Essential features of the ground-air habitat. Ground-air environment of life

A NEW LOOK Adaptations of organisms to living in the ground-air environmentLiving organisms in ground-air environment surrounded by air. The air has a low density and, as a result, a low lifting force, insignificant support and low resistance to the movement of organisms. Terrestrial organisms live in conditions of relatively low and constant atmospheric pressure, also due to low air density.

Air has a low heat capacity, so it heats up quickly and cools down just as quickly. The rate of this process is inversely related to the amount of water vapor it contains.

Light air masses have greater mobility, both horizontally and vertically. This helps to maintain a constant level of the gas composition of the air. The oxygen content in air is much higher than in water, so oxygen on land is not a limiting factor.

Light in conditions of terrestrial habitation, due to the high transparency of the atmosphere, does not act as a limiting factor, in contrast to the aquatic environment.

The ground-air environment has different modes of humidity: from the complete and constant saturation of air with water vapor in some areas of the tropics to their almost complete absence in the dry air of deserts. The variability of air humidity during the day and seasons of the year is also great.

Moisture on land acts as a limiting factor.

Due to the presence of gravity and the lack of buoyancy, the terrestrial inhabitants of the land have well-developed support systems that support their body. In plants, these are various mechanical tissues, especially powerfully developed in trees. Animals have developed both an external (arthropod) and an internal (chordate) skeleton during the evolutionary process. Some groups of animals have a hydroskeleton (roundworms and annelids). Problems in terrestrial organisms with maintaining the body in space and overcoming the forces of gravity have limited their maximum mass and size. The largest land animals are inferior in size and mass to the giants of the aquatic environment (the mass of an elephant reaches 5 tons, and a blue whale - 150 tons).

The low air resistance contributed to the progressive evolution of the locomotion systems of terrestrial animals. So, mammals acquired the highest speed of movement on land, and birds mastered the air environment, having developed the ability to fly.

High mobility of air in vertical and horizontal directions is used by some terrestrial organisms at different stages of their development for settling with the help of air currents (young spiders, insects, spores, seeds, plant fruits, protist cysts). By analogy with aquatic planktonic organisms, as adaptations for passive soaring in the air, insects have developed similar adaptations - small body sizes, various outgrowths that increase the relative surface of the body or some of its parts. Seeds and fruits dispersed by the wind have various pterygoid and paragayate appendages that increase their ability to plan.

The adaptations of terrestrial organisms to the preservation of moisture are also diverse. In insects, the body is reliably protected from drying out by a multilayer chitinized cuticle, the outer layer of which contains fats and wax-like substances. Similar water-saving adaptations are also developed in reptiles. The ability for internal fertilization developed in terrestrial animals made them independent of the presence of an aquatic environment.

The soil is a complex system consisting of solid particles surrounded by air and water.

Depending on the type - clayey, sandy, clayey-sandy and others - the soil is more or less permeated with cavities filled with a mixture of gases and aqueous solutions. In the soil, in comparison with the surface layer of air, temperature fluctuations are smoothed out, and at a depth of 1 m, seasonal temperature changes are also imperceptible.

The uppermost soil horizon contains more or less humus, on which plant productivity depends. The middle layer located under it contains washed out from the top layer and converted substances. The bottom layer is mother breed.

Water in the soil is present in voids, the smallest spaces. The composition of soil air changes dramatically with depth: the oxygen content decreases, and carbon dioxide increases. When the soil is flooded with water or intensive decay of organic residues, anoxic zones appear. Thus, the conditions of existence in the soil are different at its different horizons.

In the course of evolution, this environment was mastered later than the water. Its peculiarity lies in the fact that it is gaseous, therefore it is characterized by low humidity, density and pressure, high oxygen content.

In the course of evolution, living organisms have developed the necessary anatomical, morphological, physiological, behavioral and other adaptations.

Animals in the ground-air environment move through the soil or through the air (birds, insects), and plants take root in the soil. In this regard, animals developed lungs and tracheas, while plants developed a stomatal apparatus, i.e.

organs by which the land inhabitants of the planet absorb oxygen directly from the air. The skeletal organs, which provide autonomy of movement on land and support the body with all its organs in conditions of low density of the medium, thousands of times less than water, have received a strong development.

Environmental factors in the terrestrial-air environment differ from other habitats in high light intensity, significant fluctuations in air temperature and humidity, the correlation of all factors with geographical location, the change of seasons of the year and time of day.

Their impact on organisms is inextricably linked with the movement of air and the position relative to the seas and oceans and is very different from the impact in the aquatic environment (Table 1).

Table 5

Living conditions of air and water organisms

(according to D. F. Mordukhai-Boltovsky, 1974)

air environment

aquatic environment

Humidity	Very important (often in short supply)	Does not have (always in excess)
Density	Minor (except for soil)	Large compared to its role for the inhabitants of the air
Pressure	Has almost no	Large (can reach 1000 atmospheres)
Temperature	Significant (fluctuates within very wide limits - from -80 to + 100 ° С and more)	Less than the value for the inhabitants of the air (fluctuates much less, usually from -2 to + 40 ° C)
Oxygen	Minor (mostly in excess)	Essential (often in short supply)
suspended solids	unimportant; not used for food (mainly mineral)	Important (food source, especially organic matter)
Solutes in the environment	To some extent (only relevant in soil solutions)	Important (in a certain amount needed)

Land animals and plants have developed their own, no less original adaptations to adverse environmental factors: the complex structure of the body and its integument, the frequency and rhythm of life cycles, thermoregulation mechanisms, etc.

Purposeful mobility of animals in search of food developed, wind-borne spores, seeds and pollen of plants, as well as plants and animals, whose life is entirely connected with the air, appeared. An exceptionally close functional, resource and mechanical relationship with the soil has been formed.

Many of the adaptations we have discussed above as examples in the characterization of abiotic environmental factors.

Therefore, it makes no sense to repeat now, because we will return to them in practical exercises

Soil as habitat

Earth is the only planet that has soil (edasphere, pedosphere) - a special, upper shell of land.

This shell was formed in a historically foreseeable time - it is the same age as land life on the planet. For the first time, the question of the origin of the soil was answered by M.V. Lomonosov ("On the layers of the earth"): "... the soil came from the bending of animal and plant bodies ... by the length of time ...".

