The word «Ecology» is derived from the Greek «oikos» — a house, a home, a place of residence and «logos» — a doctrine, a science.
The first one who proposed the term «ecology» was the German biologist Evolutionist Eric Haeckel (1834-1919), who introduced this term in 1866, understood the amount of knowledge about the relationship between the animal and the environment, in front of all — living organisms with which she is in contact.
Now the ecology is understood as the science of the relationship between living organisms with their habitat or the science of the interaction of organic groups with each other and their surrounding environment.
The organism in its environment is under the influence of environmental factors. Environmental factor (ET) is any condition of the medium that directly or indirectly affects the body for at least one of the phases of his life.
All EFs are variable, so organisms are forced to adapt to them all the time.
Ecology is rooted in biology, but it has already emerged from this framework, and is an independent discipline that links physical and biological phenomena and creates a bridge between natural and social sciences. Nowadays, ecology breaks down into a number of scientific disciplines and disciplines, sometimes far from the primary understanding of ecology as a biological science.
The environment is the basic environment for environment: the environment, the environment, and the natural environment, which is characterized by diverse interpretations: 1) the environment is a set of all the conditions surrounding the thing, plant, animal or human and directly or indirectly affecting them; 2) environment (NA) — a collection of abiotic, biotic and social environments that together affect the person (biota) and its vital functions; 3) the natural environment — a collection of abiotic biotic and social environment, which together affect the people.
Ecology has become of practical interest at the dawn of developmenthumanity, because every individual to survive, he had to have some knowledge about the environment surrounding him — the forces of nature, plants and animals.
1 Environmental factors — the components of the natural environment
Actuality of theme. The theme «Ecological factors» is relevant today, because, in the environment of its existence, the organism is under the influence of environmental factors, which at least once per phase of the body of the organism, affect it and we must know what are the factors of the environmental environment, how these factors affect organisms and how organisms adapt to them.
Ecological factor (EF) — any influence on the organism, to which in the latter as a result of addiction there is a device. In the process of evolutionary development, each species of organisms adapts to certain conditions beyond which can not exist. Such conditions are a certain chemical composition of the medium, temperature and light modes, etc. All environmental factors, intertwining, create a complex of conditions in which there are organisms, they are divided into abiotic, biotic and anthropic factors.
2 Biogenic factors
Biogenic (biotic) factors (factors of wildlife): phytogenic (plants), zoo (animals), microgenic (viruses, bacteria, simpler).
R. Dazhou distinguishes between two types of interaction between organisms that inhabit the environment:
— homotopic reactions, that is, the interaction between organisms of one species (beech species interact with each other); These include type reactions
group effect (changes related to the association of animals of the same species),
mass effect (due to overpopulation of the environment at
exceeding optimum), intraspecific competition (exacerbated by
degree of population density);
— heterotypic reactions, in which individuals of different species interact (beech and
hornbeam hornbeam forest); the impact of individuals of one species on the species of another
may be zero (0), favorable (+) or unfavorable (-).
Typically, the following main types of interactions between organisms (species, populations) are distinguished: neutralism, competition, amensalism, parasitism, predation, commensalism, symbiosis (protocooperations, mutaulism). Below is their brief characterization (0 means lack of significant interactions, + means stimulation of life, — means suppression of life).
Neutralism (0 0). Between the interacting species (populations) there is nothing in common, they need different environmental conditions (for example, living in a territory of a hare and a hedgehog).
3 Abiogenic factors
The following climatic factors, such as temperature, humidity, and light, are most important for the existence of living organisms.
The temperature on the earth’s surface depends on the geographic latitude of the terrain and its elevation above sea level. In addition, it changes with the seasons. In this connection, different adaptations to temperature conditions have been developed in animals and plants. In most organisms, the processes of life occur in the temperature range from 4 ° C to + 40-45 ° C. This explains the poverty of life forms in the arctic areas and the tundra.
For each species, an optimal temperature and extreme survival limits are characteristic, in which the processes of life still occur. They developed in the process of selection and adaptation to the conditions of existence. Most marine invertebrates are very sensitive to changes in temperature and withstand its increase to only 30 ° C, and few of them — up to 38 ° C. They inhabit large reservoirs that do not overheat, so they have not developed adaptations to survive at high temperatures. Significantly wider range of endurance to changes in temperature in the inhabitants of small freshwater ponds. They can withstand both freezing and heating up to 41-44 ° C.
The body temperature of many organisms (plants and all animals except birds and mammals) depends on the temperature of the environment, they are called poikilotherm (from the Greek poikilos — variegated, variable). The intensity of life and the pace of development of these organisms depend on the external temperature. For example, a favorable temperature for the development of the meadow butterfly is limited to 25-32 ° C; at temperatures over 35 ° C, individuals are killed at all stages of development, and below 10 ° C development ceases. Know the peculiarities of the development of various organisms at different temperatures is important for the implementation of measures to combat insects — pests of agriculture or carriers of pathogens.
