cold to warm body is a coupled process. Commonly, spontaneous processes decrease initial energetic gradient, while non-spontaneous processes increase it. Opposite directions of the gradient changing is the best criterion to differ these types of the processes.
A gradient is a vector showing direction of the strongest change of any value from one point of space to another. The stronger the change the bigger the gradient. There are various types of gradients: concentration, temperature, pressure, electric field, gravity, etc. Any gradient, giving an impulse to any process, is an energetic gradient. For instance, an electric field gradient is energetic. Discharging of an electric battery due to a basic process decreases the gradient, while charging of a battery through a coupled process increases it. Diffusion is a spontaneous process and active transport in a living organism is a non-spontaneous one. The first one decreases concentration gradients in any system, while active transport increases it by means of the mass transfer against the gradients. The universal processes under consideration change free energy and entropy in a system. The notion "free energy" correlates with the constructive notions such as "order," "organization," "information," while entropy correlates with destructive ones--"chaos," "disorganization," "misinformation." In common cases, basic (spontaneous) processes lead to an increase of entropy and chaos in a system, and the coupled (non-spontaneous) processes lead to increase of free energy, information, and the level of organization. Distinctions between spontaneous and non-spontaneous processes are summed up in Table 3. Of course, these distinctions display clearly only in simple systems. In complex systems, where plenty of processes exert influences upon each other, the distinctions display themselves only as tendencies.
Summing up, we come to the conclusion that basic and coupled processes can be "indicators" of increment or reduction of the level of organization (order) of natural systems. Development or degradation of a natural system depends on the balance of these processes at a definite moment. So, the total balance "summary energetic effect of non-spontaneous processes (E+) to summary energetic effect of spontaneous processes (E-)" can be considered as a principal characteristic of a natural system. Positive balance (E+ > E-) means that free energy increases in a system at the expense of a decrease in entropy (or free energy increases faster than entropy increases), and vice versa.
2. Spontaneous and Non-spontaneous Processes in Passive and Active Natural Systems
Only basic processes, resulting in destructive events, take place in many kinds of passive systems. Massifs of igneous rocks, formed mountains, stones or crystals, or hardened flows of lava are gradually destroyed. The same happened with the planets and satellites that lost geological (volcanic) activity (the Moon is one example). Archaeological monuments of past civilizations are gradually ruined, too. The coupled processes occur in some kinds of passive systems, like the atmosphere and the ocean. Thus, from time to time a gradient of pressure increases in a local part of the atmosphere (the result of a coupled process). Then a wind or hurricane--a basic process--takes place and decreases the gradient. These events are the usual fluctuations in systems possessing an agile medium. On the whole, passive systems are characterized by negative energetic balance between the two opposite universal processes. (E+ < E-). This peculiarity corresponds to disability of passive systems for self-complication and self-organization.
Macro- and micro-fluctuations of different ranks regularly appear in various parts of active non-biological systems. Any fluctuation is initiated by an increase of an energetic gradient; then a development of spontaneous processes decreases the gradient. For instance, pressure and temperature rising in a magma chamber lead to an increase of the energetic gradient between the chamber and surroundings. During the following volcanic eruption, the energetic gradient decreases. Fluctuations in plasma of stars are initiated by a change of the inner energetic gradients, too. During the formation of hydrothermal mineral (ore) deposits, a basic process of diffusion disseminates chemical elements, while a coupled process concentrates some of them. (7) These opposite processes always proceed simultaneously.
Thus, both types of universal processes take place in active non-biological systems. These systems use available surplus of free energy for their own development, including the growth of internal gradients and complication of the inner structure. A growth of gradients is achieved by means of a coupled process, proceeding simultaneously with a basic one. These systems are able to increase a surplus of free energy at the ascending branch of the cycle of existence. So, active non-biological systems can possess the positive energetic balance (E= > E-) at the ascending branch, as a rule.