And the great Russian scientist you. You. Dokuchaev (1899: 16) was the first to call soil an independent natural body and proved that soil is "... the same independent natural-historical body as any plant, any animal, any mineral ... it is the result, a function of the cumulative, mutual activity of the climate of a given area, its plant and animal organisms, the relief and age of the country ..., finally, the subsoil, i.e.

ground parent rocks. ... All these soil-forming agents, in essence, are completely equivalent in magnitude and take an equal part in the formation of normal soil ... ".

And the modern well-known soil scientist N.A.

Kachinsky ("Soil, its properties and life", 1975) gives the following definition of soil: "Under the soil should be understood all the surface layers of rocks, processed and changed by the combined influence of climate (light, heat, air, water), plant and animal organisms" .

The main structural elements of the soil are: the mineral base, organic matter, air and water.

Mineral base (skeleton)(50-60% of the total soil) is an inorganic substance formed as a result of the underlying mountain (parent, soil-forming) rock as a result of its weathering.

Sizes of skeletal particles: from boulders and stones to the smallest grains of sand and silt particles. The physicochemical properties of soils are mainly determined by the composition of parent rocks.

The permeability and porosity of the soil, which ensure the circulation of both water and air, depend on the ratio of clay and sand in the soil, the size of the fragments.

In temperate climates, it is ideal if the soil is formed by equal amounts of clay and sand, i.e. represents loam.

In this case, the soils are not threatened by either waterlogging or drying out. Both are equally detrimental to both plants and animals.

organic matter- up to 10% of the soil, is formed from dead biomass (plant mass - litter of leaves, branches and roots, dead trunks, grass rags, organisms of dead animals), crushed and processed into soil humus by microorganisms and certain groups of animals and plants.

The simpler elements formed as a result of the decomposition of organic matter are again assimilated by plants and are involved in the biological cycle.

Air(15-25%) in the soil is contained in cavities - pores, between organic and mineral particles. In the absence (heavy clay soils) or when the pores are filled with water (during flooding, thawing of permafrost), aeration in the soil worsens and anaerobic conditions develop.

Under such conditions, the physiological processes of organisms that consume oxygen - aerobes - are inhibited, the decomposition of organic matter is slow. Gradually accumulating, they form peat. Large reserves of peat are characteristic of swamps, swampy forests, and tundra communities. Peat accumulation is especially pronounced in the northern regions, where coldness and waterlogging of soils mutually determine and complement each other.

Water(25-30%) in the soil is represented by 4 types: gravitational, hygroscopic (bound), capillary and vaporous.

Gravity- mobile water, occupying wide gaps between soil particles, seeps down under its own weight to the groundwater level.

Easily absorbed by plants.

hygroscopic, or bound– is adsorbed around colloidal particles (clay, quartz) of the soil and is retained in the form of a thin film due to hydrogen bonds. It is released from them at high temperature (102-105°C). It is inaccessible to plants, does not evaporate. In clay soils, such water is up to 15%, in sandy soils - 5%.

capillary- is held around soil particles by the force of surface tension.

Through narrow pores and channels - capillaries, it rises from the groundwater level or diverges from cavities with gravitational water. Better retained by clay soils, easily evaporates.

Plants easily absorb it.

Vaporous- occupies all pores free from water. Evaporates first.

There is a constant exchange of surface soil and groundwater, as a link in the general water cycle in nature, changing speed and direction depending on the season and weather conditions.

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Gas composition of the atmosphere is also an important climatic factor.

Approximately 3-3.5 billion years ago, the atmosphere contained nitrogen, ammonia, hydrogen, methane and water vapor, and there was no free oxygen in it. The composition of the atmosphere was largely determined by volcanic gases.

It was in the terrestrial environment, on the basis of the high efficiency of oxidative processes in the body, that animal homoiothermia arose. Oxygen, due to its constantly high content in the air, is not a factor limiting life in the terrestrial environment. Only in places, under specific conditions, is a temporary deficit created, for example, in accumulations of decaying plant residues, stocks of grain, flour, etc.

For example, in the absence of wind in the center of large cities, its concentration increases tenfold. Regular daily changes in the carbon dioxide content in the surface layers, associated with the rhythm of plant photosynthesis, and seasonal, due to changes in the intensity of respiration of living organisms, mainly the microscopic population of soils. Increased air saturation with carbon dioxide occurs in zones of volcanic activity, near thermal springs and other underground outlets of this gas.

Low air density determines its low lifting force and insignificant bearing capacity.

The inhabitants of the air must have their own support system that supports the body: plants - a variety of mechanical tissues, animals - a solid or, much less often, a hydrostatic skeleton.

Wind

storms

Pressure

The low density of air causes a relatively low pressure on land. Normally, it is equal to 760 mm Hg, Art. As altitude increases, pressure decreases. At an altitude of 5800 m, it is only half normal. Low pressure may limit the distribution of species in the mountains. For most vertebrates, the upper limit of life is about 6000 m. A decrease in pressure entails a decrease in oxygen supply and dehydration of animals due to an increase in respiratory rate.

Approximately the same are the limits of advancement to the mountains of higher plants. Somewhat more hardy are arthropods (springtails, mites, spiders) that can be found on glaciers above the vegetation boundary.

In general, all terrestrial organisms are much more stenobatic than aquatic ones.

Ground-Air Habitat

In the course of evolution, this environment was mastered later than the water. Environmental factors in the terrestrial-air environment differ from other habitats in high light intensity, significant fluctuations in air temperature and humidity, the correlation of all factors with geographical location, the change of seasons of the year and time of day.

The environment is gaseous, therefore it is characterized by low humidity, density and pressure, high oxygen content.

Characterization of abiotic environmental factors of light, temperature, humidity - see the previous lecture.

Gas composition of the atmosphere is also an important climatic factor. Approximately 3-3.5 billion years ago, the atmosphere contained nitrogen, ammonia, hydrogen, methane and water vapor, and there was no free oxygen in it. The composition of the atmosphere was largely determined by volcanic gases.

At present, the atmosphere consists mainly of nitrogen, oxygen, and relatively smaller amounts of argon and carbon dioxide.

All other gases present in the atmosphere are contained only in trace amounts. Of particular importance for the biota is the relative content of oxygen and carbon dioxide.

Only in places, under specific conditions, is a temporary deficit created, for example, in accumulations of decaying plant residues, stocks of grain, flour, etc.

The content of carbon dioxide can vary in certain areas of the surface layer of air in a fairly significant range. For example, in the absence of wind in the center of large cities, its concentration increases tenfold. Regular daily changes in the carbon dioxide content in the surface layers, associated with the rhythm of plant photosynthesis, and seasonal, due to changes in the intensity of respiration of living organisms, mainly the microscopic population of soils.

