Anatomical adaptations in animals. Behavioral adaptations of organisms to the action of environmental factors. Examples. Warning or threatening coloring

Reactions to unfavorable environmental factors are detrimental to living organisms only under certain conditions, but in most cases they have adaptive significance. Therefore, these responses were called “general adaptation syndrome” by Selye. In later works, he used the terms “stress” and “general adaptation syndrome” as synonyms.

Adaptation is a genetically determined process of the formation of protective systems that ensure increased stability and the course of ontogenesis in unfavorable conditions for it.

Adaptation is one of the most important mechanisms that increases the stability of a biological system, including a plant organism, in changed conditions of existence. The better an organism is adapted to a certain factor, the more resistant it is to its fluctuations.

The genotypically determined ability of an organism to change metabolism within certain limits depending on the action of the external environment is called reaction norm. It is controlled by the genotype and is characteristic of all living organisms. Most modifications that occur within the normal range of reaction have adaptive significance. They correspond to changes in the environment and provide better plant survival under fluctuating conditions environment. In this regard, such modifications have evolutionary significance. The term “reaction norm” was introduced by V.L. Johannsen (1909).

The greater the ability of a species or variety to be modified in accordance with the environment, the wider its reaction rate and the higher its ability to adapt. This property distinguishes resistant varieties of crops. As a rule, slight and short-term changes in environmental factors do not lead to significant violations physiological functions plants. This is due to their ability to maintain relative dynamic balance of the internal environment and the stability of basic physiological functions in a changing external environment. At the same time, sudden and prolonged impacts lead to disruption of many functions of the plant, and often to its death.

Adaptation includes all processes and adaptations (anatomical, morphological, physiological, behavioral, etc.) that contribute to increased stability and contribute to the survival of the species.

1.Anatomical and morphological devices. In some representatives of xerophytes, the length of the root system reaches several tens of meters, which allows the plant to use groundwater and not experience a lack of moisture in conditions of soil and atmospheric drought. In other xerophytes, the presence of a thick cuticle, pubescent leaves, and the transformation of leaves into spines reduce water loss, which is very important in conditions of lack of moisture.

Stinging hairs and spines protect plants from being eaten by animals.

Trees in the tundra or at high mountain altitudes look like squat creeping shrubs; in winter they are covered with snow, which protects them from severe frosts.

In mountainous regions with large daily temperature fluctuations, plants often have the form of spread out pillows with numerous stems densely spaced. This allows you to maintain moisture inside the pillows and a relatively uniform temperature throughout the day.

In the swamp and aquatic plants a special air-bearing parenchyma (aerenchyma) is formed, which is an air reservoir and facilitates the breathing of plant parts immersed in water.

2. Physiological-biochemical adaptations. In succulents, an adaptation for growing in desert and semi-desert conditions is the assimilation of CO 2 during photosynthesis via the CAM pathway. These plants have stomata that are closed during the day. Thus, the plant preserves its internal water reserves from evaporation. In deserts, water is the main factor limiting plant growth. The stomata open at night, and at this time CO 2 enters the photosynthetic tissues. The subsequent involvement of CO 2 in the photosynthetic cycle occurs during the day when the stomata are closed.

Physiological and biochemical adaptations include the ability of stomata to open and close, depending on external conditions. Synthesis in cells of abscisic acid, proline, protective proteins, phytoalexins, phytoncides, increased activity of enzymes that counteract the oxidative breakdown of organic substances, accumulation of sugars in cells and a number of other changes in metabolism contribute to increasing plant resistance to unfavorable conditions external environment.

The same biochemical reaction can be carried out by several molecular forms of the same enzyme (isoenzymes), with each isoform exhibiting catalytic activity in a relatively narrow range of some environmental parameter, such as temperature. The presence of a number of isoenzymes allows the plant to carry out reactions in a much wider temperature range compared to each individual isoenzyme. This allows the plant to successfully perform vital functions in changing temperature conditions.

3. Behavioral adaptations, or avoidance of an unfavorable factor. An example is ephemera and ephemeroids (poppy, chickweed, crocuses, tulips, snowdrops). They go through their entire development cycle in the spring in 1.5-2 months, even before the onset of heat and drought. Thus, they seem to leave, or avoid falling under the influence of the stressor. Similarly, early ripening varieties of agricultural crops form a harvest before the onset of unfavorable seasonal phenomena: August fogs, rains, frosts. Therefore, the selection of many agricultural crops is aimed at creating early ripening varieties. Perennial plants overwinter in the form of rhizomes and bulbs in the soil under snow, which protects them from freezing.

Adaptation of plants to unfavorable factors is carried out simultaneously at many levels of regulation - from an individual cell to a phytocenosis. The higher the level of organization (cell, organism, population), the larger number mechanisms simultaneously participates in the adaptation of plants to stress.

Regulation of metabolic and adaptation processes inside the cell is carried out using systems: metabolic (enzymatic); genetic; membrane These systems are closely interconnected. Thus, the properties of membranes depend on gene activity, and the differential activity of the genes themselves is under the control of membranes. The synthesis of enzymes and their activity are controlled at the genetic level, while at the same time enzymes regulate nucleic acid metabolism in the cell.

