The main indicators of biogeocenosis

By the nature of the impact

ñ Directly acting – directly affecting the body, mainly on metabolism

ñ Indirectly acting – influencing indirectly, through a change in directly acting factors (relief, exposure, altitude, etc.)

Origin

ñ Abiotic — factors of inanimate nature:

ñ climatic : annual sum of temperatures, average annual temperature, humidity, air pressure

ñ edaphic (edaphogenic) : mechanical composition of the soil, air permeability of the soil, acidity of the soil, chemical composition of the soil

ñ orographic : topography, altitude, steepness and exposure of the slope

ñ chemical : gas composition of air, salt composition of water, concentration, acidity

ñ physical : noise, magnetic fields, thermal conductivity and heat capacity, radioactivity, solar radiation intensity

ñ Biotic – associated with the activities of living organisms:

ñ phytogenic – influence of plants

ñ mycogenic — influence of fungi

ñ zoogenic – influence of animals

ñ microbiogenic — influence of microorganisms

ñ Anthropogenic (anthropic) :

ñ physical : the use of nuclear energy, travel in trains and planes, the impact of noise and vibration

ñ chemical : the use of mineral fertilizers and pesticides, pollution of the Earth’s shells with industrial and transport waste

ñ biological : food; organisms for which a person can be a habitat or source of food

ñ social – related to people’s relationships and life in society

Ticket number 2

1. Biogeocenosis – a system that includes a community of living organisms and a closely related set of abiotic environmental factors within the same territory, interconnected by the circulation of substances and the flow of energy (natural ecosystem). It is a sustainable self-regulating ecological system in which organic components (animals, plants) are inextricably linked with inorganic ones (water, soil). Examples: pine forest, mountain valley. The doctrine of biogeocenosis was developed by Vladimir Sukachev in 1940. In foreign literature, it is of little use. Previously, it was also widely used in German scientific literature. A similar concept is an ecosystem – a system consisting of interconnected communities of organisms of different species and their habitat. Ecosystem is a broader concept referring to any such system. Biogeocenosis, in turn, is a class of ecosystems, an ecosystem that occupies a certain area of u200bu200bland and includes the main components of the environment – soil, subsoil, vegetation cover, and the surface layer of the atmosphere. Most artificial ecosystems are not biogeocenoses. Thus, every biogeocenosis is an ecosystem, but not every ecosystem is a biogeocenosis. To characterize biogeocenosis, two close concepts are used: biotope and ecotope (factors of inanimate nature: climate, soil). Biotope is a set of abiotic factors within the territory occupied by biogeocenosis organisms from other biogeocenoses.

Properties of biogeocenosis

ñ natural, historically established system

ñ a system capable of self-regulation and maintenance of its composition at a certain constant level

ñ the circulation of substances is characteristic

ñ an open system for energy input and output, the main source of which is the Sun

The main indicators of biogeocenosis

ñ Species composition – the number of species living in the biogeocenosis.

ñ Species diversity – the number of species living in a biogeocenosis per unit area or volume.

In most cases, the species composition and species diversity do not quantitatively coincide, and the species diversity directly depends on the area under study.

ñ Biomass – the number of organisms of biogeocenosis, expressed in units of mass. Most often, biomass is divided into:

ñ biomass of producers

ñ consumer biomass

ñ decomposer biomass

ñ Productivity

ñ Sustainability

ñ Ability to self-regulate

2. Life form of plants, biological form, biomorph, appearance of plants (habitus), reflecting their adaptability to environmental conditions. The term was proposed by the Danish botanist E. Warming (1884), who understood it as a form in which the vegetative body of a plant is in harmony with the external environment throughout its life, from seed to death. J. f. also called the unit of ecological classification of plants, which means a group of plants with similar adaptive structures. This similarity is not necessarily related to kinship and is often convergent (for example, cacti and some spurges, which form the J. f. of stem succulents). J. f. depends mainly on the structure of the aboveground and underground vegetative organs of plants and is associated with the rhythm of their development and life span. In the course of the evolution of Zh. f. produced as a result of natural selection in various climatic, soil and biocenotic conditions. J. f. of certain groups of plants reflects their adaptability to spatial distribution and fixation in the territory, to the most complete use of the entire complex of habitat conditions.

