EntranceZones of influence of environmental factors on the body. Biological regression is a process opposite to biological progress. The ability of organisms to adapt to changing environmental conditions.
Adaptation– this is the adaptation of the organism to environmental conditions due to a complex of morphological, physiological, and behavioral characteristics.
Different organisms adapt to different environmental conditions, and as a result, moisture-loving hydrophytes and "dry-bearers" - xerophytes(Fig. 6); plants of saline soils – halophytes; shade tolerant plants ( sciophytes), and requiring full sunlight for normal development ( heliophytes); animals that live in deserts, steppes, forests or swamps are nocturnal or diurnal. Groups of species with a similar relationship to environmental conditions (that is, living in the same ecotopes) are called environmental groups.
Ability to adapt to unfavorable conditions differ in plants and animals. Due to the fact that animals are mobile, their adaptations are more diverse than those of plants. Animals can:
– avoid unfavorable conditions (birds fly to warmer regions due to lack of food and cold in winter, deer and other ungulates wander in search of food, etc.);
– fall into suspended animation – a temporary state in which life processes are so slow that their visible manifestations are almost completely absent (numbness of insects, hibernation of vertebrates, etc.);
– adapt to life in unfavorable conditions (they are saved from frost by their fur and subcutaneous fat, desert animals have adaptations for economical use of water and cooling, etc.). (Fig. 7).
Plants are inactive and lead an attached lifestyle. Therefore, only the last two adaptation options are possible for them. Thus, plants are characterized by a decrease in the intensity of vital processes during unfavorable periods: they shed their leaves, overwinter in the form of dormant organs buried in the soil - bulbs, rhizomes, tubers, and remain in the state of seeds and spores in the soil. In bryophytes, the entire plant has the ability to undergo anabiosis, which can survive for several years in a dry state.
Plant resistance to adverse factors is increased due to special physiological mechanisms: changing the osmotic pressure in cells, regulating the intensity of evaporation using stomata, using “filter” membranes for selective absorption of substances, etc.
Adaptations develop at different rates in different organisms. They arise most quickly in insects, which in 10–20 generations can adapt to the action of a new insecticide, which explains the failures chemical control density of insect pest populations. The process of developing adaptations in plants or birds occurs slowly, over centuries.
Observed changes in the behavior of organisms are usually associated with hidden characteristics that they had, as it were, “in reserve,” but under the influence of new factors they emerged and increased the stability of the species. Such hidden characteristics explain the resistance of some tree species to industrial pollution (poplar, larch, willow) and some weed species to herbicides.
The same ecological group often includes organisms that are not similar to each other. This is due to the fact that to the same environmental factor different types organisms can adapt in different ways.
For example, they experience the cold differently warm-blooded(they are called endothermic, from the Greek words endon - inside and terme - heat) and cold-blooded (ectothermic, from the Greek ektos - outside) organisms. (Fig. 8.)
The body temperature of endothermic organisms does not depend on temperature environment and is always more or less constant, its fluctuations do not exceed 2–4 o even in the most severe frosts and the most intense heat. These animals (birds and mammals) maintain body temperature by internal heat generation based on intensive metabolism. They retain their body heat through warm “coats” made of feathers, wool, etc.
Physiological and morphological adaptations are complemented by adaptive behavior (choosing sheltered places to spend the night, building burrows and nests, group overnight stays with rodents, close groups of penguins keeping each other warm, etc.). If the ambient temperature is very high, then endothermic organisms are cooled due to special devices, for example, by evaporation of moisture from the surface of the mucous membranes of the oral cavity and upper respiratory tract. (For this reason, in hot weather, the dog’s breathing quickens and he sticks out his tongue.)
The body temperature and mobility of ectothermic animals depends on the ambient temperature. In cool weather, insects and lizards become lethargic and inactive. Many species of animals have the ability to choose a place with favorable conditions of temperature, humidity and sunlight (lizards bask on illuminated rock slabs).
However, absolute ectothermism is observed only in very small organisms. Most cold-blooded organisms are still capable of weak regulation of body temperature. For example, in actively flying insects - butterflies, bumblebees, body temperature is maintained at 36–40 o C even at air temperatures below 10 o C.
Similarly, species of one ecological group in plants differ in their appearance. They can also adapt to the same environmental conditions different ways. Thus, different types of xerophytes save water in different ways: some have thick cell membranes, others have pubescence or a waxy coating on the leaves. Some xerophytes (for example, from the family Lamiaceae) emit vapors of essential oils that envelop them like a “blanket”, which reduces evaporation. The root system of some xerophytes is powerful, goes into the soil to a depth of several meters and reaches the groundwater level (camel thorn), while others have a superficial but highly branched one, which allows them to collect precipitation water.
Among the xerophytes there are shrubs with very small hard leaves that can be shed in the driest time of the year (caragana shrub in the steppe, desert shrubs), turf grasses with narrow leaves (feather grass, fescue), succulents(from the Latin succulentus - succulent). Succulents have succulent leaves or stems that store water, and can easily tolerate high air temperatures. Succulents include American cacti and saxaul, which grows in Central Asian deserts. They have a special type of photosynthesis: the stomata open briefly and only at night; during these cool hours, plants store carbon dioxide, and during the day they use it for photosynthesis with closed stomata. (Fig. 9.)