On organismal level new ones are added to the cellular mechanisms of adaptation, reflecting the interaction of organs. In unfavorable conditions, plants create and retain such an amount of fruit elements that are sufficiently provided with the necessary substances to form full-fledged seeds. For example, in the inflorescences of cultivated cereals and in the crowns fruit trees in unfavorable conditions, more than half of the established ovaries may fall off. Such changes are based on competitive relationships between organs for physiologically active substances and nutrients.

Under stress conditions, the processes of aging and falling of the lower leaves sharply accelerate. At the same time, substances needed by plants move from them to young organs, responding to the organism’s survival strategy. Thanks to recycling nutrients Of the lower leaves, the younger ones, the upper leaves, remain viable.

Mechanisms for regeneration of lost organs operate. For example, the surface of a wound is covered with secondary integumentary tissue (wound periderm), a wound on a trunk or branch is healed with nodules (calluses). When the apical shoot is lost, dormant buds awaken in plants and side shoots intensively develop. The regeneration of leaves in the spring instead of those that fell in the fall is also an example of natural organ regeneration. Regeneration as a biological adaptation that provides vegetative propagation plants, root segments, rhizomes, thallus, stem and leaf cuttings, isolated cells, individual protoplasts, is of great practical importance for plant growing, fruit growing, forestry, ornamental horticulture, etc.

The hormonal system also participates in the processes of protection and adaptation at the plant level. For example, under the influence of unfavorable conditions in a plant, the content of growth inhibitors sharply increases: ethylene and abscisic acid. They reduce metabolism, inhibit growth processes, accelerate aging, organ loss, and the plant’s transition to a dormant state. Inhibition of functional activity under stress conditions under the influence of growth inhibitors is a characteristic reaction for plants. At the same time, the content of growth stimulants in tissues decreases: cytokinin, auxin and gibberellins.

On population level selection is added, which leads to the emergence of more adapted organisms. The possibility of selection is determined by the existence of intrapopulation variability in plant resistance to various environmental factors. An example of intrapopulation variability in resistance can be the uneven emergence of seedlings on saline soil and the increase in variation in germination timing with increasing stressors.

A species in the modern concept consists of a large number of biotypes - smaller ecological units that are genetically identical, but exhibit different resistance to environmental factors. Under different conditions, not all biotypes are equally viable, and as a result of competition, only those that best meet the given conditions remain. That is, the resistance of a population (variety) to one or another factor is determined by the resistance of the organisms that make up the population. Resistant varieties include a set of biotypes that provide good productivity even in unfavorable conditions.

At the same time, during long-term cultivation of varieties, the composition and ratio of biotypes in the population changes, which affects the productivity and quality of the variety, often not for the better.

So, adaptation includes all processes and adaptations that increase the resistance of plants to unfavorable environmental conditions (anatomical, morphological, physiological, biochemical, behavioral, population, etc.)

But to choose the most effective adaptation path, the main thing is the time during which the body must adapt to new conditions.

In the event of a sudden action of an extreme factor, the response cannot be delayed; it must follow immediately to avoid irreversible damage to the plant. With prolonged exposure to a small force, adaptive changes occur gradually, and the choice of possible strategies increases.

In this regard, there are three main adaptation strategies: evolutionary, ontogenetic And urgent. The goal of the strategy is efficient use available resources to achieve the main goal - the survival of the body under stress. The adaptation strategy is aimed at maintaining the structural integrity of vital macromolecules and the functional activity of cellular structures, preserving life regulation systems, and providing plants with energy.

Evolutionary or phylogenetic adaptations(phylogeny - the development of a biological species over time) are adaptations that arise during the evolutionary process on the basis of genetic mutations, selection and are inherited. They are the most reliable for plant survival.

In the process of evolution, each plant species has developed certain needs for living conditions and adaptability to the ecological niche it occupies, a stable adaptation of the organism to its habitat. Moisture and shade tolerance, heat resistance, cold resistance and other ecological characteristics of specific plant species were formed as a result of long-term exposure to appropriate conditions. Thus, heat-loving and short-day plants are characteristic of southern latitudes, while less demanding heat-loving and long-day plants are characteristic of northern latitudes. Numerous evolutionary adaptations of xerophyte plants to drought are well known: economical use of water, deep-lying root system, shedding leaves and transition to a dormant state, and other adaptations.

In this regard, varieties of agricultural plants exhibit resistance precisely to those environmental factors against the background of which breeding and selection of productive forms is carried out. If selection takes place in a number of successive generations against the background of the constant influence of some unfavorable factor, then the resistance of the variety to it can be significantly increased. It is natural that the varieties bred at the Research Institute of Agriculture of the South-East (Saratov) are more resistant to drought than the varieties created in the breeding centers of the Moscow region. In the same way, in ecological zones with unfavorable soil-climatic conditions, resistant local plant varieties were formed, and endemic plant species are resistant precisely to the stressor that is expressed in their habitat.

Characteristics of resistance of spring wheat varieties from the collection of the All-Russian Institute of Plant Growing (Semyonov et al., 2005)

In a natural setting, environmental conditions usually change very quickly, and the time during which the stress factor reaches a damaging level is not enough for the formation of evolutionary adaptations. In these cases, plants use not permanent, but stressor-induced defense mechanisms, the formation of which is genetically predetermined (determined).

Ontogenetic (phenotypic) adaptations are not associated with genetic mutations and are not inherited. The formation of this kind of adaptation takes a relatively long time, which is why they are called long-term adaptations. One of these mechanisms is the ability of a number of plants to form a water-saving CAM-type photosynthetic pathway under conditions of water deficiency caused by drought, salinity, low temperatures and other stressors.