Specific Zh. f. of each plant (tree, shrub, liana, cushion plant, stlanets, etc.) changes in its ontogeny. Annual seedlings of spruce or oak do not yet have the form of an evergreen or deciduous tree, which is characteristic of these species in adulthood. The same species under different conditions may have a different life style; and altitudinal boundaries of its distribution are shrubby and creeping forms. Therefore, under J. f. as a classification unit is understood the totality of adults in their normal living conditions.

The first physiognomic classification of the main forms of plants according to their external appearance, which determines the landscape of the area, belongs to the German naturalist A. Humboldt (1806), who identified 19 such forms. Mostly physiognomic were the systems of the “basic forms” of the Austrian botanist A. Kerner (1863), the “plant forms” of the German botanist A. Grisebach (1872), and the life forms of the German taxonomist O. Drude (1913). However, they already emphasized the dependence of plant appearance on climate, the importance of biological characteristics. Subsequently, classifications based on special adaptive features appeared. Of these, the most common and popular classification is Zh. f. Danish botanist K. Raunkner (1905, 1907), based on the position of the renewal buds in relation to the soil surface under adverse conditions (in winter or during a dry period) and the nature of the protective bud covers, i.e., on signs that are easily accessible for observation. Raunkier highlights the trace. 5 types of life forms: phanerophytes – renewal buds high above the ground (trees, shrubs, woody vines, epiphytes); hamefites – low plants with buds located no higher than 20-30 cm above the ground and often wintering under the snow (shrubs, semi-shrubs, some perennial grasses); hemicryptophytes – herbaceous perennials with buds at soil level, protected by snow and leaf waste: cryptophytes – buds are hidden underground (rhizomatous, tuberous, bulbous geophytes) or under water (hydrophytes); therophytes are annuals that endure an unfavorable period in the form of seeds ( Fig. 1 ). For herbaceous plants, the classification of the Soviet botanist G. N. Vysotsky (1915), developed by L. I. Kazakevich (1922), is more often used, in which the nature of underground organs and the ability of plants for vegetative reproduction and area capture are taken as a basis: tap root (no vegetative propagation ), turf, bulbous and bulbous (in these groups, vegetative reproduction is poorly expressed), root shoots (vegetative reproduction is intense). V. R. Williams subdivided J. f. cereals according to the tillering method and the position of the buds into long-rhizome, loose and dense bush.

The Soviet botanist I. G. Serebryakov proposed (1962, 1964) a classification in which the largest subdivisions (departments and types) are distinguished according to the structure and life span of aboveground skeletal axes (trees with a trunk that lives tens and hundreds of years, shrubs – with axes, living 20-30 years, shrubs – 5-10 years, herbs with annual orthotropic shoots). Each type is detailed further on a number of features.

Studying Zh. f. important for solving a number of theoretical and practical issues. So, Raunkier used the percentage of J. f. in the flora of a particular area (“biological spectrum”) to characterize the climate (for example, the climate of phanerophytes – humid tropics, hemicryptophytes – northern temperate and cold zones). Geobotanists study Zh. f. as components of phytocenosis reflecting ecological conditions. In a comprehensive study of edificators (the main species that make up the phytocenosis) of steppe vegetation, the concept of ecobiomorph (E. M. Lavrenko and others) is used, which is somewhat different from Zh. and including also the physiological characteristics of objects. In comparative morphogenetic studies, the goal is to elucidate the course of the formation of life forms. both in ontogenesis and in the phylogenesis of individual systematic groups. Studying of changes Zh. f. under the influence of various environmental factors is very important for work on the introduction of plants and is carried out in a number of botanical gardens.
3. Environmental factors.

Ticket number 3

1.Consortia

2. Dynamics of phytocenoses . Each phytocenosis is not a frozen phenomenon of nature, but a system that is in a state of constant dynamics. The variability of phytocenosis over time is one of its most characteristic features.

Diurnal variability is due to the change of day and night, which is associated with a change in various habitat factors. First of all, lighting conditions change, and with them temperature, humidity, exposure to animals and other factors change. Plants respond to daily changes in environmental conditions by changing the intensity of vital processes. In addition, a number of plant species have daily rhythms in flowering, in the arrangement of leaves or inflorescences. All this leads to minor changes in the appearance and structure of phytocenoses, while the species composition remains unchanged during the day.