A variety of adaptations to surviving unfavorable conditions on saline soils is also observed in halophytes. Among them there are plants that are able to accumulate salts in their bodies (saltweed, swede, sarsazan), secrete excess salts onto the surface of the leaves with special glands (kermek, tamarix), and “prevent” salts from entering their tissues due to a “root barrier” impenetrable to salts "(wormwood). In the latter case, the plants have to be content with a small amount of water and they have the appearance of xerophytes.
For this reason, one should not be surprised that in the same conditions there are plants and animals that are dissimilar to each other, which have adapted to these conditions in different ways.
1. What is adaptation?
2. How can animals and plants adapt to unfavorable environmental conditions?
2. Give examples of ecological groups of plants and animals.
3. Tell us about the different adaptations of organisms to surviving the same unfavorable environmental conditions.
4. What is the difference between adaptations to low temperatures in endothermic and ectothermic animals?
Habitat is a part of nature that surrounds a living organism and with which it interacts. Any living organism lives in a complex and changing world, constantly adapting to it and regulating its life activity in accordance with these changes. The elements and properties of an organism’s habitat are dynamic and diverse. For example, some substances the body is extremely necessary for life, to others don't care about him, A third may even have a harmful effect on it.
The ability of living organisms to adapt to their environment is called adaptation. Adaptation of an organism to the environment is one of the main properties of life, since this ensures the possibility of existence, survival and reproduction of organisms.
Along with nutrition, movement and reproduction, a mandatory property of any organism is their ability to protect themselves from the effects of adverse environmental factors, regardless of their nature (abiotic or biotic).
Environmental environmental factors can act as:
1) irritants (which provide adaptive changes in physiological and biochemical functions in the body);
2) limiters (causing the impossibility of the organism’s existence under given conditions);
3) modifiers (promote anatomical and morphological changes in the body);
4) signals (indicating changes in other environmental factors).
In the process of adaptation to unfavorable environmental conditions, organisms were able to develop following paths avoiding them.
Active path– a path that helps strengthen resistance and develop regulatory processes that allow all vital functions of the body to be carried out, despite unfavorable external factors. For example, warm-blooded animals - mammals and birds, living in conditions of variable temperatures, maintain a constant temperature within themselves, which is optimal for the passage of biochemical processes in the cells of the body. This active resistance influence of the surrounding external environment requires large energy costs, which must be constantly replenished, as well as special adaptations in the external and internal structure of the body.
The passive path is closely related to the subordination of the vital functions of the body to changes in environmental factors. For example, a lack of heat in the body leads to suppression of vital functions and a decrease in the level of metabolism, which allows for economical use of energy reserves. When environmental conditions sharply deteriorate, organisms of different species can suspend their vital activity and enter a state of so-called hidden life. Some small organisms can dry out completely in the air and then return to active life after being in water. This state of imaginary death is called suspended animation. The transition to a state of deep anabiosis, in which metabolism almost completely stops, significantly expands the survival capabilities of organisms in the most extreme conditions. For example, dried seeds and spores of many plants, when moistened, sprout even after several years. This also applies to small animals. For example, rotifers and nematodes are capable of withstanding temperatures down to minus 2000C in a state of suspended animation. Examples of hidden life are the torpor of insects, the winter dormancy of perennial plants, the hibernation of vertebrates, the preservation of seeds and spores in the soil, and small organisms in drying up reservoirs. Some bacteria and viruses, including pathogenic ones, can remain in an inactive state for an indefinitely long time until favorable conditions arise for their “awakening” and subsequent active reproduction. This is a phenomenon in which there is temporary physiological rest in individual development In some animals and plants, caused by unfavorable environmental factors, is called diapause.
Avoidance of Adverse Effects- this is the development by the body of such life cycles in which the most vulnerable stages of its development are completed during the most favorable periods of the year in terms of temperature and other conditions. The common way for animals to adapt to unfavorable periods is migration . For example, in Kazakhstan, steppe saigas go annually for the winter to the southern semi-deserts with little snow, where winter grasses are more nutritious and accessible due to the dry climate. In summer, the grassland of semi-deserts quickly dries out due to the dry climate; therefore, saigas migrate to wetter northern areas during breeding. Most often, adaptation of a species to its environment is carried out by a certain combination of all three possible ways their devices.
Living organisms, over the course of long evolution, have developed a variety of devices (adaptations) that allow them to regulate metabolism when the ambient temperature changes. This is achieved by: a) various biochemical and physiological changes in the body, which include changes in the concentration and activity of enzymes, dehydration, lowering the freezing point of solutions present in the body, etc.; b) maintaining body temperature at a more stable temperature level than the temperature of the surrounding habitat, which allows maintaining the course of biochemical reactions that has developed for a given species.