This adaptation is associated with the induction of the expression of “inactive” in normal conditions the phosphoenolpyruvate carboxylase gene and the genes of other enzymes of the CAM pathway of CO 2 assimilation, with the biosynthesis of osmolytes (proline), with the activation of antioxidant systems and changes in the daily rhythms of stomatal movements. All this leads to very economical use of water.

In field crops, such as corn, aerenchyma in normal conditions there is no growth. But under conditions of flooding and a lack of oxygen in the tissues of the roots, some of the cells of the primary cortex of the root and stem die (apoptosis, or programmed cell death). In their place, cavities are formed through which oxygen is transported from the aboveground part of the plant to the root system. The signal for cell death is ethylene synthesis.

Urgent adaptation occurs with rapid and intense changes in living conditions. It is based on the formation and functioning of shock defense systems. Shock defense systems include, for example, the heat shock protein system, which is formed in response to a rapid increase in temperature. These mechanisms provide short-term conditions for survival under the influence of a damaging factor and thereby create the prerequisites for the formation of more reliable long-term specialized adaptation mechanisms. An example of specialized adaptation mechanisms is the new formation of antifreeze proteins during low temperatures or the synthesis of sugars during the overwintering of winter crops. At the same time, if the damaging effect of a factor exceeds the protective and reparation capabilities of the body, then death inevitably occurs. In this case, the organism dies at the stage of urgent or at the stage of specialized adaptation, depending on the intensity and duration of the extreme factor.

Distinguish specific And nonspecific (general) plant responses to stressors.

Nonspecific reactions do not depend on the nature of the acting factor. They are the same under the influence of high and low temperatures, lack or excess of moisture, high concentration of salts in the soil or harmful gases in the air. In all cases, the permeability of membranes in plant cells increases, respiration is impaired, the hydrolytic breakdown of substances increases, the synthesis of ethylene and abscisic acid increases, and cell division and elongation are inhibited.

The table presents a complex of nonspecific changes that occur in plants under the influence of various environmental factors.

Changes in physiological parameters in plants under the influence of stress conditions (according to G.V. Udovenko, 1995)

Based on the data in the table, it can be seen that plant resistance to several factors is accompanied by unidirectional physiological changes. This gives reason to believe that an increase in plant resistance to one factor may be accompanied by an increase in resistance to another. This has been confirmed by experiments.

Experiments at the Institute of Plant Physiology of the Russian Academy of Sciences (Vl. V. Kuznetsov and others) showed that short-term heat treatment cotton plants is accompanied by an increase in their resistance to subsequent salinity. And the adaptation of plants to salinity leads to an increase in their resistance to high temperatures. Heat shock increases the ability of plants to adapt to subsequent drought and, conversely, during drought the body's resistance to high temperatures increases. Short-term exposure to high temperatures increases resistance to heavy metals and UV-B irradiation. Previous drought promotes plant survival in salinity or cold conditions.

The process of increasing the body's resistance to this environmental factor as a result of adaptation to a factor of a different nature is called cross adaptation.

To study general (nonspecific) mechanisms of resistance, the response of plants to factors that cause water deficiency in plants: salinity, drought, low and high temperatures, and some others is of great interest. At the level of the whole organism, all plants respond to water deficiency in the same way. Characterized by inhibition of shoot growth, increased growth of the root system, abscisic acid synthesis, and decreased stomatal conductance. After some time, the lower leaves age rapidly and their death is observed. All these reactions are aimed at reducing water consumption by reducing the evaporating surface, as well as by increasing the absorption activity of the root.

Specific reactions- These are reactions to the action of any one stress factor. Thus, phytoalexins (substances with antibiotic properties) are synthesized in plants in response to contact with pathogens.

The specificity or non-specificity of response reactions implies, on the one hand, the attitude of the plant to various stressors and, on the other hand, the specificity of the reactions of plants of different species and varieties to the same stressor.

The manifestation of specific and nonspecific plant responses depends on the strength of stress and the speed of its development. Specific responses occur more often if stress develops slowly, and the body has time to rebuild and adapt to it. Nonspecific reactions usually occur with a shorter and stronger stressor. The functioning of nonspecific (general) resistance mechanisms allows the plant to avoid large energy expenditures for the formation of specialized (specific) adaptation mechanisms in response to any deviation from the norm in their living conditions.

Plant resistance to stress depends on the phase of ontogenesis. The most stable plants and plant organs are in a dormant state: in the form of seeds, bulbs; woody perennials - in a state of deep dormancy after leaf fall. Plants are most sensitive at a young age, since under stress conditions growth processes are damaged first. Second critical period is the period of gamete formation and fertilization. Stress during this period leads to a decrease in the reproductive function of plants and a decrease in yield.

If stressful conditions are repeated and have low intensity, then they contribute to plant hardening. This is the basis for methods of increasing resistance to low temperatures, heat, salinity, and increased levels of harmful gases in the air.

Reliability A plant organism is determined by its ability to prevent or eliminate failures at different levels of biological organization: molecular, subcellular, cellular, tissue, organ, organismal and population.

To prevent disruptions in plant life under the influence of unfavorable factors, the principles of redundancy, heterogeneity of functionally equivalent components, systems for repairing lost structures.