Seasonal variability of phytocenoses, as well as daily, is characterized by a strict periodicity. It is due to two reasons – seasonal changes in environmental conditions and the peculiarities of seasonal growth and development of plants. The floristic composition is one of the most stable traits, since it practically does not depend on the phenological development of plants. The composition of vegetative and dormant cenopopulations, the age composition (especially in cenopopulations of annual plants), and the quantitative ratios of cenopopulations change sharply according to the seasons of the year.

Year-to-year changes , also called fluctuations , include longer, compared to seasonal, modifications of phytocenoses. These are changes that take place over several adjacent years and for which the time scale of measurement is one year. Fluctuations, as well as seasonal changes, are reversible and do not lead to a change from one phytocenosis to another. However, in contrast to seasonal variability, fluctuations do not differ in strict periodicity, but take place first in one direction, then in the other direction from some average state of the phytocenosis.

Almost all signs of phytocenoses are subject to fluctuations, but not to the same extent. The floristic composition of the phytocenosis is the most stable; signs of structure, productivity, nature of the phytoenvironment, etc. can fluctuate quite strongly. Herbaceous phytocenoses are subject to sharper year-to-year changes than forest ones. The least susceptible to fluctuations are phytocenoses formed by evergreens.

Fluctuations can be caused by various reasons. The most important role is played by external causes, primarily cyclical changes in climatic and hydrological conditions. So, in wet years, in the same phytocenosis, more moisture-loving species grow stronger, and in dry years, on the contrary, more drought-resistant ones. For phytocenoses of floodplain meadows, the duration of flooding in spring is of great importance. If the floodplain remains under water for a longer period than usual, then hygrophytes and even marsh species begin to play an important role in the herbage. Fluctuations of phytocenoses are so sharp that it seems that one phytocenosis is replaced by another. However, unlike shifts, fluctuations always end in a relatively short time with a return to the original state.

3.Reaction of plants to environmental factors

Ticket number 4

1. Flora – a historically established set of plant species distributed in a specific territory (“flora of Russia”) or in an area with certain conditions (“marsh flora”) at the present time or in past geological epochs. In practice, the expression “Flora of a territory” is often understood not as all the plants of a given territory, but only as vascular plants; plants of other groups, as a rule, are considered separately due to the peculiarities of the method of collection and determination. Indoor plants, plants in greenhouses and other structures with an artificial climate are not part of the flora. The branch of botany concerned with the study of flora is called floristry.

The name of the term comes from the name of the ancient Roman goddess of flowers and spring flowering Flora (lat. Flora ).

The word “flora” in the sense of “a set of plants” was first used by the Polish botanist Michal Boym (1614-1659) in his work Flora of China, published in Vienna in 1656.

The second time this meaning was used by the great Swedish naturalist Carl Linnaeus (1707-1778)

Vegetation (vegetation cover) – a set of phytocenoses of a certain territory or the entire Earth as a whole. Unlike flora, which is characterized only by species composition, vegetation is characterized by both species composition and the number of individuals (both in individual plant taxa and in general for the territory under consideration), and features of the combination of representatives of various plant taxa, and ecological links between them. .

Vegetation is a dynamic system. As a result of changing natural conditions, this system can change significantly in a very short time.

Distinguish between indigenous vegetation (not modified by man) and derived vegetation (that is, modified – for example, as a result of fires and human activities, a significant part of the spaces on which tropical forests grew is now occupied by savannah vegetation.)

Vegetation, which has been preserved unchanged from more ancient eras, is called relic . For example, in tropical rainforests, some formations have existed unchanged in the same place since the Miocene.

2. Year-to-year changes , also called fluctuations , include longer, compared to seasonal, modifications of phytocenoses. These are changes that take place over several adjacent years and for which the time scale of measurement is one year. Fluctuations, as well as seasonal changes, are reversible and do not lead to a change from one phytocenosis to another. However, in contrast to seasonal variability, fluctuations do not differ in strict periodicity, but take place first in one direction, then in the other direction from some average state of the phytocenosis.

Almost all signs of phytocenoses are subject to fluctuations, but not to the same extent. The floristic composition of the phytocenosis is the most stable; signs of structure, productivity, nature of the phytoenvironment, etc. can fluctuate quite strongly. Herbaceous phytocenoses are subject to sharper year-to-year changes than forest ones. The least susceptible to fluctuations are phytocenoses formed by evergreens.