Increased air saturation with carbon dioxide occurs in zones of volcanic activity, near thermal springs and other underground outlets of this gas. The low content of carbon dioxide inhibits the process of photosynthesis.

Under indoor conditions, the rate of photosynthesis can be increased by increasing the concentration of carbon dioxide; this is used in the practice of greenhouse and greenhouse farming.

Air nitrogen for most inhabitants of the terrestrial environment is an inert gas, but a number of microorganisms (nodule bacteria, Azotobacter, clostridia, blue-green algae, etc.) have the ability to bind it and involve it in the biological cycle.

Local impurities entering the air can also significantly affect living organisms.

This is especially true for toxic gaseous substances - methane, sulfur oxide (IV), carbon monoxide (II), nitrogen oxide (IV), hydrogen sulfide, chlorine compounds, as well as particles of dust, soot, etc., polluting the air in industrial areas. The main modern source of chemical and physical pollution of the atmosphere is anthropogenic: the work of various industrial enterprises and transport, soil erosion, etc.

n. Sulfur oxide (SO2), for example, is toxic to plants even at concentrations from one fifty-thousandth to one millionth of the volume of air .. Some plant species are especially sensitive to SO2 and serve as a sensitive indicator of its accumulation in the air (for example , lichens.

Low air density determines its low lifting force and insignificant bearing capacity. The inhabitants of the air must have their own support system that supports the body: plants - a variety of mechanical tissues, animals - a solid or, much less often, a hydrostatic skeleton.

In addition, all the inhabitants of the air environment are closely connected with the surface of the earth, which serves them for attachment and support. Life in a suspended state in the air is impossible. True, many microorganisms and animals, spores, seeds and pollen of plants are regularly present in the air and are carried by air currents (anemochory), many animals are capable of active flight, but in all these species the main function of their life cycle is reproduction. - carried out on the surface of the earth.

For most of them, being in the air is associated only with resettlement or the search for prey.

Wind It has a limiting effect on the activity and even distribution of organisms. Wind can even change the appearance of plants, especially in habitats such as alpine zones where other factors are limiting. In open mountain habitats, wind limits plant growth, causing plants to bend to the windward side.

In addition, wind increases evapotranspiration in low humidity conditions. Of great importance are storms, although their action is purely local. Hurricanes, as well as ordinary winds, are capable of transporting animals and plants over long distances and thereby changing the composition of communities.

Pressure, apparently, is not a limiting factor of direct action, but it is directly related to weather and climate, which have a direct limiting effect.

The low density of air causes a relatively low pressure on land. Normally, it is equal to 760 mm Hg, Art. As altitude increases, pressure decreases. At an altitude of 5800 m, it is only half normal.

Low pressure may limit the distribution of species in the mountains.

For most vertebrates, the upper limit of life is about 6000 m. A decrease in pressure entails a decrease in oxygen supply and dehydration of animals due to an increase in respiratory rate. Approximately the same are the limits of advancement to the mountains of higher plants. Somewhat more hardy are arthropods (springtails, mites, spiders) that can be found on glaciers above the vegetation boundary.

A distinctive feature of the ground-air environment is the presence of air (a mixture of various gases) in it.

Air has a low density, so it cannot act as a support for organisms (with the exception of flying ones). It is the low density of air that determines its insignificant resistance when organisms move along the soil surface. At the same time, it makes it difficult to move them in the vertical direction. The low air density also determines the low pressure on land (760 mm Hg = 1 atm). Air, smaller than water, blocks the penetration of sunlight. It has a higher transparency than water.

The gas composition of the air is constant (you know about this from the geography course). Oxygen and carbon dioxide, as a rule, are not limiting factors. Water vapor and various pollutants are present as impurities in the air.

Over the past century, as a result of human activities in the atmosphere, the content of various pollutants has sharply increased. Among them, the most dangerous are: nitrogen and sulfur oxides, ammonia, formaldehyde, heavy metals, hydrocarbons, etc. Living organisms are practically not adapted to them. For this reason, air pollution is a serious global environmental problem. Its solution requires the implementation of environmental measures at the level of all states of the Earth.

Air masses move in horizontal and vertical directions. This leads to the emergence of such an environmental factor as wind. Wind can cause shifting of sands in deserts (sandstorms). It is able to blow out soil particles on any terrain, reducing land fertility (wind erosion). Wind has a mechanical effect on plants. It is capable of causing windblows (reversing of trees with roots), windbreaks (fractures of tree trunks), deformation of the tree crown. The movement of air masses significantly affects the distribution of precipitation and the temperature regime in the ground-air environment.

Water regime of the ground-air environment

From the course of geography, you know that the ground-air environment can be both extremely saturated with moisture (tropics) and very poor in it (deserts). Precipitation is unevenly distributed both seasonally and geographically. Humidity in the environment fluctuates over a wide range. It is the main limiting factor for living organisms.

Temperature regime of the ground-air environment

The temperature in the ground-air environment has a daily and seasonal periodicity. Organisms have adapted to it since the emergence of life on land. Therefore, temperature is less likely than humidity to act as a limiting factor.

Adaptations of plants and animals to life in the ground-air environment

With the release of plants on land, they developed tissues. You studied the structure of plant tissues in the 7th grade biology course. Due to the fact that air cannot serve as a reliable support, mechanical tissues (wood and bast fibers) arose in plants. A wide range of changes in climatic factors caused the formation of dense integumentary tissues - periderm, crust. Due to the mobility of air (wind), plants have developed adaptations for pollination, the spread of spores, fruits and seeds.

The life of animals in suspension in the air is impossible due to its low density. Many of the species (insects, birds) have adapted to active flight and can stay in the air for a long time. But their reproduction occurs on the surface of the soil.

The movement of air masses in horizontal and vertical directions is used by some small organisms for passive settlement. In this way, protists, spiders, and insects settle. The low air density caused the improvement in animals in the process of evolution of the external (arthropods) and internal (vertebral) skeletons. For the same reason, there is a limitation of the maximum mass and size of the body of terrestrial animals. The largest land animal, the elephant (weight up to 5 tons), is much smaller than the sea giant, the blue whale (up to 150 tons). Thanks to the appearance of different types of limbs, mammals were able to populate areas of land with a variety of relief patterns.