Redundancy of structures and functionality is one of the main ways to ensure system reliability. Redundancy and redundancy have diverse manifestations. At the subcellular level, the redundancy and duplication of genetic material contribute to increasing the reliability of the plant organism. This is ensured, for example, by the double helix of DNA and an increase in ploidy. The reliability of the functioning of a plant organism under changing conditions is also supported by the presence of various messenger RNA molecules and the formation of heterogeneous polypeptides. These include isoenzymes that catalyze the same reaction, but differ in their physicochemical properties and the stability of the molecular structure under changing environmental conditions.

At the cellular level, an example of redundancy is an excess of cellular organelles. Thus, it has been established that a portion of the available chloroplasts is sufficient to provide the plant with photosynthetic products. The remaining chloroplasts seem to remain in reserve. The same applies to the total chlorophyll content. Redundancy is also manifested in the large accumulation of precursors for the biosynthesis of many compounds.

At the organismal level, the principle of redundancy is expressed in the formation and in the laying down at different times of more than is required for the change of generations, the number of shoots, flowers, spikelets, in a huge amount of pollen, ovules, and seeds.

At the population level, the principle of redundancy is manifested in a large number of individuals that differ in resistance to a particular stress factor.

Reparation systems also operate at different levels - molecular, cellular, organismal, population and biocenotic. Repair processes require energy and plastic substances, so repair is possible only if sufficient metabolic rate is maintained. If metabolism stops, repair also stops. In extreme environmental conditions, maintaining respiration is especially important, since it is respiration that provides energy for repair processes.

The restorative ability of cells of adapted organisms is determined by the resistance of their proteins to denaturation, namely the stability of the bonds that determine the secondary, tertiary and quaternary structure of the protein. For example, the resistance of mature seeds to high temperatures is usually due to the fact that, after dehydration, their proteins become resistant to denaturation.

The main source of energy material as a substrate for respiration is photosynthesis, therefore, the energy supply of the cell and the associated repair processes depend on the stability and ability of the photosynthetic apparatus to recover after damage. To maintain photosynthesis under extreme conditions in plants, the synthesis of thylakoid membrane components is activated, lipid oxidation is inhibited, and the ultrastructure of plastids is restored.

At the organismal level, an example of regeneration can be the development of replacement shoots, the awakening of dormant buds when growth points are damaged.

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Identifying limiting factors is of great practical importance. Primarily for growing crops: applying the necessary fertilizers, liming soils, land reclamation, etc. allow you to increase productivity, increase soil fertility, and improve the existence of cultivated plants.

1. What do the prefixes “evry” and “steno” mean in the name of the species? Give examples of eurybionts and stenobionts.

Wide range of species tolerance in relation to abiotic environmental factors, they are designated by adding the prefix to the name of the factor "every. The inability to tolerate significant fluctuations in factors or a low limit of endurance is characterized by the prefix "stheno", for example, stenothermic animals. Small changes in temperature have little effect on eurythermal organisms and can be disastrous for stenothermic organisms. A species adapted to low temperatures is cryophilic(from the Greek krios - cold), and to high temperatures - thermophilic. Similar patterns apply to other factors. Plants can be hydrophilic, i.e. demanding on water and xerophilic(dry-tolerant).

In relation to content salts in the habitat they distinguish eurygals and stenogals (from the Greek gals - salt), to illumination – euryphotes and stenophotes, in relation to to the acidity of the environment– euryionic and stenoionic species.

Since eurybiontism makes it possible to populate a variety of habitats, and stenobiontism sharply narrows the range of places suitable for the species, these 2 groups are often called eury – and stenobionts. Many terrestrial animals living in continental climates are able to withstand significant fluctuations in temperature, humidity, and solar radiation.

Stenobionts include- orchids, trout, Far Eastern hazel grouse, deep-sea fish).

Animals that are stenobiont in relation to several factors at the same time are called stenobionts in the broad sense of the word ( fish that live in mountain rivers and streams that cannot tolerate too high temperatures and low oxygen levels, the inhabitants humid tropics, unadapted to low temperatures and low air humidity).

Eurybionts include Colorado potato beetle, mouse, rats, wolves, cockroaches, reeds, wheatgrass.

1. Adaptation of living organisms to environmental factors. Types of adaptation.

Adaptation ( from lat. adaptation - adaptation ) - this is an evolutionary adaptation of environmental organisms, expressed in changes in their external and internal characteristics.

Individuals that for some reason have lost the ability to adapt, in conditions of changes in the regimes of environmental factors, are doomed to elimination, i.e. to extinction.

Types of adaptation: morphological, physiological and behavioral adaptation.

Morphology is the study of the external forms of organisms and their parts.

1.Morphological adaptation- this is an adaptation manifested in adaptation to fast swimming in aquatic animals, to survival in conditions of high temperatures and lack of moisture - in cacti and other succulents.

2.Physiological adaptations lie in the peculiarities of the enzymatic set in the digestive tract of animals, determined by the composition of the food. For example, inhabitants of dry deserts are able to meet their moisture needs through the biochemical oxidation of fats.