Fluctuations can be caused by various reasons. The most important role is played by external causes, primarily cyclical changes in climatic and hydrological conditions. So, in wet years, in the same phytocenosis, more moisture-loving species grow stronger, and in dry years, on the contrary, more drought-resistant ones. For phytocenoses of floodplain meadows, the duration of flooding in spring is of great importance. If the floodplain remains under water for a longer period than usual, then hygrophytes and even marsh species begin to play an important role in the herbage. Fluctuations of phytocenoses are so sharp that it seems that one phytocenosis is replaced by another. However, unlike shifts, fluctuations always end in a relatively short time with a return to the original state.

3. THE LAW OF COMPENSATION OF FACTORS, the effect of compensation of factors, the law of interchangeability of factors, Ryubel’s law, the law identified by E. Ryubel (1930), according to Krom, the absence or lack of certain environmental. factors can be compensated by some other close (analogous) factor. So, the lack of light in a greenhouse can be compensated either by an increase in the concentration of CO2, or by the stimulating effect of certain biologically active substances (eg, gibberellins). However, such compensation of factors, as a rule, is relative, since the fundamental environmental (physiological) factors (light, water, CO2, nitrogen, phosphorus, potassium, many trace elements, etc.) are in principle irreplaceable (Williams’ law).

Ticket number 5.

1. See ticket number 1 question 1

2. See ticket number 3 question 2

3. Ecological range – a region where a species can live due to the presence of suitable conditions for it, regardless of where this region is located and whether it is separated by barriers that are insurmountable for the species

The law of optimum ( in ecology ) – any environmental factor has certain limits of positive influence on living organisms.

The results of the action of a variable factor depend primarily on the strength of its manifestation, or dosage. Factors positively affect organisms only within certain limits. Insufficient or excessive their action affects organisms negatively.

The optimum zone is the range of the factor that is most favorable for life. Deviations from the optimum define pessimum zones. In them, organisms experience oppression.

The minimum and maximum tolerated values of the factor are the critical points beyond which the organism dies. The favorable force of influence is called the zone of optimum of the ecological factor or simply the optimum for an organism of a given species. The stronger the deviation from the optimum, the more pronounced the inhibitory effect of this factor on organisms ( pessimum zone ).

The law of optimum is universal. It defines the boundaries of the conditions under which the existence of species is possible, as well as the measure of the variability of these conditions. Species are extremely diverse in their ability to tolerate changes in factors. In nature, there are two extreme options – narrow specialization and broad endurance. In specialized species, the critical points of the factor values are very close; such species can live only in relatively constant conditions. So, many deep-sea inhabitants – fish, echinoderms, crustaceans – do not tolerate temperature fluctuations even within 2-3 ° C. Plants of humid habitats (marsh marigold, impatiens, etc.) instantly wither if the air around them is not saturated with water vapor. Species with a narrow hardiness range are called stenobionts, and those with a wide hardiness range are called eurybionts. If it is necessary to emphasize the attitude to any factor, use the combinations “steno-” and “evry-” in relation to its name, for example, a stenothermic species – not tolerant of temperature fluctuations, euryhaline – capable of living with wide fluctuations in water salinity, etc.

Ticket number 6

1. Phytocenosis – a plant community that exists within the same biotope. It is characterized by the relative homogeneity of the species composition, a certain structure and system of relationships between plants with each other and with the external environment. According to N. Barkman, a phytocenosis is a specific segment of vegetation in which internal floristic differences are less than differences with the surrounding vegetation. The term was proposed by the Polish botanist I.K. Pachoski in 1915. Phytocenoses are the object of study of the science of phytocenology (geobotany).

Phytocenosis is a part of biocenosis along with zoocenosis and microbiocenosis. The biocenosis, in turn, in combination with the conditions of the abiotic environment (ecotope) forms a biogeocenosis. Phytocenosis is the central, leading element of biogeocenosis, as it transforms the primary ecotope into a biotope, creating a habitat for other organisms, and is also the first link in the circulation of matter and energy. Soil properties, microclimate, composition of the animal world, such characteristics of biogeocenosis as biomass, bioproductivity, etc. depend on vegetation. In turn, the elements of a phytocenosis are the coenopopulations of plants—collections of individuals of the same species within the boundaries of phytocenoses.

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