General characteristics of the soil as a living environment

Soil is the top layer of the earth's crust that is fertile. It was formed as a result of the interaction of climatic and biological factors with the underlying rock (sand, clay, etc.). The soil is in contact with the air and acts as a support for terrestrial organisms. It is also a source of mineral nutrition for plants. At the same time, soil is a living environment for many types of organisms. The soil is characterized by the following properties: density, humidity, temperature, aeration (air supply), environmental reaction (pH), salinity.

Soil density increases with depth. Humidity, temperature and soil aeration are closely interconnected and interdependent. Temperature fluctuations in the soil are smoothed compared to the surface air and are no longer traced at a depth of 1-1.5 m. Well-moistened soils warm up slowly and cool down slowly. An increase in soil moisture and temperature worsens its aeration, and vice versa. The hydrothermal regime of the soil and its aeration depend on the structure of the soil. Clay soils are more water-retaining than sandy soils. But they are less aerated and warm up worse. According to the reaction of the environment, soils are divided into three types: acidic (pH< 7,0), нейтральные (рН ≈ 7,0) и щелочные (рН > 7,0).

Adaptations of plants and animals to life in the soil

The soil in the life of plants performs the functions of fixing, water supply, and a source of mineral nutrition. The concentration of nutrients in the soil has led to the development of root systems and conductive tissues in plants.

Animals living in the soil have a number of adaptations. They are characterized by different ways of moving in the soil. It can be digging moves and holes, like a bear and a mole. Earthworms can push apart soil particles and make passages. Insect larvae are able to crawl among soil particles. In this regard, in the process of evolution, appropriate adaptations have been developed. Digging organisms developed digging limbs. Annelids have a hydrostatic skeleton, while insects and centipedes have claws.

Soil animals have a short compact body with non-wetting covers (mammals) or covered with mucus. Life in the soil as a habitat has led to atrophy or underdevelopment of the organs of vision. The mole has tiny, underdeveloped eyes often hidden under a fold of skin. To facilitate movement in narrow soil passages, mole wool acquired the ability to fit in two directions.

In the ground-air environment, organisms are surrounded by air. It has low humidity, density and pressure, high transparency and oxygen content. Humidity is the main limiting factor. The soil as a living environment is characterized by high density, a certain hydrothermal regime, and aeration. Plants and animals have developed a variety of adaptations to life in the ground-air and soil environments.

Ground-Air Habitat

BASIC LIFE ENVIRONMENTS

WATER ENVIRONMENT

The aquatic environment of life (hydrosphere) occupies 71% of the area of the globe. More than 98% of water is concentrated in the seas and oceans, 1.24% - ice of the polar regions, 0.45% - fresh water of rivers, lakes, swamps.

There are two ecological regions in the oceans:

water column - pelagial, and bottom - benthal.

Approximately 150,000 species of animals live in the aquatic environment, or about 7% of their total number, and 10,000 species of plants - 8%. There are the following ecological groups of hydrobionts. Pelagial - inhabited by organisms subdivided into nekton and plankton.

Nekton (nektos - floating) - this is a collection of pelagic actively moving animals that do not have a direct connection with the bottom. They are mainly large animals that can travel long distances and strong water currents. They are characterized by a streamlined body shape and well-developed organs of movement (fish, squid, pinnipeds, whales). In fresh waters, nekton, in addition to fish, includes amphibians and actively moving insects.

Plankton (wandering, soaring) - this is a collection of pelagic organisms that do not have the ability for fast active movement. They are divided into phyto- and zooplankton (small crustaceans, protozoa - foraminifera, radiolarians; jellyfish, pteropods). Phytoplankton are diatoms and green algae.

Neuston- a set of organisms that inhabit the surface film of water at the border with the air. These are larvae of desyatipods, barnacles, copepods, gastropods and bivalves, echinoderms, and fish. Passing through the larval stage, they leave the surface layer, which served them as a refuge, move to live on the bottom or pelagial.

Playston - this is a collection of organisms, part of the body of which is above the surface of the water, and the other in the water - duckweed, siphonophores.

Benthos (depth) - a group of organisms that live at the bottom of water bodies. It is subdivided into phytobenthos and zoobenthos. Phytobenthos - algae - diatoms, green, brown, red and bacteria; flowering plants near the coasts - zostera, ruppia. Zoobenthos - foraminifera, sponges, coelenterates, worms, mollusks, fish.

In the life of aquatic organisms, the vertical movement of water, density, temperature, light, salt, gas (oxygen and carbon dioxide content) regimes, and the concentration of hydrogen ions (pH) play an important role.

Temperature regime: It differs in water, firstly, by a smaller influx of heat, and secondly, by greater stability than on land. Part of the thermal energy entering the water surface is reflected, part is spent on evaporation. The evaporation of water from the surface of water bodies, which consumes about 2263.8 J/g, prevents overheating of the lower layers, and the formation of ice, which releases the heat of fusion (333.48 J/g), slows down their cooling. The change in temperature in flowing waters follows its changes in the surrounding air, differing in a smaller amplitude.

In lakes and ponds of temperate latitudes, the thermal regime is determined by a well-known physical phenomenon - water has a maximum density at 4 ° C. The water in them is clearly divided into three layers:

1. epilimnion- the upper layer whose temperature experiences sharp seasonal fluctuations;

2. metalimnion- transitional, temperature jump layer, there is a sharp temperature drop;

3. hypolimnion- a deep-sea layer, reaching the very bottom, where the temperature varies slightly throughout the year.

In summer, the warmest layers of water are located at the surface, and the coldest - at the bottom. This type of layered temperature distribution in a reservoir is called direct stratification. In winter, as the temperature drops, reverse stratification: the surface layer has a temperature close to 0 C, at the bottom the temperature is about 4 C, which corresponds to its maximum density. Thus, the temperature rises with depth. This phenomenon is called temperature dichotomy, observed in most lakes of the temperate zone in summer and winter. As a result of the temperature dichotomy, the vertical circulation is disturbed - a period of temporary stagnation sets in - stagnation.

In spring, surface water, due to heating to 4C, becomes denser and sinks deeper, and warmer water rises in its place from the depth. As a result of such vertical circulation, homothermy occurs in the reservoir, i.e. for some time the temperature of the entire water mass is equalized. With a further increase in temperature, the upper layers become less dense and no longer fall down - summer stagnation. In autumn, the surface layer cools, becomes denser and sinks deeper, displacing warmer water to the surface. This happens before the onset of autumn homothermy. When surface waters are cooled below 4C, they become less dense and again remain on the surface. As a result, water circulation stops and winter stagnation sets in.