Morphological adaptation- this is the presence of such features of the external structure that contribute to the survival and successful functioning of organisms in their usual conditions. An example of such adaptations is that developed in the process of long evolution external structure organisms that live in the aquatic environment. In particular, adaptations for high-speed swimming in many fish, squids and soaring in water in planktonic organisms. Plants that live in the desert are devoid of leaves (instead of wide traditional leaves, they have formed prickly needles), and their structure is best adapted to maximum accumulation and minimal loss of moisture at high temperatures (cacti). The morphological type of adaptation of an animal or plant, in which they have an external form that reflects the way they interact with their environment, called the life form of a species. Moreover, different species can have a similar life form if they lead a similar lifestyle. Examples in this case include a whale (mammal), a penguin (bird), and a shark (fish).
If in an individual individual adaptation to the environment is achieved due to its physiological mechanisms, then it called physiological adaptation.
Physiological regulation may be insufficient to withstand unfavorable environmental conditions. Sometimes prolonged strain on physiological functions (stress) leads to depletion of the body's resources and can lead to negative consequences. Therefore, in many cases, when environmental conditions persistently deviate from the biological optimum, changes in physiological regulation occur that increase its effectiveness and at the same time reduce the overall functional stress of the body. Such changes are also called acclimation . The acclimation of plants, animals and humans is of great ecological importance. Physiological adaptations are manifested in the characteristics of the enzymatic set in the digestive tract of animals, determined by the composition of food. An example is the camel, which is able to provide the body with the required amount of moisture through the biochemical oxidation of its own fat. Or changes in the body of animals and humans due to lack of oxygen. Low partial pressure of oxygen at high altitudes causes the condition hypoxia – oxygen starvation of cells. The body's immediate response to hypoxia is to increase ventilation of the lungs and intensify blood circulation, but this cannot last for a long time, as it requires energy expenditure and additional oxygen supply. In this regard, in different systems The body undergoes restructuring aimed at reducing hypoxic stress and sufficiently supplying tissues with oxygen when its content in the environment is low. First of all, hematopoiesis is stimulated: the number of red blood cells in the blood increases and the relative content of a special form of hemoglobin, which has an increased affinity for oxygen, increases in them. In this regard, the oxygen capacity and oxygen transport function of the blood increase significantly. Then morphological changes occur in the circulatory system: the arteries of the heart and brain expand, the capillary network in the tissues thickens - all this facilitates the delivery of oxygen to the cells. In the cells themselves, due to an increase in the activity of oxidative enzymes, the affinity for oxygen also increases, and at the same time the relative level of temporary oxygen-free energy supply - anaerobic glycolysis - increases. All these processes of acclimation to hypoxia, occurring over several hours or days, help relieve functional stress from the respiratory and circulatory systems.
IN natural conditions the importance of physiological adaptation is associated with natural changes living conditions, this is mainly due to seasonal changes in temperature, humidity, availability of food in habitats, etc. Everyone is well aware of the autumn increase in thermal insulation in many mammals and birds due to molting, the appearance of winter plumage of the body (down, feathers, fur) and the accumulation of subcutaneous fat. During food-free times, the diet and quality of nutrition changes, physiological functions are aimed at economical expenditure of energy. Seasonal migrations of birds and fish are prepared by a complex of physiological and morphological changes and behavioral changes. All these changes are ensured by specific species-specific programs of physiological adaptation. However, the new physiological qualities of the organism acquired during acclimation are not highly stable; when the season changes and when conditions return to optimal, they are lost and are not inherited. This distinguishes acclimation from species-specific genetic adaptation.
If adaptation in a population of organisms (species) is achieved due to the mechanism of genetic variability and heredity, then its called genetic adaptation . Genetic adaptation occurs over a number of generations and is associated with the process of speciation and the emergence of new life forms of organisms.
Adaptive rhythms of life. Due to the axial rotation of the Earth and its movement around the Sun, the development of life on the planet occurred and occurs under conditions of a regular change of day and night, as well as the alternation of seasons. Such rhythmicity, in turn, creates periodicity, that is, repeatability of conditions in the life of most species. At the same time, the action quite naturally changes large number environmental factors: illumination, temperature, humidity, pressure atmospheric air, all weather components. There is a regularity in the repetition of both periods critical for survival and favorable ones. Circadian rhythms adapt organisms to the cycle of day and night. For example, in humans, about a hundred physiological characteristics are subject to the daily cycle: blood pressure, body temperature, heart rate, breathing rhythm, hormone secretion and many others.
Annual rhythms adapt organisms to seasonal changes in conditions. Thanks to this, the most vulnerable processes for many species of reproduction and rearing of young animals occur during the most favorable season. It should be especially emphasized that the main ecological period to which organisms respond in their annual cycles is not a random change in weather, but photoperiod , that is, changes in the ratio of day and night.
It is known that the length of daylight hours changes naturally throughout the year, and this is what serves as a very accurate signal of the approach of spring, summer, autumn and winter. The ability of organisms to respond to changes in day length is called photoperiodism. Plant photoperiodism, the response to the ratio of light (length of day) and dark (length of night) periods of the day, expressed in changes in the processes of growth and development, is associated with the adaptation of ontogenesis to seasonal changes in external conditions. Day length serves as an indicator of the season for plants and an external signal for the transition to flowering or preparation for an unfavorable season. One of the main manifestations of photoperiodism is the photoperiodic flowering reaction. The organ of photoperiod perception is the leaf, in which, as a result of light and dark reactions, a hormonal complex is formed that stimulates flowering. According to the photoperiod that causes flowering, plants are divided into long-day (cereals, etc.), short-day (rice, millet, hemp, soybeans, etc.) and neutral (buckwheat, peas, etc.). Long-day plants are distributed mainly in temperate and subpolar latitudes, while short-day plants are found closer to the subtropics. Photoperiodism significantly affects the formation (tubers, bulbs, heads of cabbage, stems) and physiological (intensity and form of growth, the onset of the dormant period, leaf fall, etc.) processes. Plant species differ in their belonging to one or another photoperiodic group, and varieties and lines differ in the degree of severity of the photoperiodic reaction. This is taken into account when zoning varieties, as well as in light culture and when growing plants in closed ground.