Numerous biophysical, biochemical, and nervous-mental processes proceed in biological systems. Some processes lead to the increase of entropy and destruction of a biosystem; they belong to the spontaneous type. Other processes lead to the increase of free energy and self-renovation (or self-organization) of a biosystem; they belong to the non-spontaneous type. Let's consider some concrete examples of these processes. Permanently appearing damages in DNA chains are a kind of destructive (spontaneous) process. Restoration of the DNA chains, carried out by means of the reparation ferments belongs to self-renovating (non-spontaneous) processes. (3) The synthesis of proteins with a broken primary structure is a basic process, while their taking out from the organism by means of the immune system represents a coupled process. P.C. Bragg (2) figuratively describes two opposite flows of thoughts that are streaming in our brain, in our psyche. The first flow of positive thoughts brings people to success, health, and happiness (renovating, or coupled process). The second flow of negative thoughts brings people to illness, premature old age, misfortunes, and failures (destructive, or basic process).
The total energetic balance between coupled (self-renovating) and basic (destructive) processes defines the tendency of the evolution of a biosystem. The positive balance (E+ > E-) provides the tendency to sustainable development of a biosystem that makes it viable. The negative balance (E+ < E-) leads to degradation and the following extinction due to the natural selection. With the last resort of equal balance (E+ = E-), the system can exist in the stable environment for a long time, but it isn't able to achieve self-perfection. For an analogy, prevalence of the national income over national expenses is the total positive balance; it leads to the sustainable development of the country, and vice versa.
III. Unique Properties of Biological Systems and its General Way of Organization
Summarizing the data from the previous parts, four actually unique properties biosystems can be distinguished from the several tens properties, which were substantiated by various scientists. They have been considered in this part. Each of these four properties was based as a feature of biosystems earlier by different authors. The new point given below is, firstly, their combination, and secondly, clearly distinguishing them from the rest biological properties through systematic analysis of natural systems. These four properties have made it possible to draw the second separating line between animate and inanimate nature, differing biological and non-biological active systems (Fig. 1).
1. Comparison of Active Systems and Four Unique Biotic Properties
As it was noted, all active systems can increase their surplus of free energy in respect to the surroundings. But directions for getting free energy are different for biological and non-biological active systems. Accumulation of free energy in a star occurs due to successive starts of new and more energy-productive thermonuclear reactions at the earliest stage of evolution. Volcanic processes on active planets support by means of energy saved in the melted core and producing in a radio-active decay process. Magmatic and hydrothermal systems get energy through heat flows rising from the bowels of a planet. So, all non-biological active systems either use their own potential energetic reserves, or get an inflow of energy from the surroundings. In both cases they do NOT actively extract free energy from the environment. The vector of energy exchange (through light, heat, and work) directed from these systems enrich surroundings with energy (Fig. 2). On the contrary, biosystems accumulate free energy only at the expense of active extraction from the environment, in the process of energy, substance, and information exchange. Their vector of free energy exchange is directed inside. Living beings actively extract free energy from the environment and simultaneously transform it (Fig. 2). This maintains their positive energetic balance. So, we can define the first unique property of a biosystem as its ability for active extraction of free energy from the environment. Some fundamental works were devoted to the basis of this property. One of the most important of them was written by E. Shroedinger. (14) What is the cause of this clear distinction? To understand it, let's consider peculiarities of interactions between active systems and their surroundings.
[FIGURE 2 OMITTED]
According to the Le Chatelier principle, any influence on a system, executed by means of a change of the external conditions, initiates a counteraction of the system. Initiated counteraction weakens the effect of the external influence. The ratio "Energetic effect of external influence / Energetic effect of the counteraction" is a very appropriate notion for further comparison of biological and non-biological systems.
Passive systems always exert the weakened counteraction to an external influence, i.e., this ratio is positive. A billiard ball, impacted by another one, exerts counteraction to the influence at the expense of inertia and friction. Energy of an action of this kind is always higher than energy of counteraction. An external influence to an active non-biological system is a cause of a self-regulation process appearing in it. Self-regulation is also a kind of weakened counteraction to external influence. For example, a drastic fall of temperature in host rocks initiates rapid cooling of the adjoining zone of a magmatic chamber. The magmatic chamber responds to the influence by means of an increase in this local zone concentration of easily melted silica components and fluids. An abundance of these components decreases the temperature of magma crystallization in the rapidly cooling zone, and the process of magma crystallization stops. Such self-regulation maintains the integrity of magmatic systems. However, continuous cooling exhausts in the long run energetic reserves of magmatic chamber, and it transforms into a massif of igneous rocks. So, self-regulation itself cannot turn a process of energy exchange into a transition of heat from cool body (host rocks) to hot body (magmatic chamber), i.e., against the energetic gradient. That's why self-regulation is the way of passive counteraction, or weakened reaction to external influence. Correspondingly, the ratio "Energy of external action/Energy of counteraction" is also positive. The non-biological active systems do not possess any internal mechanism that might strengthen the counteraction.