3.Behavioral (ethological) adaptations manifest themselves in the most various forms. For example, there are forms of adaptive behavior of animals aimed at ensuring optimal heat exchange with the environment. Adaptive behavior can manifest itself in the creation of shelters, movements in the direction of more favorable, preferred temperature conditions, and selection of places with optimal humidity or light. Many invertebrates are characterized by a selective attitude towards light, manifested in approaches or distances from the source (taxis). Daily and seasonal movements of mammals and birds are known, including migrations and flights, as well as intercontinental movements of fish.

Adaptive behavior can manifest itself in predators during the hunt (tracking and pursuing prey) and in their victims (hiding, confusing the trail). The behavior of animals is extremely specific in mating season and during feeding of offspring.

There are two types of adaptation to external factors. Passive way of adaptation– this adaptation according to the type of tolerance (tolerance, endurance) consists in the emergence of a certain degree of resistance to a given factor, the ability to maintain functions when the strength of its influence changes.. This type of adaptation is formed as a characteristic species property and is realized at the cellular-tissue level. The second type of device is active. In this case, the body, with the help of specific adaptive mechanisms, compensates for changes caused by the influencing factor in such a way that the internal environment remains relatively constant. Active adaptations are adaptations of the resistant type (resistance) that maintain the homeostasis of the internal environment of the body. An example of a tolerant type of adaptation is poikilosmotic animals, an example of a resistant type is homoyosmotic animals. .

1. Define population. Name the main group characteristics of the population. Give examples of populations. Growing, stable and dying populations.

Population- a group of individuals of the same species interacting with each other and jointly inhabiting a common territory. The main characteristics of the population are as follows:

1. Abundance - the total number of individuals in a certain territory.

2. Population density - the average number of individuals per unit area or volume.

3. Fertility - the number of new individuals appearing per unit of time as a result of reproduction.

4. Mortality - the number of dead individuals in a population per unit of time.

5. Population growth is the difference between birth and death rates.

6. Growth rate - average increase per unit of time.

The population is characterized by a certain organization, the distribution of individuals over the territory, the ratio of groups by sex, age, and behavioral characteristics. It is formed, on the one hand, on the basis of the general biological properties of the species, and on the other, under the influence of abiotic environmental factors and the population of other species.

The population structure is unstable. The growth and development of organisms, the birth of new ones, death from various causes, changes in environmental conditions, an increase or decrease in the number of enemies - all this leads to changes in various ratios within the population.

Increasing or growing population– this is a population in which young individuals predominate, such a population is growing in number or is being introduced into the ecosystem (for example, third world countries); More often, there is an excess of birth rates over deaths and the population size grows to such an extent that an outbreak of mass reproduction may occur. This is especially true for small animals.

With a balanced intensity of fertility and mortality, a stable population. In such a population, mortality is compensated by growth and its number, as well as its range, are kept at the same level . Stable population – is a population in which the number of individuals different ages varies evenly and has the character of a normal distribution (as an example, we can cite the population of Western European countries).

Declining (dying) population is a population in which the mortality rate exceeds the birth rate . A declining or dying population is a population in which older individuals predominate. An example is Russia in the 90s of the 20th century.

However, it also cannot shrink indefinitely.. At a certain population level, the mortality rate begins to fall and fertility begins to increase . Ultimately, a declining population, having reached a certain minimum size, turns into its opposite - a growing population. The birth rate in such a population is gradually increasing in certain moment equalizes mortality, i.e. the population becomes stable for a short period of time. In declining populations, old individuals predominate, no longer able to reproduce intensively. Such age structure indicates unfavorable conditions.

1. Ecological niche of an organism, concepts and definitions. Habitat. Mutual arrangement of ecological niches. Human ecological niche.

Any type of animal, plant, or microbe is capable of normally living, feeding, and reproducing only in the place where evolution has “prescribed” it for many millennia, starting with its ancestors. To designate this phenomenon, biologists borrowed term from architecture - the word “niche” and they began to say that each type of living organism occupies its own ecological niche in nature, unique to it.

Ecological niche of an organism- this is the totality of all its requirements for environmental conditions (the composition and regimes of environmental factors) and the place where these requirements are satisfied, or the entire set of biological characteristics and physical parameters of the environment that determine the conditions of existence of a particular species, its transformation of energy, the exchange of information with the environment and its own kind.

The concept of ecological niche is usually used when using the relationships of ecologically similar species belonging to the same trophic level. The term “ecological niche” was proposed by J. Grinnell in 1917 to characterize the spatial distribution of species, that is, the ecological niche was defined as a concept close to the habitat. C. Elton defined an ecological niche as the position of a species in a community, emphasizing the special importance of trophic relationships. A niche can be imagined as part of an imaginary multidimensional space (hypervolume), the individual dimensions of which correspond to the factors necessary for the species. The more the parameter varies, i.e. The adaptability of a species to a specific environmental factor, the wider its niche. A niche can also increase in the case of weakened competition.

Habitat of the species- this is the physical space occupied by a species, organism, community, it is determined by the totality of conditions of the abiotic and biotic environment that ensure the entire development cycle of individuals of the same species.

The habitat of the species can be designated as "spatial niche".

The functional position in the community, in the pathways of processing matter and energy during nutrition is called trophic niche.

Figuratively speaking, if a habitat is, as it were, the address of organisms of a given species, then a trophic niche is a profession, the role of an organism in its habitat.

The combination of these and other parameters is usually called an ecological niche.

Ecological niche(from the French niche - a recess in the wall) - this place occupied by a biological species in the biosphere includes not only its position in space, but also its place in trophic and other interactions in the community, as if the “profession” of the species.