In animals, photoperiodism controls the timing of the mating season, fertility, autumn and spring molting, egg production, etc., and is genetically associated with biological rhythms. Using the photoperiodic reaction, it is possible to control the development of farm animals and their fertility.
Phototropism(from the Greek word tropos - turn, direction) these are growth movements of plant organs in response to the unilateral directed action of any environmental factor. Tropism is a phenomenon of irritability that causes redistribution of phytohormones in plant tissues. As a result of this, cells on one side of the stem, leaf or root grow faster than on the other, and the organ bends from the stimulus ( positive tropism) or from him ( negative). Thus, the seedling bends towards the light source ( phototropism ), the root grows vertically downward under the influence of gravity ( geotropism), plant roots grow towards a more humid environment ( hydrotropism) . Under the influence of touch and friction, the tendrils of climbing plants wrap around the support ( haptotropism ), in poorly aerated soil, the roots of some mangrove trees grow upward towards a source of oxygen ( aerotropism ), pollen tubes grow towards the ovule, which secretes certain chemicals ( chemotropism) . Tropism is an adaptive reaction that allows a plant to make full use of environmental factors or protect itself from their adverse effects.
In the process of evolution, characteristic time cycles have developed with a certain sequence and duration of periods of reproduction, growth, preparation for winter, that is biological rhythms vital activity of organisms in certain environmental conditions. Tidal rhythms. Species of organisms living in the coastal or bottom part of shallow water (littoral zone), into which light penetrates to the bottom, are in conditions of a very complex periodicity of the external environment. Superimposed on the 24-hour cycle of fluctuations in illumination and other factors is the alternation of ebbs and flows. During lunar days(24 hours 50 minutes) there are 2 high tides and two low tides. Twice a month (new moon and full moon) the strength of the tides reaches its maximum value. The life of organisms is subject to this complex rhythm. coastal zone. For example, female fish smeltweed at the highest tide they lay their eggs at the water's edge, rolling them into the sand. When the tide goes out, the caviar remains to mature in it. The hatching of the fry occurs after half a month, coinciding with the time of the next high tide.
In addition to adaptation, plants and animals have developed defensive responses to certain environmental changes and impacts on them. For example, in plants, protection from unfavorable environmental factors can be provided by:
- features of the anatomical structure (formation of a cuticle, crust, thickening of waxy plaque or mechanical tissue, etc.);
- special defense organs (formation of burning hairs, spines);
- motor and physiological reactions;
- production of protective substances (synthesis of resins, phytoncides, phytoalexins, toxins, protective proteins, etc.).
It is known that each organism survives and reproduces only in a specific environment, characterized by a relatively narrow range of temperatures, precipitation, soil conditions, etc. The geographic range of any species corresponds to the geographic distribution of environmental conditions suitable for a given organism (temperature, humidity, light, atmospheric and water pressure).
Therefore, it is important to have information about the essence of the phenomena caused, the connections and dependencies that have developed between organisms, populations, biocenoses and environmental factors. Their theoretical basis constitutes the law of unity of the organism and the environment, according to which, in the opinion
IN AND. Vernadsky, life develops as a result of constant exchange of matter and information based on energy flows in the total unity of the environment and the organisms inhabiting it.
In the process of conjugate evolution, various types plants and animals have developed mutual adaptations to each other, that is co-adaptation
: they are sometimes so strong that living separately in modern conditions They can’t anymore. This is where unity comes into play. organic world. Coadaptation of insect-pollinated plants and
Insect pollinators are an example of mutual adaptations that have historically emerged. In particular, a consequence of joint evolution is the attachment of various groups of animals to certain groups of plants and their places of growth.
When considering the relationship of organisms with the environment, ecology must, first of all, take into account the criteria of survival and reproduction. They mainly determine the ecological chances of persistence of individual species in a given environment or in a particular ecosystem. Currently, the following definitions (concepts) of the environment have emerged (Fig. 3.1).
Environment– it is the space, matter and energy that surrounds organisms and affects them both positively and negatively.
Fig.3.1. Classification of the concept “environment” (N.F. Reimers, 1990)
Natural environment is called a set of natural abiotic ( inanimate nature) and biotic (living nature) factors in relation to plant and animal organisms, regardless of contact with humans.
Built environment it is a natural environment modified by human activity. It includes " quasi-natural environment(cultivated landscapes, agrocenoses and other objects incapable of self-sustaining); " artificial" environment (artificial structures, buildings, asphalt roads in combination with natural elements - soil, vegetation, air, etc.); the human environment – a set of abiotic, biotic and social factors in combination with “quasi-natural” and “arte-natural” environments. In factorial ecology, the habitat and conditions of existence of organisms are distinguished.