Unlike the considered types of natural systems, biosystems are able to have an active counteraction, or to have the intensified reaction to an external action. Thus, a tree can compensate for a lost branch by means of several new branches. An ant is able to carry a load that is much heavier than its own weight. A muscle may develop an extraordinary powerful effort. On the whole, the ratio "Energy of external action/Energy of counteraction" can be a negative (that usually characterizes viable forms of life) or positive (degrading forms of life). A living being aspires to compensate spent energy in plenty. For instance, a muscle compensates the spent energy in plenty some time after work is over. There is a general principle for a living organism: working structures develop, non-working ones atrophy. So, the second unique property of biosystems is their ability for the intensified counteraction to an external action (influence). At the expense of what living organism is it able to execute an intensified reaction? Let's consider in general this mechanism.
Spontaneous processes proceed inevitably and continuously in both closed and open systems. Non-spontaneous processes possess impulsive character and can occur only in open systems, through the expenditure of energy and efforts. An increase of entropy or free energy in an open system depends on the total balance of basic and coupled processes. Open systems get various external influences and exert back influences on the environment. This influence exchange maintains the open status of the system. If there is no exchange of influences, it leads to transformation of an open system into a closed one, increase of entropy in it, and the following simplification of the structure. So, the influence exchange is a necessary factor for supporting coupled processes in a system.
The ability for an intensified responding reaction of a living organism is provided by a supply of free energy, on the one hand, and coordination of all its structures and functions for selection of the most adequate response, on the other hand. So, the intensified reaction of a biotic system to an external influence clubs together with the most profitable (i.e., expedient) way of counteraction, directing into the environment, and its high motive power. Just this combination of the factors permits the responding reaction to prevail over the initial external action, and to turn free energy flow from the environment into a biotic system. Expenditure of energy that makes the intensified counteraction possible restores with an energetic profit in some time. The positive free energy gradient of a biotic system in respect to the environment maintains its ability for an intensified reaction. So, high energy of a responding reaction is an insufficient condition for sustainable development of a living being. A biotic system must possess one more necessary property--the ability to coordinate its own behavior in order to achieve most favorable conditions of existence, i.e., optimal conditions inside abiogenous and biogenous limiting factors (optimal range of temperature, abundance of food, etc.). The most exact term for designation of this feature is "expediency." So, the third unique property of a biosystem is its expedient behavior, or more strictly expedient character of its interaction with the environment. Expedient behavior is based on the information accumulated inside biosystems. Realizing an expedient behavior, unicellular organisms acquired ability for taxis. In general case, plants aspire to grow closer to intensive sunlight. An animal moves seeking food.
Simultaneously with the intensified (active) responding reaction, a biosystem possesses the weakened (passive) reaction. The intensified reaction is a unique property of biosystems, while the weakened one is peculiar to all active systems (as biological as non-biological). As it was considered, the weakened responding reaction displays through self-regulation. For instance, a damaged tree can restore its functions by means of direct healing of broken branches (passive counteraction) and by means of the appearance of new branches (active counteraction). Reaction of a human when it is cold can consist of putting on gloves (active counteraction) and transference of heat energy of the organism into cooling hands (passive counteraction).