Fundamental ecological niche(potential) is an ecological niche in which a species can exist in the absence of competition from other species.

Ecological niche realized (real) – ecological niche, part of the fundamental (potential) niche that a species can defend in competition with other species.

By relative position niches of two types are divided into three types: non-adjacent ecological niches; niches touching but not overlapping; touching and overlapping niches.

Man is one of the representatives of the animal kingdom, biological species class of mammals. Despite the fact that it has many specific properties (intelligence, articulate speech, work activity, biosociality, etc.), it has not lost its biological essence and all the laws of ecology are valid for it to the same extent as for other living organisms. The man has his own, inherent only to him, ecological niche. The space in which a person’s niche is localized is very limited. As a biological species, humans can only live within the landmass of the equatorial belt (tropics, subtropics), where the hominid family arose.

1. Formulate Gause's fundamental law. What is a "life form"? What ecological (or life) forms are distinguished among the inhabitants of the aquatic environment?

Both in the plant and animal worlds, interspecific and intraspecific competition is very widespread. There is a fundamental difference between them.

Gause's rule (or even law): two species cannot simultaneously occupy the same ecological niche and therefore necessarily displace each other.

In one of the experiments, Gause bred two types of ciliates - Paramecium caudatum and Paramecium aurelia. They regularly received as food a type of bacteria that does not reproduce in the presence of paramecium. If each type of ciliate was cultivated separately, then their populations grew according to a typical sigmoid curve (a). In this case, the number of paramecia was determined by the amount of food. But when they coexisted, paramecia began to compete and P. aurelia completely replaced its competitor (b).

Rice. Competition between two closely related species of ciliates occupying a common ecological niche. a – Paramecium caudatum; b – P. aurelia. 1. – in one culture; 2. – in a mixed culture

When ciliates were grown together, after some time only one species remained. At the same time, the ciliates did not attack individuals of another type and did not emit harmful substances. The explanation is that the species studied had different growth rates. The fastest reproducing species won the competition for food.

When breeding P. caudatum and P. bursaria no such displacement occurred; both species were in equilibrium, with the latter concentrated on the bottom and walls of the vessel, and the former in free space, i.e., in a different ecological niche. Experiments with other types of ciliates have demonstrated the pattern of relationships between prey and predator.

Gauseux's principle is called the principle exception competitions. This principle leads either to the ecological separation of closely related species or to a decrease in their density where they are able to coexist. As a result of competition, one of the species is displaced. Gause's principle plays a huge role in the development of the niche concept, and also forces ecologists to seek answers to a number of questions: How do similar species coexist? How large must the differences between species be for them to coexist? How can competitive exclusion be avoided?

Life form of the species - this is a historically developed complex of its biological, physiological and morphological properties, which determines a certain response to environmental influences.

Among the inhabitants of the aquatic environment (hydrobionts), the classification distinguishes the following life forms.

1.Neuston(from Greek neuston - capable of swimming) – a collection of marine and freshwater organisms that live near the surface of the water , for example, mosquito larvae, many protozoa, water strider bugs, and among plants, the well-known duckweed.

2. Lives closer to the surface of the water plankton.

Plankton(from the Greek planktos - soaring) - floating organisms capable of making vertical and horizontal movements mainly in accordance with the movement of water masses. Highlight phytoplankton- photosynthetic free-floating algae and zooplankton- small crustaceans, mollusc and fish larvae, jellyfish, small fish.

3.Nekton(from the Greek nektos - floating) - free-floating organisms capable of independent vertical and horizontal movement. Nekton lives in the water column - these are fish, in the seas and oceans, amphibians, large aquatic insects, crustaceans, also reptiles (sea snakes and turtles) and mammals: cetaceans (dolphins and whales) and pinnipeds (seals).

4. Periphyton(from Greek peri - around, about, phyton - plant) - animals and plants attached to stems higher plants and rising above the bottom (molluscs, rotifers, bryozoans, hydra, etc.).

5. Benthos ( from Greek benthos - depth, bottom) - bottom organisms leading an attached or free lifestyle, including those living in the thickness of the bottom sediment. These are mainly mollusks, some lower plants, crawling insect larvae, and worms. The bottom layer is inhabited by organisms that feed mainly on decaying debris.

1. What is biocenosis, biogeocenosis, agrocenosis? Structure of biogeocenosis. Who is the founder of the doctrine of biocenosis? Examples of biogeocenoses.

Biocenosis(from the Greek koinos - common bios - life) is a community of interacting living organisms, consisting of plants (phytocenosis), animals (zoocenosis), microorganisms (microbocenosis), adapted to living together in a given territory.

The concept of “biocenosis” – conditional, since organisms cannot live outside their environment, but it is convenient to use in the process of studying ecological connections between organisms. Depending on the area, the attitude towards human activity, the degree of saturation, usefulness, etc. distinguish biocenoses of land, water, natural and anthropogenic, saturated and unsaturated, complete and incomplete.

Biocenoses, like populations - this is a supraorganismal level of life organization, but of a higher rank.

The sizes of biocenotic groups are different- these are large communities of lichen cushions on tree trunks or a rotting stump, but they are also the population of steppes, forests, deserts, etc.

A community of organisms is called a biocenosis, and the science that studies the community of organisms - biocenology.