There is also a specific spatial understanding of the environment as the immediate surroundings of the organism - habitat. It includes only those elements of the environment with which a given organism enters into direct and indirect relationships, that is, everything that surrounds it.
Each organism reacts to its environment in accordance with its genetic constitution. Matching Rule environmental conditions of the genetic predetermination of the organism says: “ As long as the environment surrounding a certain type of organism corresponds to the genetic capabilities of this species to adapt to its fluctuations and changes, this species can exist.” According to this rule, one or another species of living things arose in a certain environment and, to one degree or another, was able to adapt to it. Its further existence is possible only in it or in a close environment. A sharp and rapid change in environmental conditions can lead to the fact that the genetic apparatus of a species will not be able to adapt to new living conditions. This can fully be applied to humans. Each organism reacts to its environment in accordance with its genetic constitution.
Adaptation. The visible ability of the body to adapt to the external environment and lifestyle. The process of achieving such compliance.
Analog. Cm. Digital.
Brownian motion. Constant zigzag and unpredictable movement of particles under the influence of molecular impacts.
Genetics. In the strict sense of the word, genetics is a science that studies all aspects of heredity and variability of organisms, as well as the processes of growth and differentiation occurring within them.
Genotype. A set of recipes and instructions that represent a hereditary contribution to the determination of the phenotype (see Dictionary).
Flexibility. Cm. Stress.
Homology. Formal similarity between two organisms in which the relationship between certain parts of A is similar to the relationship between corresponding parts of B. Such formal similarity is considered evidence of an evolutionary relationship.
Idea. In the epistemology proposed in this book, the smallest element of intelligent process is difference, discrimination, or communication of difference. What is called idea in everyday speech, is apparently a complex set of such elements. But in everyday speech it is unlikely to be called idea bilateral symmetry frogs or a signal from a separate nerve impulse.
Information. Any difference that matters.
Cybernetics. Branch of mathematics dealing with problems of control, recursiveness and information.
Coevolution. A stochastic system of evolutionary change in which two or more species interact with each other in such a way that changes in type A create the conditions for natural selection of changes in type B. Subsequent changes in type B, in turn, create conditions for further selection of corresponding changes in the form of A.
Linear. In a mathematical sense linear(linear) is a technical concept that expresses a relationship between variables that is represented by a straight line on a graph in rectangular Cartesian coordinates. In a cybernetic sense linear(lineal) means a relationship between a series of causes or arguments such that the sequence never returns to its starting point. The opposite of mathematical linearity is nonlinearity. The opposite of cybernetic linearity is recursiveness.
Boolean types. Here are some examples:
1. A name is not an object that is called by that name. It belongs to another logical type, higher than the one to which this object itself belongs.
2. The class belongs to a different, higher logical type than the members of this class.
3. The instructions or control emanating from the home thermostat control setting are of a higher logical type than the control provided by the thermometer associated with the thermostat. (A regulator is a device on the wall that is adjusted so that it determines the limits within which the temperature in the room will fluctuate.)
4.Word Tumbleweed is of the same logical type as bush And tree. It is not the name of a plant species or genus; is the name of a class of plants, all members of which have a specific pattern of growth and seed dispersal.
5. Acceleration belongs to a higher logical type than speed.
Mutation. According to traditional evolutionary theory, offspring may differ from their parents as a result of:
1.Changes in DNA called mutations.
2. Recombination of genes during sexual reproduction.
3. Somatic changes that have occurred during the life of the organism as a result of external pressure, habits, age and other factors.
4. Somatic segregation, that is, the loss or rearrangement of genes during epigenesis, leading to the fact that some parts of the body’s tissues acquire a different genetic structure. Genetic changes always have a discrete (see Dictionary) character, but modern theory gives preference (for good reasons) to the point of view that evolution generally consists of small changes. It is assumed that many small mutational changes, cumulative over many generations, lead to larger evolutionary divergences.
Negentropy. Cm. Entropy.
Ontogenesis. The process of development of an individual organism; embryology plus any changes imposed by changes in external conditions and habits.
Parallax. Visibility movement of the observed object, which occurs when the observer's eye moves relative to this object; the difference between the apparent positions of an object when perceived by one or the other eye.
Prochronism. A general pattern contained in the shapes of organisms that indicates their previous growth. Prochronism relates to ontogeny in the same way as homology (see Glossary) relates to phylogeny.
Reductionism. The goal of every scientist is to find the simplest, most parsimonious, and (usually) most elegant explanation of known data. But reductionism becomes harmful if it is carried out by overly insisting that the simplest explanation is the only one. It may be that the data need to be understood within a broader gestalt.
Accident. The sequence of events is called random, if there is no way to predict the next event of this sequence based on previous events, and if the system obeys the laws of probability. Please note that the events we call random, always belong to some limited set. If you toss a coin fairly, the result is called random. With each toss, the probability that the next toss will be heads or tails does not change. But randomness exists within a limited set. Either heads or tails; other possibilities are not considered.