Let's conclude. All actions of a biological system in the environment are in the long run various kinds of passive and active responding reactions to external influences, i.e., they are initiated by them. Free energy that an organism extracts from the environment is in fact the difference between the energy of external actions and the energy of the intensified-expedient counteraction. The absence of external influences means the absence of intensified back reactions. Therefore, extraction of free energy in this case also equals nought. On the other side, too strong external actions exceed the ability of an organism for adaptation and repress its activity. These notions correspond with the theory of stress by H. Selye. Optimal stress is necessary for life. An absence of stress as well distress leads to death. (13)
Self-renovation processes prevail over destruction in any viable living system. This is the inevitable result of the positive energetic balance that is peculiar to systems of the kind. So, the regular self-renovation can be considered as the fourth unique property of a biosystem. The self-renovation proceeds on different levels: intra-cellular (restoration of nucleotide chains, renovation of proteins), intra-organismic (self-replication of DNA, self-renovation of cells), intra-specific (self-reproduction of organisms), and intra-biospheric (self-renovation of species). To summarize, various kinds of self-renovation in biosystems are provided at the expense of energy of the universal coupled processes (more exactly, at the expense of the difference between opposite coupled and basic processes).
2. Integration of the Unique Characteristics and the Original Definition of Life
Let's enumerate the distinguished four unique properties of living systems:
1. Ability for active extraction of free energy from the environment.
2. Ability for the intensified counteraction to an external influence.
3. Expedient behavior, or (stricter) character of interaction with the environment.
4. Regular self-renovation.
These characteristics are most integrated and can be considered as key for biological systems. The most typical features of biosystems, which were mentioned by other authors and listed in the introduction, either take part in these integrated properties, or follow then as consequences, or are non-unique ones in the strict sense and peculiar also to non-biological systems. Thus, the first property implies thermodynamic and chemical disequilibrium of a biosystem, presence of membranes as geochemical barriers (maintaining disequilibrium), accumulation of information (that correlates with free energy), and formation of specific genetic structures. Accumulation of free energy and information in the long run inevitably leads to negentropy evolution and a connected increase of complexity. Self-replication of genes and self-reproduction of organisms/species are kinds of a general self-renovating process that proceeds on different levels--intraorganismic, intra-specific, and intrabiospheric. Foresight and the ability to modify their own behavior are kinds of expediency. The second unique property is most latent in comparison to others but maybe even more substantial, because it shows the way of free energy accumulation. The ability of an intensified responding reaction is connected with irritability that is considered very seldom as an important distinctive biological feature. The rest of the typical features of biosystems, listed in the introduction, are not strictly peculiar to only animate nature. The ability to grow possesses, for instance, a magmatic system. Many kinds of prebiotic microsystems or organic particles in an ocean, being non-living matter, are composed of carbon-based polymers. Continuous exchange of matter and energy takes place in biological (metabolism) as in non-biological active systems. Of course, metabolism in a biotic system proceeds on a qualitatively higher level, including such specific processes like cyclic chemical processes, autocatalysis, and feedback loops.
The essence of any phenomenon is usually expressed through a definition. Some various definitions of life can be offered based on the distinguished four unique properties of biosystems. The author's version is: "Life is a highly organized structure able to exert intensified and expedient counteraction to spontaneous destructive processes and developing through regular self-renovation." This is a corrected version of the definition suggested earlier. (11) The forms of life, which cease to satisfy the given definition, lose viability and are eliminated in the long run with natural selection.
Less fundamental features of biosystems follow this definition. Thus, the membranous principle of a living being's constitution appeared as a result of growth and differentiation of energetic gradients. Irritability is an initial reaction to an external influence that forestalls further intensified response. Ability of living systems for accumulation of free energy serves the general latent cause of negentropy biological evolution. This latent cause defines also the process of biological information accumulation and gene emergence, because free energy and information are correlated notions.
Considering life phenomenon in the global process of self-organization of the universe, we can come to the following conclusions: Life displays through existence of biological systems that take up the definite position in the growth of complexity in the universe--between geochemical and social active systems (Table 4). Previous development of astrophysical and geochemical active systems created the necessary level of order in the universe making the origin of life possible. A leap in the growth of complexity is the first feature designating the transition from geochemical to the biological level. Biological systems appeared as a superstructure over the lower organized systems and resulted in creation of an extra-complex natural supersystem. Before biological systems appear on a planet, active and passive geological systems represent the inseparable whole, i.e., a medium in the physical (chemical, geological), or cosmological sense. Active non-biological systems discharge energy, passive systems accept it. Living organisms possess absolutely new quality--the ability for active extraction of free energy. As soon as primary cells have been originated they start to extract free energy from the medium and transform it into the environment (i.e., part of physical/geological medium transformed by life). In this sense, the biological systems are separated from the physical medium. So, since this great event the absolutely new stage of planetary development began on Earth, as well as on other inhabited planets and circumstellar habitable zones (which still should be discovered and explored). Figuratively speaking, active non-biological systems are able to develop only with "direct favorable wind (influences)," i.e., with permanent inflow of heat energy, like a boat with a fixed sail in the ocean. Their movement directed by a "wind." Living systems are able to use a "wind" of any direction (as favorable and unfavorable influences), like a brigantine changing sails and choosing its own way in the open sea.