V.N. Sukachev the term was proposed (and generally accepted) to denote communities biogeocenosis(from Greek bios – life, geo – Earth, cenosis – community) - This is a collection of organisms and natural phenomena characteristic of a given geographical area.

The structure of biogeocenosis includes two components biotic – community of living plant and animal organisms (biocenosis) – and abiotic - a set of inanimate environmental factors (ecotope, or biotope).

Space with more or less homogeneous conditions, which occupies a biocenosis, is called a biotope (topis - place) or ecotope.

Ecotop includes two main components: climatetop- climate in all its diverse manifestations and edaphotope(from the Greek edaphos - soil) - soils, relief, water.

Biogeocenosis= biocenosis (phytocenosis+zoocenosis+microbocenosis)+biotope (climatope+edaphotope).

Biogeocenoses – these are natural formations (they contain the element “geo” - Earth ) .

Examples biogeocenoses there may be a pond, meadow, mixed or single-species forest. At the level of biogeocenosis, all processes of transformation of energy and matter occur in the biosphere.

Agrocenosis(from the Latin agraris and the Greek koikos - general) - a community of organisms created by man and artificially maintained by him with increased yield (productivity) of one or more selected species of plants or animals.

Agrocenosis differs from biogeocenosis main components. It cannot exist without human support, since it is an artificially created biotic community.

1. The concept of "ecosystem". Three principles of ecosystem functioning.

Ecological system- one of the most important concepts of ecology, abbreviated as ecosystem.

Ecosystem(from the Greek oikos - dwelling and system) is any community of living beings along with their habitat, connected inside complex system relationships.

Ecosystem - These are supraorganismal associations, including organisms and the inanimate (inert) environment that interact, without which it is impossible to maintain life on our planet. This is a community of plant and animal organisms and inorganic environment.

Based on the interaction of living organisms that form an ecosystem with each other and their habitat, interdependent aggregates are distinguished in any ecosystem biotic(living organisms) and abiotic(inert or non-living nature) components, as well as environmental factors (such as solar radiation, humidity and temperature, Atmosphere pressure), anthropogenic factors and others.

To the abiotic components of ecosystems These include inorganic substances - carbon, nitrogen, water, atmospheric carbon dioxide, minerals, organic substances found mainly in the soil: proteins, carbohydrates, fats, humic substances, etc., which enter the soil after the death of organisms.

To the biotic components of the ecosystem include producers, autotrophs (plants, chemosynthetics), consumers (animals) and detritivores, decomposers (animals, bacteria, fungi).

Morphological adaptations involve changes in the shape or structure of an organism. An example of such an adaptation is a hard shell, which provides protection from predatory animals. Physiological adaptations are associated with chemical processes in the body. Thus, the smell of a flower can serve to attract insects and thereby contribute to pollination of the plant. Behavioral adaptation is associated with a certain aspect of an animal’s life. A typical example is a bear's winter sleep. Most adaptations are a combination of these types. For example, blood sucking in mosquitoes is ensured complex combination such adaptations as the development of specialized parts of the oral apparatus adapted to sucking, the formation of search behavior to find a prey animal, as well as the production of special secretions by the salivary glands that prevent the clotting of sucked blood.

All plants and animals constantly adapt to their environment. To understand how this happens, it is necessary to consider not only the animal or plant as a whole, but also the genetic basis of adaptation.

Genetic basis.

In each species, the program for the development of traits is embedded in the genetic material. The material and the program encoded in it are passed on from one generation to the next, remaining relatively unchanged, so that representatives of a given species look and behave almost the same. However, in a population of organisms of any species there are always small changes in the genetic material and, therefore, variations in the characteristics of individual individuals. It is from these diverse genetic variations that the process of adaptation selects those traits or favors the development of those traits that most increase the chances of survival and thereby the preservation of genetic material. Adaptation can thus be thought of as the process by which genetic material increases its chances of persistence in subsequent generations. From this point of view, each species represents a successful way of preserving certain genetic material.

To pass on genetic material, an individual of any species must be able to feed, survive until the breeding season, leave offspring, and then spread them over as wide an area as possible.

Nutrition.

All plants and animals must receive energy and various substances from the environment, primarily oxygen, water and inorganic compounds. Almost all plants use the energy of the Sun, transforming it through the process of photosynthesis. Animals get energy by eating plants or other animals.

Each species is adapted in a certain way to provide itself with food. Hawks have sharp talons for capturing prey, and the location of the eyes in the front of the head allows them to judge the depth of space, which is necessary for hunting while flying at high speed. Other birds, such as herons, have developed long neck and legs. They obtain food by carefully wandering through shallow water and lying in wait for unwary aquatic animals. Darwin's finches, a group of closely related bird species from the Galapagos Islands, provide a classic example of highly specialized adaptation to different feeding patterns. Thanks to one or another adaptive morphological changes, primarily in the structure of the beak, some species became granivorous, others became insectivorous.

Turning to fish, predators such as sharks and barracudas have sharp teeth to catch prey. Others, such as small anchovies and herring, obtain small food particles by filtering seawater through comb-like gill rakers.

In mammals, an excellent example of adaptation to the type of nutrition is the structural features of teeth. The canines and molars of leopards and other felines are exceptionally sharp, which allows these animals to hold and tear the body of their prey. Deer, horses, antelopes and other grazing animals have large molars with wide, ribbed surfaces adapted for chewing grass and other plant foods.