Somatic. (From Greek soma- body). ABOUT somatic the origin of a certain property is said in cases where they want to emphasize that this property arose as a result of bodily changes that appeared during the life of the organism under the influence of external influences or the organism’s own behavior.
Stochastic.(From Greek stochazein- shoot at a target with a bow; that is, to distribute events somewhat randomly, but sometimes with some preferred outcome). If in a sequence of events the element of chance is combined with selectivity, so that only certain outcomes are possible, then such a sequence is called stochastic.
Stress. Lack of entropy, a condition that occurs when the external environment or internal disease places excessive or conflicting demands on the body's ability to adapt. The body doesn't have enough flexibility, which he needs, since he has already used up all the possibilities available to him.
Tautology. A set of statements related to each other, in which the truth connections between the statements is beyond doubt. The truth of these statements themselves is not asserted. Example: Euclidean geometry.
Sacrament. External visible manifestation of internal and spiritual grace.
Taxon. A unit or group used in the classification of animals and plants (for example, species, genus, family).
Topology. A branch of mathematics that does not consider quantitative quantities and deals only with formal relationships between components, especially those that can be represented geometrically. Topology deals with properties (for example, the surface of a body) that are preserved under quantitative distortions.
Phenocopy. A phenotype (see Glossary) having some common features with other phenotypes in which these traits are caused by genetic factors. IN phenocopies these traits appear as a result of somatic changes under environmental pressure.
Phenotype. A set of sentences that make up a description of a real organism; appearance and features of a real organism. Cm. Genotype.
Phylogenesis. History of the evolution of the species.
Digital. The signal is called digital, if it is abruptly separated from other signals from which it must be distinguished. Examples of digital signals - Yes And No. The signal is called analog, when its strength or intensity is used to represent a continuously changing quantity.
Eidetic. The mental image is called eidetic, if it has all the properties of a perceived object, especially if it belongs to a sense organ and therefore appears to come from without.
Energy. In this book the word energy I use to mean quantities, having the dimension of mass multiplied by the square of speed ( MV 2 ). Other people, even physicists, use the word in many other ways.
Entropy. The degree of confusion, disorder, undifferentiation, unpredictability and randomness (see Dictionary) in the relationships between the components of a certain aggregate. Entropy with the opposite sign is called negentropy and expresses the degree of order, differentiation and predictability in a certain aggregate. In physics, some types of order are related to the amount of energy available.
Epigenesis. The process of embryology, considered as related at each stage to status quo ante*.
Epistemology. A section of science, and at the same time a section of philosophy. As a science, epistemology is the study of processes cognition, thinking And decision making individual organisms or their aggregates. As a philosophy, epistemology is the study of the inevitable limitations and other features of the processes of cognition, thinking, and decision-making.
Biological regression- this is an evolutionary movement in which a reduction in habitat occurs; reduction in the number of individuals due to inability to adapt to the environment; a decrease in the number of species in groups due to pressure from other species, the extinction of a species. The science of paleontology has proven that many species in the past completely disappeared. If, with biological progress, some species develop and spread widely throughout to the globe, then during biological regression species disappear, unable to adapt to environmental conditions.
Causes of biological regression: the disappearance of the ability of organisms to adapt to changes in environmental conditions.
The following are subject to biological regression:
2. Animals leading a sedentary lifestyle.
3. Animals living underground or in caves.
2. Examples of degeneration in organisms leading a sedentary lifestyle.
In animals leading a sedentary lifestyle, the organ of movement functions only during the larval stage; the notochord is reduced. For example, the only representative of a separate type of brachiata - pogonophora - lives on the bottom of the sea and leads a sedentary lifestyle. In 1949, zoologist A.V. Ivanov first found it in the Sea of Okhotsk at a depth of 4 km; it was caught in a net along with fish. The elongated worm-like body of the animal is covered with a cylindrical tube. In the front of the body there are tentacles that periodically extend from the tube to the outside for breathing. The body consists of three sections, in the anterior section there are tentacles (in some species there are up to 200-250), a brain, a heart, and excretory organs. The second section is larger, the third is very long. In the inner part of the sections there are respiratory organs, in the outer part there are outgrowths attached to the tube (Fig. 34).
Rice. 34. Pogonophora: 1 tentacles; 2- head; 3-first section of the body; 4-second body section; 5-third body section; 6-sensitive hairs; 7-back of the body
Pogonophora has a brain and heart, but the mouth and stomach are reduced, and the respiratory organs are the tentacles. Due to their sedentary lifestyle, they do not look like animals. In the inner part of the tentacles there are long thin hairs that are equipped with blood vessels. In the water, the hairs come out of the tube and microorganisms attach to them. When there are a lot of them, the pogonophores pull the hairs inside. Under the influence of enzymes, small organisms are digested and absorbed by internal outgrowths.
The rudimentary intestine in the Pogonophora embryo proves the presence of digestive organs in the ancestors. Due to the digestion process outside the body, the digestive organs of pogonophora were reduced.
The structure of the ascidian is also simplified in the process of evolution due to its sedentary lifestyle. Ascidia belongs to one of the branches of the chordate type - tunicates that live in the sea (Fig. 35).
