Environmental factors and their classification

Abiotic factors (physical and chemical factors of inorganic nature) are temperature, light, radiation, pressure, humidity, salt composition of water, wind, currents, landscape, all these are properties of inorganic nature, which directly or indirectly impact on living organisms.

Biotic (factors of organic nature) - are forms of exposure of living beings to each other. Each organism constantly undergoes direct or indirect influence of other beings, comes into contact with members of its own species and other species - plants, animals, micro-organisms, depends on them and its turn, impacts them.

Anthropogenic factors - forms of the human society activities that change nature as the habitat of other species, or directly influence their living. The scope of human impact on the organic life of the Earth is continuing to grow.

Changes of environmental factors over time can be: 1) regular and periodic - changing the force of impact depending on time of day or season of the year, or rhythm of tides in the ocean, 2) not regular, with no clear frequency, for example, changes in weather conditions in different years, catastrophic events - storms, heavy rains, landslides, etc., and so on; 3) directed during well-known, sometimes lengthy, periods of time, such as during weather cooling or climate warming, overgrowing of ponds, permanent grazing of cattle in the same area, etc. 4) changes of unspecified action - man-made factors, the most dangerous to living organisms and their communities, such as emissions of pollutants. The nature of these factors is uncertain. Usually an organism is not ready to them, the species haven't met with such phenomena. In the process of evolution these factors present a great difficulty for adaption.  This is their main specificity and ecological unfriendliness. Besides, many of these factors can be harmful. They belong to the group of xenobiotics (Greek xenox - strange). The latter include practically all contaminants. Only in a few cases, with respect to such factors, organisms can use mechanisms of so called preadaptations, that is, adaptations which worked out to other factors. For example, resistance of plants to air pollution in some way is contributed by the structures that are favorable for improving drought resistance: heavy ground leaf tissues, availability of vegetable wax, pubescence, fewer stomata and other structures slowing the absorption of substances and, consequently, poisoning of the organism.

Among the environmental factors we can distinguish between resources and conditions. Environmental resources are used and consumed by organisms, thus, reducing their number. These resources include food, water at its deficit, shelters, comfortable places for breeding, etc. Conditions - these are factors to which the organism can adapt, but can not influence on them. The same environmental factor may be a resource for one species and can be a condition for other species.  For example, light - is a necessary energy resource for plants and animals, and for animals with eyesight - is a condition of visual orientation. Water for many organisms can be both a condition of life and a resource.

Any organism adapts to the environment by adjusting its living activity. These adjustments are called adaptations. Adaptation means any change in the structure and functions of organisms, increasing their chances of survival.

The ability to adapt -is a fundamental property of life in general, as it provides the very possibility of existence, ability of organisms to survive and to breed. Adaptations emerge and develop in the course of evolution.

The basic mechanisms of adaptation at the level of the organism are: 1) biochemical - occur in intracellular processes, such as change of the enzymes, or change in their number, 2) physiological - For example, intensification of sweating of some species when the temperature rises, 3) morphological and anatomical - features of body shape and structure relating to habits of life, 4) behavioral - for example, animals search for favorable habitats, create burrows, nests, etc., 5) ontogenetic - Speeding up or slowing down the development of an individual organism leading to survival when conditions change.

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$$$003-011-001$3.3.11.1 Методические указания к практическому занятию №11

{Цель занятия, методические указания к выполнению практического задания, примеры расчетов и задач}

Answer the questions:

1. What is the basic mechanisms of adaptation?

2. Which are the levels of the organism do you know?

3. When do the adaptations develop?

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$$$003-011-002$3.3.11.2 Задания или тестовые вопросы для контроля к занятию №11

{Задания или тесты (при необходимости указать ключ для выбора варианта)}

Give Russian equivalents of the following words and word combinations:

1. resources; 2.conditions; 3.Environment; 4. temperature, 5. light, 6. radiation, 7. pressure, 8. humidity, 9. salt composition of water, 10. wind, 11. currents, 12. landscape, 13.properties, 14. вiotic factors, 15. plants, 16. animals, 17. micro-organisms, 18. аnthropogenic factors, 19. human society activities, 20. Xenobiotics, 21. preadaptations, 22. Adaptations.

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$$$003-012-000$3.3.12 Практическое занятие №12

{Тема, план занятия}