Water has a significant density(800 times) superior to air) and viscosity. AT On average, in the water column, for every 10 m of depth, the pressure increases by 1 atm. These features affect plants in that they develop very little or no mechanical tissue at all, so their stems are very elastic and easily bent. Most aquatic plants are inherent in buoyancy and the ability to be suspended in the water column; in many aquatic animals, the integument is lubricated with mucus, which reduces friction during movement, and the body takes on a streamlined shape. Many inhabitants are relatively stenobatny and confined to certain depths.

Transparency and light mode. This especially affects the distribution of plants: in muddy water bodies, they live only in the surface layer. The light regime is also determined by the regular decrease in light with depth due to the fact that water absorbs sunlight. At the same time, rays with different wavelengths are absorbed differently: reds are the fastest, while blue-greens penetrate to considerable depths. The color of the environment at the same time changes, gradually moving from greenish to green, blue, blue, blue-violet, replaced by constant darkness. Accordingly, with depth, green algae are replaced by brown and red ones, the pigments of which are adapted to capture sunlight with different wavelengths. The color of animals also naturally changes with depth. The surface layers of the water are inhabited by brightly and diversely colored animals, while the deep-sea species are devoid of pigments. The twilight is inhabited by animals painted in colors with a reddish tint, which helps them hide from enemies, since red in blue-violet rays is perceived as black.

The absorption of light in water is the stronger, the lower its transparency. Transparency is characterized by extreme depth, where a specially lowered Secchi disk (a white disk with a diameter of 20 cm) is still visible. Hence, the boundaries of photosynthesis zones vary greatly in different water bodies. In the purest waters, the photosynthesis zone reaches a depth of 200 m.

Salinity of water. Water is an excellent solvent for many mineral compounds. As a result, natural water bodies have a certain chemical composition. The most important are sulfates, carbonates, chlorides. The amount of dissolved salts per 1 liter of water in fresh water does not exceed 0.5 g, in the seas and oceans - 35 g. Freshwater plants and animals live in a hypotonic environment, i.e. an environment in which the concentration of solutes is lower than in body fluids and tissues. Due to the difference in osmotic pressure outside and inside the body, water constantly penetrates into the body, and fresh water hydrobionts are forced to intensively remove it. In this regard, they have well-defined processes of osmoregulation. In protozoa, this is achieved by the work of excretory vacuoles, in multicellular organisms, by the removal of water through the excretory system. Typically marine and typically freshwater species do not tolerate significant changes in water salinity - stenohaline organisms. Eurygalline - freshwater pike perch, bream, pike, from the sea - the mullet family.

Gas mode The main gases in the aquatic environment are oxygen and carbon dioxide.

Oxygen is the most important environmental factor. It enters the water from the air and is released by plants during photosynthesis. Its content in water is inversely proportional to temperature; with decreasing temperature, the solubility of oxygen in water (as well as other gases) increases. In layers heavily populated by animals and bacteria, oxygen deficiency can be created due to its increased consumption. Thus, in the world's oceans, depths rich in life from 50 to 1000 m are characterized by a sharp deterioration in aeration. It is 7-10 times lower than in surface waters inhabited by phytoplankton. Near the bottom of water bodies, conditions can be close to anaerobic.

Carbon dioxide - dissolves in water about 35 times better than oxygen and its concentration in water is 700 times greater than in the atmosphere. Provides photosynthesis of aquatic plants and participates in the formation of calcareous skeletal formations of invertebrates.

Hydrogen ion concentration (pH)- freshwater pools with pH = 3.7-4.7 are considered acidic, 6.95-7.3 - neutral, with pH 7.8 - alkaline. In fresh water bodies, pH even experiences daily fluctuations. Sea water is more alkaline and its pH changes much less than in fresh water. pH decreases with depth. The concentration of hydrogen ions plays an important role in the distribution of hydrobionts.

Ground-Air Habitat

A feature of the land-air environment of life is that the organisms living here are surrounded by a gaseous environment characterized by low humidity, density and pressure, high oxygen content. As a rule, animals in this environment move along the soil (solid substrate), and plants take root in it.

In the ground-air environment, the operating environmental factors have a number of characteristic features: higher light intensity in comparison with other environments, significant temperature fluctuations, changes in humidity depending on the geographical location, season and time of day. The impact of the factors listed above is inextricably linked with the movement of air masses - the wind.

In the process of evolution, living organisms of the ground-air environment have developed characteristic anatomical, morphological, and physiological adaptations.

Let us consider the features of the impact of the main environmental factors on plants and animals in the ground-air environment.

Air. Air as an environmental factor is characterized by a constant composition - oxygen in it is usually about 21%, carbon dioxide 0.03%.

Low air density determines its low lifting force and insignificant bearing capacity. All inhabitants of the air environment are closely connected with the surface of the earth, which serves them for attachment and support. The density of the air medium does not provide high resistance to organisms when they move along the surface of the earth, however, it makes it difficult to move vertically. For most organisms, staying in the air is associated only with dispersal or the search for prey.

The small lifting force of air determines the limiting mass and size of terrestrial organisms. The largest animals living on the surface of the earth are smaller than the giants of the aquatic environment. Large mammals (the size and weight of a modern whale) could not live on land, as they would be crushed by their own weight.

Low air density creates a slight resistance to movement. The ecological benefits of this property of the air environment were used by many terrestrial animals in the course of evolution, acquiring the ability to fly. 75% of the species of all terrestrial animals are capable of active flight, mainly insects and birds, but flyers are also found among mammals and reptiles.

Due to the mobility of air, the vertical and horizontal movements of air masses existing in the lower layers of the atmosphere, passive flight of a number of organisms is possible. Many species have developed anemochory - resettlement with the help of air currents. Anemochory is characteristic of spores, seeds and fruits of plants, protozoan cysts, small insects, spiders, etc. Organisms passively transported by air currents were collectively called aeroplankton by analogy with planktonic inhabitants of the aquatic environment.

The main ecological role of horizontal air movements (winds) is indirect in strengthening and weakening the impact on terrestrial organisms of such important environmental factors as temperature and humidity. Winds increase the return of moisture and heat to animals and plants.

Gas composition of air in the surface layer, the air is quite homogeneous (oxygen - 20.9%, nitrogen - 78.1%, inert gases - 1%, carbon dioxide - 0.03% by volume) due to its high diffusion capacity and constant mixing by convection and wind flows. However, various admixtures of gaseous, droplet-liquid and solid (dust) particles entering the atmosphere from local sources can be of significant ecological importance.