Rice. 35. Ascidians
The sac-like body of the ascidian is covered with a shell, its sole is attached to the bottom of the sea and leads a motionless lifestyle. There are two holes in the upper part of the body, through the first hole water passes into the stomach, and from the second it comes out. Respiratory organs - gill slits. Reproduces by laying eggs. From the egg, mobile tadpole-like larvae with notochord characteristics develop. As an adult, the ascidian attaches to the bottom of the sea, and the body becomes simpler. It is believed that the ascidian is a highly degraded chordate animal.
3. Examples of degeneration of animals living underground or in caves.
In the caves former Yugoslavia and Southern Austria is inhabited by Proteus from the class
amphibians, similar to newt (Fig. 36).
Rice. 36. Proteus
In addition to lungs, it has external gills on both sides of its head. In water, proteas breathe with gills, and on land with lungs. Inhabitants of waters and deep caves, they are serpentine-shaped, transparent, colorless, without pigments. In adults, the eyes are covered by skin, while the larvae have rudimentary eyes. Thus, the ancestors of ascidians had eyes and led a terrestrial lifestyle. In cave organisms, organs of vision and pigments disappeared, and activity decreased.
In flowering plants that transferred to an aquatic environment, the leaf blades became narrow, thread-like, and the conducting tissues stopped developing. The stomata have disappeared, only the flowers have not changed (water buttercup, duckweed, hornwort).
The genetic basis of evolutionary changes leading to simplification of the level of organization is mutation. For example, if the remaining underdeveloped organs - rudiments, albinism (lack of pigments) and other mutations - do not disappear during the process of evolution, then they are found in all members of a given population.
Thus, there are three directions in the evolution of the organic world. Aromorphosis- increasing the level of organization of living organisms; idioadaptation- adaptation of living organisms to environmental conditions without fundamental restructuring of them biological organization;degeneration- simplification of the level of organization of living organisms, leading to biological regression.
The relationship between the directions of biological evolution. The connection between aromorphosis, idioadaptation and degeneration in the evolution of the organic world is not the same. Aromorphosis occurs less frequently than idioadaptation, but it marks a new stage in the development of the organic world. Aromorphosis leads to the emergence of new highly organized systematic groups that occupy a different habitat and adapt to living conditions. Even evolution follows the path of idioadaptation, sometimes degeneration, which provides organisms with a new habitat for them.
Biological regression
Biological regression- decrease in the number of species, narrowing of the range, decrease in the level of adaptability to environmental conditions.
1.What is the difference between biological regression and biological progress?
2. How many pathways does degeneration have?
3. Give examples of degeneration in animals.
4. What are examples of degeneration in plants?
How do you explain the reasons for the disappearance of the roots and leaves of the dodder?
What and how does dodder eat? Does it form organic matter?
1. Explain the reasons for the transformation of broomrape leaves into scales.
2. Analyze examples of degeneration of pogonophorans leading a sedentary lifestyle.
3. How do pogonophorans digest food if they do not have a digestive organ?
4. What organisms do you know that lead a sedentary lifestyle? Describe them.
Where does Proteus live? Explain with examples of degeneration. Give examples of degeneration in plants living in an aquatic environment. Write a short essay about aromorphosis, idioadaptation, degeneration.
Levels of adaptation of the body to changing conditions. How do organisms adapt to environmental conditions? There are several levels at which this process occurs. The cellular level is one of the most important.
Let us consider as an example how it adapts to environmental conditions single cell organism- Escherichia coli. It is known that it grows and reproduces well in a medium containing the only sugar - glucose. When living in such an environment, its cells do not need the enzymes needed to convert other sugars, such as lactose, into glucose. But if bacteria are grown in a medium containing lactose, then intensive synthesis of enzymes that convert lactose into glucose immediately begins in the cells (remember § 17). Consequently, E. coli is able to rearrange its vital activity in order to adapt to new environmental conditions. The above example applies to all other cells, including cells of higher organisms.
Another level at which organisms adapt to environmental conditions is the tissue level. Training leads to the development of tissues and organs: weightlifters have powerful muscles; people who scuba dive have highly developed lungs; Excellent shooters and hunters have special visual acuity. Many qualities of the body can be developed to a large extent by training. For some diseases, especially when huge pressure falls on the liver, a sharp increase in its size is observed. Thus, individual organs and tissues are able to respond to changing living conditions.
Self-regulation. The body is a complex system capable of self-regulation. Self-regulation allows the body to effectively adapt to environmental changes. The ability for self-regulation is highly expressed in higher vertebrates, especially in mammals. This is achieved thanks to the powerful development of the nervous, circulatory, immune, endocrine and digestive systems.
Changing conditions inevitably entail a restructuring of their work. For example, a lack of oxygen in the air leads to intensification of the circulatory system, the pulse quickens, and the amount of hemoglobin in the blood increases. As a result, the body adapts to changed conditions.
Constancy internal environment under systematically changing environmental conditions, it is created by the joint activity of all body systems. In higher animals this is expressed in maintaining a constant body temperature, constant chemical, ionic and gas composition, blood pressure, respiratory rate and heart rate, constant synthesis of necessary substances and destruction of harmful ones.
Maintaining a relative constancy of the internal environment of the body is called homeostasis. Homeostasis - most important property whole organism.