A variety of ways to obtain nutrients can be observed not only in animals, but also in plants. Many of them, primarily legumes - peas, clover and others - have developed symbiotic, i.e. mutually beneficial relationship with bacteria: bacteria convert atmospheric nitrogen into a chemical form available to plants, and plants provide energy to bacteria. Carnivorous plants such as sarracenia and sundew obtain nitrogen from the bodies of insects captured by trapping leaves.

Protection.

The environment consists of living and nonliving components. The living environment of any species includes animals that feed on members of that species. Adaptations of predatory species are aimed at efficient food acquisition; Prey species adapt to avoid becoming prey to predators.

Many potential prey species have protective or camouflage colors that hide them from predators. Thus, in some species of deer, the spotted skin of young individuals is invisible against the background of alternating spots of light and shadow, and white hares are difficult to distinguish against the background of snow cover. Long thin bodies Stick insects are also difficult to see because they resemble twigs or twigs from bushes and trees.

Deer, hares, kangaroos and many other animals have evolved long legs that allow them to escape from predators. Some animals, such as opossums and hog snakes, have even developed a unique behavior called death faking, which increases their chances of survival, since many predators do not eat carrion.

Some types of plants are covered with thorns or thorns that repel animals. Many plants have a disgusting taste to animals.

Environmental factors, in particular climate, often place living organisms in difficult conditions. For example, animals and plants often have to adapt to temperature extremes. Animals escape the cold by using insulating fur or feathers, migrating to warmer climates, or going into hibernation. Most plants survive the cold by entering a state of dormancy, equivalent to hibernation in animals.

In hot weather, the animal cools itself by sweating or frequent breathing, which increases evaporation. Some animals, especially reptiles and amphibians, are able to enter summer hibernation, which is essentially similar to winter hibernation, but is caused by heat rather than cold. Others are simply looking for a cool place.

Plants can maintain their temperature to some extent by regulating the rate of evaporation, which has the same cooling effect as sweating in animals.

Reproduction.

A critical step in ensuring the continuity of life is reproduction, the process by which genetic material is passed on to the next generation. Reproduction has two important aspects: the meeting of opposite-sex individuals to exchange genetic material and the raising of offspring.

Among the adaptations that ensure the meeting of individuals of different sexes is sound communication. In some species, the sense of smell plays an important role in this sense. For example, cats are strongly attracted to the smell of a cat in heat. Many insects secrete the so-called. Attractants are chemical substances that attract individuals of the opposite sex. Flower scents are an effective plant adaptation to attract pollinating insects. Some flowers smell sweet and attract nectar-feeding bees; others smell disgusting, attracting flies that feed on carrion.

Vision is also very important for meeting individuals of different sexes. In birds, the male's mating behavior, his lush feathers and bright colors attract the female and prepare her for copulation. Flower color in plants often indicates which animal is needed to pollinate that plant. For example, flowers pollinated by hummingbirds are colored red, which attracts these birds.

Many animals have developed ways to protect their offspring in the early stages of life. Most adaptations of this kind are behavioral and involve actions by one or both parents that increase the chances of survival of the young. Most birds build nests that are specific to each species. However, some species, such as the cowbird, lay eggs in the nests of other bird species and entrust the young to the parental care of the host species. In many birds and mammals, as well as some fish, there is a period when one of the parents takes great risks, taking on the function of protecting the offspring. Although this behavior sometimes threatens the death of the parent, it ensures the safety of the offspring and the preservation of genetic material.

A number of animal and plant species use a different reproductive strategy: they produce a huge number of offspring and leave them unprotected. In this case, the low chances of survival of an individual growing individual are balanced by the large number of offspring.

Settlement.

Most species have developed mechanisms to remove offspring from the places where they were born. This process, called dispersal, increases the likelihood that offspring will grow up in unoccupied territory.

Most animals simply avoid places where there is too much competition. However, evidence is accumulating that dispersal is driven by genetic mechanisms.

Many plants have adapted to dispersing seeds with the help of animals. Thus, the fruits of the cocklebur have hooks on the surface, with which they cling to the fur of passing animals. Other plants produce tasty, fleshy fruits, such as berries, that are eaten by animals; the seeds pass through the digestive tract and are “sown” intact elsewhere. Plants also use wind to spread. For example, the wind carries the “propellers” of maple seeds, as well as cottonweed seeds, which have tufts of fine hairs. Steppe plants such as tumbleweeds, which acquire a spherical shape by the time the seeds ripen, are driven by the wind over long distances, dispersing seeds along the way.

Above were just some of the most striking examples of adaptations. However, almost every trait of any species is the result of adaptation. All these signs form a harmonious combination, which allows the body to successfully lead its own special way of life. Man in all his features, from the structure of the brain to the shape of the big toe, is the result of adaptation. Adaptive traits contributed to the survival and reproduction of his ancestors, who had the same traits. In general, the concept of adaptation is of great importance for all areas of biology.

These are the optimal proportions of the body, the location and density of hair or feathers, etc. Well known appearance aquatic mammal- dolphin. His movements are easy and precise. The independent speed of movement in water reaches 40 kilometers per hour. The density of water is 800 times higher than the density of air. The torpedo-shaped body shape avoids the formation of turbulence in the water flowing around the dolphin.