3. Some Consequences From the Elaborated Conception
Consequence for the origin of life. The ability of living beings for an intensified responding reaction, being one of the unique biological properties, postulates the following fact: life is able to develop only under various external influences. The absence of regular external actions, i.e., fluctuations in the environment, gives a living organism no chance to display its own intensified counteraction. This thesis is relevant to the medium of the origin of life. Initial life forms must regularly get strong influences from the outside world to create the mechanism of strengthening of the counteractions. So, significant fluctuations in a medium are one more strict condition for the origin of life, in addition to three well known ones (liquid water, organic matter, and source of energy). Considering two alternative liquid media for the origin of life--an ocean and a hydrothermal system, we can come to the conclusion that only the second one fits this requirement. An ocean is a near-equilibrium medium, while fluctuations in hydrothermal systems are maintained permanently. Fluctuations in hydrothermal systems are initiated due to contradictory interaction between descending lithostatic pressure of host rocks and ascending hydrodynamic pressure of rising hot solutions. (12)
Consequences for the theory of biological evolution. The suggested conception postulates that biotic systems (i.e., proper living beings) are active constituents in respect to the environment. Their activity is provided by the positive free energy gradient. The modern synthetic theory of biological evolution is based on four main factors: mutation process; population waves; isolation; and natural selection. In fact, these factors are external in respect to living beings. Their transforming influence directs to living beings from outside. However, it follows from the elaborated conception that living systems accumulate free energy by their own inner nature. This process must inevitably lead to a generation of life motive power inside organisms. As a result of the combination of motive power and expediency, the tendency to self-transformation of living systems from inside should also be displayed. Taking this reason into account, the fifth factor of biological evolution can be formulated. This is internal latent striving of living systems for self-reformation, i.e., to renew their own structure and shape in accordance to conditions in the environment. So, in general, case biological evolution can be considered as a two-sides process. The appearance of new species is a result of the contradictory interaction between the opposed external and internal tendencies.
Consequences for strengthening of health. According to the elaborated conception, a vital capacity and resistance to stress of living beings is connected with the balance between renovating and destructive processes. The higher positive balance--the higher viability, or better health. Therefore, the basic approach to (prophylactic) improvement of people's health consists in strengthening of the self-renovation process. This process is initiated by means of optimal external influences. Efforts of individuals are also necessary, because self-renovating processes, being a kind of coupled ones, proceed only due to expenditure of free energy. Various helpful useful external influences are used by people for this purpose: physical, or mechanical (bodily exercise, massage), thermal (tempering, bath, contrast shower), and informational (suggestions and self-suggestions, prayer), etc. (9)
The conducted theoretical investigation is aimed to make a contribution into the comprehension of the difference between animate and inanimate natural systems. Approximately four billion years ago, living systems appeared on Earth and formed the superstructure over the lower organized geochemical systems. The simplest organisms were characterized by availability of the unique mechanism that permitted them to transform actions from the outside world and to return strengthened/ expedient counteraction back into the environment. Giving an energetic profit from this exchange, living beings in fact extracted free energy from the environment and accumulated it. The forms of life, which lost the ability for the active extraction, in the long run were eliminated by natural selection. Using one more unique quality--regular self-renovation, living systems step-by-step complicated and transformed the planetary medium into an environment. The extraordinary complicated human civilization is the top of this process. Both animate and inanimate natural systems of the universe are interrelated by the deepest universal processes and regularities, as we can see in the tables 1-4. This shows unity of nature and allows us to support the opinion that life should be the widespread phenomenon in the cosmos.