Metabolism - required condition and a way to maintain the stability of the organization of living things. Without metabolism, the existence of a living organism is impossible. The exchange of substances and energy between the body and the external environment is an integral property of living things.
The immune (protective) system plays a special role in maintaining the constancy of the internal environment. The Russian scientist I. I. Mechnikov was one of the first biologists to prove its enormous importance. Cells of the immune system synthesize special proteins - antibodies, which detect and destroy everything foreign to a given organism.
The influence of external conditions on early development organisms. The ability to self-regulate and resist harmful environmental influences does not arise immediately in organisms. During embryonic and postembryonic development, when many protective systems have not yet been formed, organisms are especially vulnerable to the action of damaging factors. Therefore, in both animals and plants, the embryo is protected by special membranes or by the mother’s body itself. It is either equipped with special nourishing tissue or receives nutrients directly from the mother's body. Nevertheless, changes in external conditions can accelerate the development of the embryo or slow it down and even cause various disorders.
Parental use of alcohol, drugs, and smoking tobacco has a harmful effect on the development of the human embryo. Alcohol and nicotine inhibit cellular respiration. Insufficient oxygen supply leads to the fact that fewer cells are formed in the developing organs, and the organs are underdeveloped. Nerve tissue is especially sensitive to lack of oxygen. The future mother's use of alcohol, drugs, smoking tobacco, and drug abuse often lead to irreversible damage to the embryo and the subsequent birth of children with mental retardation or congenital deformities. No less dangerous for the development of the embryo is pollution of the environment by various chemicals or exposure to ionizing radiation.
During the postembryonic period, developing organisms are also very sensitive to harmful environmental influences. This is explained by the fact that the formation of systems for maintaining homeostasis continues after birth. Therefore, alcohol, nicotine, and drugs, which are poisons for the adult body, are especially dangerous for children. These substances inhibit the growth and development of the entire organism, and especially the brain, which leads to mental retardation, serious illnesses and even death.
The biological clock. Organisms do not always strictly maintain the characteristics of their internal environment at the same level. Often external changes entail a restructuring of the internal environment. An example of this is the change in the physiological state of organisms depending on changes in day length throughout the year, or, as they say, changes in photoperiodic conditions.
For many animals and plants living in temperate climates, the breeding season coincides with increasing daylight hours. Changes in photoperiodic conditions in this case are the leading factor. Seasonal rhythms are most clearly manifested in the change of cover of trees in deciduous forests, the change in the plumage of birds and the hair of mammals, in the periodic stops and resumption of plant growth, etc.
The study of the phenomena of daily, seasonal and lunar periodicity in living organisms has shown that all eukaryotes (unicellular and multicellular) have a so-called biological clock. In other words, organisms have the ability to measure daily, lunar, and seasonal cycles.
It is known that tidal currents in the ocean are caused by the influence of the Moon. During the lunar day, the water rises (and recedes) either twice or once, depending on the region of the Earth. Marine animals living in such periodically changing conditions are able to measure the time of high and low tides using biological clocks. Locomotor activity, oxygen consumption and many physiological processes in crabs, sea anemones, hermit crabs and other inhabitants of coastal areas of the seas naturally change during the lunar day.
The course of the biological clock can be restructured depending on changed conditions. An example of such a process is a change in the rhythms of many physiological functions: body temperature, blood pressure, phases of motor activity and rest in a person who has flown from Moscow to Kamchatka, where the Sun rises 9 hours earlier. When flying quickly over long distances, the adjustment of the biological clock does not occur immediately, but over several days.
The daily rhythms of life of many organisms are determined by the alternation of light and darkness: the beginning of dawn or dusk. An hour before sunset, starlings gather in flocks for 10-30 minutes and fly away to roosting sites tens of kilometers away. They are never late thanks to their biological clock, which adjusts to the Sun. In general, daily periodicity results from the coordination of many rhythms, both internal and external.
In some cases, the cause of periodic fluctuations in the internal environment lies in the body itself. Experiments on animals have shown that under conditions of absolute darkness and sound insulation, periods of rest and wakefulness alternate sequentially, falling within a period of time close to 24 hours.
So, fluctuations in the characteristics of the internal environment of the body can be considered as one of the factors that maintain its constancy.
Anabiosis. Often organisms find themselves in environmental conditions in which the continuation of normal life processes is impossible. In such cases, some organisms may fall into suspended animation (from the Greek “ana” - again, “bios” - life), i.e. a condition characterized by a sharp decrease or even temporary cessation of metabolism. Anabiosis is an important adaptation of many species of living beings to unfavorable living conditions. Microbial spores, plant seeds, animal eggs are examples of an anabiotic state. In some cases, suspended animation can last hundreds or even thousands of years, after which the seeds do not lose their viability. Deep freezing of sperm and eggs of especially valuable farm animals for their long-term storage and subsequent widespread use is an example of the use of suspended animation in human practice.
- Give examples confirming the adaptability of organisms to environmental conditions at the cellular and tissue levels.
- Why are alcohol, nicotine, and drugs especially harmful to the embryo?
- Do you think the ability of organisms to measure time and fall into a state of suspended animation can be considered examples of self-regulation? Justify your answer.
- How do you think we can use knowledge about the biological clock and suspended animation in practical activities?