The high oxygen content contributed to an increase in the metabolism of terrestrial organisms, and on the basis of the high efficiency of oxidative processes, homoiothermia of animals arose. Oxygen, due to its constantly high content in the air, is not a factor limiting life in the terrestrial environment. Only in places, under specific conditions, is a temporary deficit created, for example, in accumulations of decaying plant residues, stocks of grain, flour, etc.

edaphic factors. Soil properties and terrain also affect the living conditions of terrestrial organisms, primarily plants. The properties of the earth's surface that have an ecological impact on its inhabitants are called edaphic environmental factors.

The nature of the root system of plants depends on the hydrothermal regime, aeration, composition, composition and structure of the soil. For example, the root systems of tree species (birch, larch) in areas with permafrost are located at a shallow depth and spread out in breadth. Where there is no permafrost, the root systems of these same plants are less spread out and penetrate deeper. In many steppe plants, the roots can get water from a great depth, at the same time they have many surface roots in the humus soil horizon, from where the plants absorb mineral nutrients.

The terrain and the nature of the soil affect the specifics of the movement of animals. For example, ungulates, ostriches, bustards living in open spaces need solid ground to enhance repulsion when running fast. In lizards living on loose sands, the fingers are bordered with a fringe of horn scales, which increases the surface of the support. For terrestrial inhabitants digging holes, dense soils are unfavorable. The nature of the soil in some cases affects the distribution of terrestrial animals that dig holes, burrow into the ground to escape heat or predators, or lay eggs in the soil, etc.

Weather and climatic features. Living conditions in the ground-air environment are complicated, in addition, by weather changes. Weather is the continuously changing state of the atmosphere near the earth's surface, up to a height of about 20 km (the boundary of the troposphere). Weather variability is manifested in the constant variation in the combination of such environmental factors as air temperature and humidity, cloudiness, precipitation, wind strength and direction, etc. Along with their regular alternation in the annual cycle, weather changes are characterized by non-periodic fluctuations, which significantly complicates the conditions for the existence of terrestrial organisms. The weather affects the life of aquatic inhabitants to a much lesser extent and only on the population of the surface layers.

The climate of the area. The long-term weather regime characterizes the climate of the area. The concept of climate includes not only the average values of meteorological phenomena, but also their annual and daily course, deviations from it and their frequency. The climate is determined by the geographical conditions of the area.

The zonal diversity of climates is complicated by the action of monsoon winds, the distribution of cyclones and anticyclones, the influence of mountain ranges on the movement of air masses, the degree of distance from the ocean, and many other local factors.

For most terrestrial organisms, especially small ones, it is not so much the climate of the area that is important, but the conditions of their immediate habitat. Very often, local elements of the environment (relief, vegetation, etc.) change the regime of temperature, humidity, light, air movement in a particular area in such a way that it differs significantly from the climatic conditions of the area. Such local climate modifications that take shape in the surface layer of air are called microclimates. In each zone, the microclimates are very diverse. It is possible to single out microclimates of arbitrarily small areas. For example, a special mode is created in the corollas of flowers, which is used by the inhabitants living there. A special stable microclimate occurs in burrows, nests, hollows, caves, and other closed places.

Precipitation. In addition to providing water and creating moisture reserves, they can play another ecological role. Thus, heavy rain showers or hail sometimes have a mechanical effect on plants or animals.

The ecological role of snow cover is especially diverse. Daily temperature fluctuations penetrate into the snow thickness only up to 25 cm; deeper, the temperature almost does not change. With frosts of -20-30 C under a layer of snow of 30-40 cm, the temperature is only slightly below zero. Deep snow cover protects the buds of renewal, protects the green parts of plants from freezing; many species go under the snow without shedding foliage, for example, hairy sorrel, Veronica officinalis, etc.

Small terrestrial animals also lead an active lifestyle in winter, laying entire galleries of passages under the snow and in its thickness. For a number of species that feed on snowy vegetation, even winter reproduction is characteristic, which is noted, for example, in lemmings, wood and yellow-throated mice, a number of voles, water rats, etc. Grouse birds - hazel grouse, black grouse, tundra partridges - burrow into the snow for the night.

Winter snow cover prevents large animals from foraging. Many ungulates (reindeer, wild boars, musk oxen) feed exclusively on snowy vegetation in winter, and deep snow cover, and especially a hard crust on its surface that occurs in ice, doom them to starvation. The depth of snow cover can limit the geographic distribution of species. For example, real deer do not penetrate north into those areas where the snow thickness in winter is more than 40-50 cm.

Light mode. The amount of radiation reaching the Earth's surface is determined by the geographic latitude of the area, the length of the day, the transparency of the atmosphere and the angle of incidence of the sun's rays. Under different weather conditions, 42-70% of the solar constant reaches the Earth's surface. Illumination on the Earth's surface varies widely. It all depends on the height of the Sun above the horizon or the angle of incidence of the sun's rays, the length of the day and weather conditions, and the transparency of the atmosphere. The intensity of the light also fluctuates depending on the time of year and the time of day. In some areas of the Earth, the quality of light is also unequal, for example, the ratio of long-wave (red) and short-wave (blue and ultraviolet) rays. Shortwave rays, as is known, are more absorbed and scattered by the atmosphere than longwave ones.

Animals are settled almost on the entire surface of the Earth. Due to their mobility, the ability to adapt evolutionarily to colder conditions of existence, due to their lack of direct dependence on sunlight, animals have occupied more habitats than plants. However, it should be remembered that animals depend on plants, as plants serve as a source of food for them (for herbivores, and predators eat herbivores).

Here, in the context of animal habitats, we will understand animal habitats.

In total, there are four habitats for animals. These are 1) ground-air, 2) water, 3) soil and 4) other living organisms. Speaking about the ground-air environment of life, sometimes it is divided into ground and, separately, air. However, even flying animals land on the ground sooner or later. In addition, moving on the ground, the animal is also in the air. Therefore, the ground and air environments are combined into one ground-air environment.

There are animals that live in two environments at once. For example, many amphibians (frogs) live both in water and on land, a number of rodents live in soil and on the surface of the earth.

Ground-Air Habitat

In the ground-air environment, most species of animals. The land turned out to be, in a sense, the most convenient environment for their life. Although in evolution animals (and plants) arose in water and only later came to the surface.

Most worms, insects, amphibians, reptiles, birds and mammals live on land. Many species of animals are capable of flight, so they spend part of their lives exclusively in the air.