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(8.) Kompanichenko, V. N. (1994a). The cycle and meaning of the existence of humankind. Futures, 26, 506-518.
(9.) Kompanichenko, V. N. (1994b). Personal self-organization--the way to flourishing of the humankind. Khabarovsk: RAEN Publisher. (In Russian)
(10.) Kompanicjenko, V. N. (1994c). Laws of magma systems evolution. Geology of Pacific Ocean, 9, 1097-1108.
(11.) Kompanichenko, V. N. (2002a). Life as high-organized form of the intensified resistance to destructive processes. In G. Palyi, C. Zucci, and L. Caglioti (Eds.), Fundamentals of Life, Paris: Elsevier SAS Editions, 111-124.
(12.) Kompanichenko, V. N. (2002b). One more universal factor for the origin of life: strong fluctuations in the medium. In Thanh Van J. Tran (Ed.), Frontiers of Life. Paris: Editions Frontieres (in press).
(13.) Selye, H. (1974). Stress without distress. Philadelphia & New York: J. B. Lippincott Company.
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(15.) Gesteland, R. F. and Atkins, J. F. (Eds.). (1993). The RNA World. Cold Spring, New York: Cold Spring Harbor Laboratory Press.
Vladimir Kompanichenko (Institute for Complex Analysis; 31 Gerasimov Str., Khabarovsk 680021, Russia; firstname.lastname@example.org)
Table 1. Classification of natural systems based on free energy gradient Natural systems Types of Active, possessing excess Passive, do not possess systems of free energy in respect excess of free energy in to the media respect to the media Systems Surroundings Cosmic Stars (and Outer space Black holes, cosmic their gas/dust clouds, associations), asteroids, meteorites active planets Geological Magmatic and Solid Atmosphere, hydrosphere, hydrothermal lithosphere lithosphere, massifs of systems of of planets rocks, stones, crystals active planets Biological Organisms, Geospheres Products of destruction: communities, coal, oil, gas deposits, ecosystems humus Social Different-rank Biosphere Archaeological monuments communities of of past civilizations people Table 2. Structural complication of active systems at the ascending branch of their cycle of existence Stars Magmatic Hydrothermal systems systems Formation of Increase of General tendency more and silica is growth of more complex concentration acidity and atoms from corresponding complication of the simplest with internal structure hydrogen ones progressive of solutions during polymerization during the thermonuclear of magma development of reactions during the post-magmatic evolution of hydrothermal magmatic systems systems Biological Social systems systems Complication of Complication of structure and ties structure and ties in growing during the organisms and transition from the evolving tribal societies to biosphere the planetary human civilization Table 3. Principal differences between spontaneous and non-spontaneous processes Spontaneous processes Non-spontaneous processes Proceed themselves (do not need Proceed only at the expense of an expenditure of energy) energy Proceed along energetic gradient Proceed against energetic gradient (decrease initial gradient) (increase initial gradient) Decrease free energy and Increase free energy and decrease increase entropy entropy Lead to increase of chaos and Promote to increase of level of disorganization in a system organization and order in a system Table 4. The scheme of matter and active systems complication during the evolution of the universe Evolution of Stages of the universe development the universe from chaos to order Big Bang followed Origin of by the Origin of Stars Planetary Systems Evolution Elementary Simple molecules of particles [right arrow] [right arrow] Complex matter Simple atoms (H, He) molecules [right arrow] [right arrow] Complex Polymeric organic atoms macromolecules Evolution Physical evolution Chemical evolution of of matter of matter active systems Stars Magmatic systems Galaxies Hydrothermal Active planets systems (on active planets) Evolution of Evolution of astrophysical active geochemical active systems systems Evolution of Stages of the universe development the universe from chaos to order Origin of Life Origin of Intelligent Life Evolution Proteins, genes, Buildings, of tissues spacecrafts, matter and other paintings and structures of other things organism created by humans Evolution Biological evolution Social evolution of of matter of matter active systems Organisms People Species Settlements Ecosystems Countries Biosphere Humankind Evolution of Evolution of biological active social active systems systems
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|Date:||Mar 22, 2003|
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