Although the body temperature of poikilotermnyh organisms is determined by the temperature of the environment, but they are able to partly change it. Plants avoid overheating by regulating evaporation by automatically opening and closing the stomach. Animal organisms regulate evaporation through the skin pores and respiratory tract.
Flowers of many plants overnight and in bad weather are closed, which protects them from overcooling.
During intense movement (for example, during a fly), insects temporarily increase the body temperature by several degrees. However, in a state of rest, it equals with the ambient temperature.
In some bulk insects (for example, bees) body temperature is maintained by the method of collective thermoregulation. The body of a single bee has an ambient temperature, and a bee family, in which there are several thousand individuals, allocates so much heat that the temperature in the hive is set to 34-35 ° C, which is necessary for the development of larvae.
The most perfect thermoregulation has appeared only in the higher vertebrates — birds and mammals, providing them with a wide resettlement in all climatic zones. They got the name homoiothermic (grim homoios — similar, similar) organisms.
In homoeothermic animals, body temperature was obtained by changing the oak-based processes that produce heat, as well as devices for cooling. In most mammals, cooling is achieved as a result of the evaporation of sweat from the surface of the skin and moisture from the mucous membranes. The hair cover of mammals and feathers of birds also provide thermoregulation. In the nests of animals (burrows, lagoon) creates a peculiar, most favorable microclimate for them.
In most birds, the temperature is usually about 40 ° C, and in mammals — about 37 ° C, this same temperature is maintained both in conditions of high external temperatures and in the cold. However, in young animals, sometimes the mechanisms of thermoregulation are not yet perfect, and they first need maternal heat. The imperfect mechanisms of thermoregulation in lower mammals — ovipositor and marsupials, whose body temperature still depends on the temperature of the environment.
Humidity. Without water life is impossible. Most plants and animals are water-loving. The inhabitants of arid lands developed a number of adaptations for existence in conditions of water shortage. Plants of steppes and deserts (xerophytes) can have altered leaves (spit in the cactus) or be silly (saxaul). Some have very deep roots (for example, camel spit — up to 16 m). In the feather grass leaves form in tubes, prodichami inside, which contributes to the reduction of evaporation. Steaming is prevented by such devices as dense cuticle, wax plaque, and peeling — hairs on the surface of the leaves.
A special group of xerophytes is succulents, which store water in rainy weather and then slowly spend it during drought. They have fleshy stems and leaves (cacti, agave, young).
Finally, the ephemera plants have a short vegetative period (small asterisks, tulips, poppy seeds, saffron), and in the spring before the arid period, they have time to cure, form seeds, stock nutrients in the onion
One and the same environmental factors have different effects on organisms of different species living together. For some, they may be favorable, for others — no. An important element is the reaction of organisms to the force of influence of the environmental factor, the negative effect of which can occur in the case of excess or lack of dose. Therefore, there is the notion of a favorable dose, or a zone of optimum factor and a zone of pessary (a dose of a factor in which organisms feel depressed).
The range of optimum and pumice zones is a criterion for determining ecological valency — the ability of a living organism to adapt to changes in environmental conditions. Quantitatively, it is expressed in the range of environment within which the species normally exists. The ecological valency of different species differs from each other (the northern deer maintains fluctuations of air temperature from -55 to 25-30oS, and tropical corals die even when the temperature changes by 5-6oC).
By ecological valency, organisms are divided into: stenobiotics — with little adaptability to changes in the environment (orchids, trout, Farrier hazel grouse, deep-sea fish) and eurybions — with great adaptability to environmental changes (Colorado beetle, mice, rats, wolves, cockroaches, cane, pyri ) Within the limits of the eurybionts and stenobionts, depending on the specific factor, the organisms are divided into heuristic and stenotermic (by reaction to temperature), evrygaline and wall-hungry (by reaction to the salinity of the aqueous medium), euprophytes and stenofoty (by reaction to light).
It should be emphasized that in nature environmental factors operate in a complex manner. It is especially important to remember this when assessing the impact of chemical pollutants, when the «subjective» effect (the negative effect of one substance is superimposed on the negative effects of others, which adds the influence of the stress situation, noise, various physical fields — radiation, heat, gravity or electromagnetic) very Changes in the MAC values are given in the reference books. This issue is still poorly understood, but due to the urgency and importance it is in active research in all developed countries.
Ecological studies related to the study of the impact of environmental factors on the existence and development of certain types of organisms. interconnections with the environment, is the subject of the science of aucheology.
The section of bioecology, which studies the conditions for the formation of the structure and dynamics of populations of a species, is called demecology, and a section that explores the associations of populations of different species of plants, animals, microorganisms (biocenoses), ways of their formation and interaction with the environment — the synecology. Within the framework of synecology, phytocenology, or geobotanics (object of study — grouping of plants), biocenology (group of animals) are distinguished.