Animals of the ground-air environment are usually characterized by high mobility, good vision.

The land-air environment is characterized by a wide variety of habitat conditions (tropical forests and temperate forests, meadows and steppes, deserts, tundras, and much more). Therefore, the animals of this environment of life are characterized by great diversity, they can differ greatly from each other.

aquatic habitat

The aquatic habitat differs from the air in greater density. Here animals can afford to have very massive bodies (whales, sharks) as the water supports them and makes their bodies lighter. However, moving in a dense environment is more difficult, so aquatic animals most often have a streamlined body shape.

Almost no sunlight penetrates into the depths of the sea, so the organs of vision may be poorly developed in deep-sea animals.

Aquatic animals are divided into plankton, nekton and benthos. Plankton passively swims in the water column (for example, unicellular), nekton- these are actively swimming animals (fish, whales, etc.), benthos lives on the bottom (corals, sponges, etc.).

soil habitat

The soil as a habitat is characterized by a very high density and lack of sunlight. Here the animals do not need the organs of sight. Therefore, they are either not developed (worms) or reduced (moles). On the other hand, in the soil there are not such significant temperature drops as on the surface. Many worms, insect larvae, ants live in the soil. There are also soil inhabitants among mammals: moles, mole rats, burrowing animals.

LECTURE 4

ENVIRONMENTS OF LIFE AND ADAPTATION OF ORGANISMS TO THEM.

Water environment.

This is the most ancient environment in which life arose and evolved for a long time even before the moment when the first organisms appeared on land. According to the composition of the aquatic environment of life, two of its main variants are distinguished: freshwater and marine environments.

More than 70% of the planet's surface is covered with water. However, due to the comparative evenness of the conditions of this environment (“water is always wet”), the diversity of organisms in the aquatic environment is much less than on land. Only every tenth species of the plant kingdom is associated with the aquatic environment, the diversity of aquatic animals is somewhat higher. The general ratio of the number of land/water species is about 1:5.

The density of water is 800 times higher than the density of air. And the pressure on the organisms inhabiting it is also much higher than in terrestrial conditions: for every 10 m of depth, it increases by 1 atm. One of the main directions of adaptation of organisms to life in the aquatic environment is to increase buoyancy by increasing the surface of the body and the formation of tissues and organs containing air. Organisms can float in the water (like representatives of plankton - algae, protozoa, bacteria) or actively move, like fish that form nekton. A significant part of the organisms is attached to the bottom surface or moves along it. As already noted, an important factor in the aquatic environment is the current.

Table 1 - Comparative characteristics of habitats and adaptation of living organisms to them

The basis of the production of most aquatic ecosystems are autotrophs, using sunlight that breaks through the water column. The possibility of "piercing" this thickness is determined by the transparency of the water. In the clear water of the ocean, depending on the angle of incidence of sunlight, autotrophic life is possible up to a depth of 200 m in the tropics and 50 m in high latitudes (for example, in the seas of the Arctic Ocean). In strongly disturbed freshwater reservoirs, a layer inhabited by autotrophs (it is called photic), may be only a few tens of centimeters.

The red part of the light spectrum is most actively absorbed by water, therefore, as noted, the deep waters of the seas are inhabited by red algae, which are capable of assimilating green light due to additional pigments. The transparency of water is determined by a simple device - the Secchi disk, which is a white-colored circle with a diameter of 20 cm. The degree of water transparency is judged by the depth at which the disk becomes indistinguishable.

The most important characteristic of water is its chemical composition - the content of salts (including nutrients), gases, hydrogen ions (pH). According to the concentration of nutrients, especially phosphorus and nitrogen, water bodies are divided into oligotrophic, mesotrophic and eutrophic. With an increase in the content of nutrients, for example, when a reservoir is polluted with wastewater, the process of eutrophication of aquatic ecosystems occurs.

The oxygen content in water is about 20 times lower than in the atmosphere, and is 6-8 ml/l. It decreases with increasing temperature, as well as in stagnant water bodies in winter, when the water is isolated from the atmosphere by a layer of ice. A decrease in oxygen concentration can cause the death of many inhabitants of aquatic ecosystems, excluding species that are especially resistant to oxygen deficiency, such as crucian carp or tench, which can live even when the oxygen content drops to 0.5 ml/l. The content of carbon dioxide in water, on the contrary, is higher than in the atmosphere. In sea water, it can contain up to 40-50 ml / l, which is about 150 times higher than in the atmosphere. Consumption of carbon dioxide by phytoplankton during intensive photosynthesis does not exceed 0.5 ml/l per day.

The concentration of hydrogen ions in water (pH) can vary within 3.7-7.8. Waters with a pH of 6.45 to 7.3 are considered neutral. As already noted, with a decrease in pH, the biodiversity of organisms inhabiting the aquatic environment rapidly decreases. Crayfish, many types of mollusks die at pH below 6, perch and pike can withstand pH up to 5, eel and char survive when the pH drops to 5-4.4. In more acidic waters, only some species of zooplankton and phytoplankton survive. Acid rains associated with the release of large amounts of sulfur and nitrogen oxides into the atmosphere by industrial enterprises have become the cause of acidification of the waters of lakes in Europe and the United States and a sharp depletion of their biological diversity. Oxygen is often the limiting factor. Its content usually does not exceed 1% by volume. With an increase in temperature, enrichment with organic matter and weak mixing, the oxygen content in water decreases. The low availability of oxygen for organisms is also associated with its weak diffusion (it is thousands of times less in water than in air). The second limiting factor is light. Illumination decreases rapidly with depth. In perfectly clean waters, light can penetrate to a depth of 50-60 m, in heavily polluted waters - only a few centimeters.

This environment is the most homogeneous among others. It varies little in space, there are no clear boundaries between individual ecosystems. The amplitudes of the factor values are also small. The difference between the maximum and minimum temperatures here usually does not exceed 50°C (while in the ground-air environment it is up to 100°C). The medium has a high density. For oceanic waters it is equal to 1.3 g/cm 3 , for fresh waters it is close to unity. The pressure only changes with depth: each 10-meter layer of water increases the pressure by 1 atmosphere.

There are few warm-blooded animals in the water, or homoiothermic(Greek homa - the same, thermo - heat), organisms. This is the result of two causes: a small temperature fluctuation and a lack of oxygen. The main adaptive mechanism of homoiothermia is resistance to unfavorable temperatures. In water, such temperatures are unlikely, and in the deep layers the temperature is almost constant (+4°C). Maintaining a constant body temperature is necessarily associated with intensive metabolic processes, which is possible only with a good supply of oxygen. There are no such conditions in water. Warm-blooded animals of the aquatic environment (whales, seals, fur seals, etc.) are former inhabitants of the land. Their existence is impossible without periodic communication with the air environment.

Typical inhabitants of the aquatic environment have a variable body temperature and belong to the group poikiothermal(Greek poikios - varied). To some extent, they compensate for the lack of oxygen by increasing the contact of the respiratory organs with water. Many water dwellers (hydrobionts) consume oxygen through all the integuments of the body. Often, breathing is combined with a filtration type of nutrition, in which a large amount of water is passed through the body. Some organisms during periods of acute lack of oxygen are able to drastically slow down their vital activity, up to the state suspended animation(almost complete cessation of metabolism).

Organisms adapt to high water density mainly in two ways. Some use it as a support and are in a state of free soaring. The density (specific gravity) of such organisms usually differs little from the density of water. This is facilitated by the complete or almost complete absence of the skeleton, the presence of outgrowths, droplets of fat in the body or air cavities. Such organisms are grouped plankton(Greek planktos - wandering). There are plant (phyto-) and animal (zoo-) plankton. The size of planktonic organisms is usually small. But they account for the bulk of aquatic life.

Actively moving organisms (swimmers) adapt to overcome the high density of water. They are characterized by an elongated body shape, well-developed muscles, and the presence of friction-reducing structures (mucus, scales). In general, the high density of water results in a decrease in the proportion of the skeleton in the total body mass of hydrobionts compared to terrestrial organisms. In conditions of lack of light or its absence, organisms use sound for orientation. It spreads much faster in water than in air. To detect various obstacles, reflected sound is used by the type of echolocation. Odor phenomena are also used for orientation (odors are felt much better in water than in air). In the depths of the waters, many organisms have the property of self-luminescence (bioluminescence).

Plants that live in the water column use the most deeply penetrating blue, blue and blue-violet rays in the process of photosynthesis. Accordingly, the color of plants changes with depth from green to brown and red.

The following groups of aquatic organisms are distinguished adequately to adaptive mechanisms: plankton- free floating nekton(Greek nektos - floating) - actively moving, benthos(Greek benthos - depth) - inhabitants of the bottom, pelagos(Greek pelagos - open sea) - inhabitants of the water column, neuston- inhabitants of the upper film of water (part of the body can be in the water, part - in the air).

Human impact on the aquatic environment is manifested in a decrease in transparency, a change in the chemical composition (pollution) and temperature (thermal pollution). The consequence of these and other impacts is oxygen depletion, reduced productivity, changes in species composition, and other deviations from the norm.

Ground-air environment.

Air has a much lower density than water. For this reason, the development of the air environment, which occurred much later than the origin of life and its development in the aquatic environment, was accompanied by an increase in the development of mechanical tissues, which allowed organisms to resist the action of the law of universal gravitation and wind (skeleton in vertebrates, chitinous shells in insects, sclerenchyma in plants). In conditions of only air, not a single organism can live permanently, and therefore even the best “flyers” (birds and insects) must periodically descend to the ground. The movement of organisms through the air is possible due to special devices - wings in birds, insects, some species of mammals and even fish, parachutes and wings in seeds, air sacs in coniferous pollen, etc.

Air is a poor conductor of heat, and therefore it was in the air environment on land that endothermic (warm-blooded) animals arose, which are easier to keep warm than ectothermic inhabitants of the aquatic environment. For warm-blooded aquatic animals, including giant whales, the aquatic environment is secondary; the ancestors of these animals once lived on land.

Life in the air required more complex reproductive mechanisms that would eliminate the risk of germ cells drying out (multicellular antheridia and archegonia, and then ovules and ovaries in plants, internal fertilization in animals, eggs with a dense shell in birds, reptiles, amphibians, etc. ).

In general, there are many more opportunities for the formation of various combinations of factors in the ground-air environment than in water. It is in this environment that differences in the climate of different regions (and at different heights above sea level within the same region) are most clearly manifested. Therefore, the diversity of terrestrial organisms is much higher than that of aquatic ones.

This environment is one of the most complex both in terms of properties and diversity in space. It is characterized by low air density, large temperature fluctuations (annual amplitudes up to 100°C), high atmospheric mobility. Limiting factors are most often a lack or excess of heat and moisture. In some cases, for example, under the canopy of the forest, there is a lack of light.

Large fluctuations in temperature over time and its significant variability in space, as well as a good supply of oxygen, were the motives for the appearance of organisms with a constant body temperature (homeothermic). Homeothermy allowed land dwellers to significantly expand their habitat (species ranges), but this is inevitably associated with increased energy expenditure.

For organisms of the ground-air environment, three mechanisms of adaptation to the temperature factor are typical: physical, chemical, behavioral. Physical controlled by heat transfer. Its factors are skin, body fat, water evaporation (sweating in animals, transpiration in plants). This pathway is characteristic of poikyothermic and homeothermic organisms. Chemical adaptations based on maintaining a certain body temperature. It requires an intense metabolism. Such adaptations are characteristic of homoiothermic and only partially poikyothermic organisms. behavioral path it is carried out by means of the choice of preferred positions by organisms (open to the sun or shaded places, various types of shelter, etc.). It is characteristic of both groups of organisms, but poikyothermic to a greater extent. Plants adapt to the temperature factor mainly through physical mechanisms (covers, water evaporation) and only partially through behavioral ones (rotation of leaf blades relative to the sun's rays, use of the heat of the earth and the warming role of snow cover).

Adaptations to temperature are also carried out through the size and shape of the body of organisms. For heat transfer, large sizes are more advantageous (than the larger the body, the smaller its surface area per unit mass, and hence heat transfer, and vice versa). For this reason, the same species found in colder environments (in the north) tend to be larger than those found in warmer climates. This pattern is called Bergman's rule. Temperature regulation is also carried out through the protruding parts of the body (ears, limbs, olfactory organs). They tend to be smaller in colder regions than in warmer regions. (Allen's rule).

The dependence of heat transfer on body size can be judged by the amount of oxygen consumed during respiration per unit mass by various organisms. It is the larger, the smaller the size of the animals. So, per 1 kg of weight, oxygen consumption (cm 3 / hour) was: horse - 220, rabbit - 480, rat -1800, mouse - 4100.