A habitat is the immediate environment in which a living organism (animal or plant) exists. It can contain both living organisms and inanimate objects and any number of varieties of organisms from several species to several thousand, coexisting in a certain living space. Air-terrestrial habitat includes such areas earth's surface like mountains, savannas, forests, tundra, polar ice and others.

Habitat - planet Earth

Different parts of planet Earth are home to a huge biological diversity of living organisms. There are certain types of animal habitats. Hot, arid areas are often covered by hot deserts. Warm, humid regions contain humid

There are 10 main types of land habitats on Earth. Each of them has many varieties, depending on where in the world it is located. Animals and plants that are typical of a particular habitat adapt to the conditions in which they live.

African savannas

This tropical herbaceous aerial-terrestrial community habitat is found in Africa. It is characterized by long dry periods following wet seasons with heavy rainfall. African savannas are home to a huge number of herbivores, as well as strong predators who feed on them.

Mountains

The tops of high mountain ranges are very cold and few plants grow there. Animals living in these high places are adapted to cope with low temperatures, lack of food and steep, rocky terrain.

Evergreen forests

Coniferous forests are often found in cooler areas of the globe: Canada, Alaska, Scandinavia and regions of Russia. Dominated by evergreen spruce trees, these areas are home to animals such as elk, beaver and wolf.

Deciduous trees

In cold, damp areas, many trees grow quickly in summer time, but lose leaves in winter. The number of wildlife in these areas varies seasonally as many migrate to other areas or hibernate during the winter.

Temperate zone

It is characterized by dry grassy prairies and steppes, grasslands, hot summers and Cold winter. This terrestrial-air habitat is home to gregarious herbivores such as antelope and bison.

Mediterranean zone

The lands around Mediterranean Sea They have a hot climate, but there is more rainfall here than in desert areas. These areas are home to shrubs and plants that can only survive if they have access to water and are often filled with many various types insects

Tundra

An air-terrestrial habitat such as the tundra is covered with ice most of the year. Nature comes to life only in spring and summer. Deer live here and birds nest.

Rainforests

These dense green forests grow close to the equator and are home to the richest biological diversity of living organisms. No other habitat can boast as many inhabitants as the rainforest area.

polar ice

Cold regions near the North and South Poles are covered with ice and snow. Here you can find penguins, seals and polar bears who get their food in the icy waters of the ocean.

Animals of the land-air habitat

Habitats are scattered across a vast area of ​​planet Earth. Each is characterized by a certain biological and flora, whose representatives unevenly populate our planet. In colder parts of the world, such as the polar regions, there are not many species of fauna that inhabit these areas and are specially adapted to living in low temperatures. Some animals are distributed throughout the world depending on the plants they eat, for example, the giant panda inhabits areas where

Air-ground habitat

Every living organism needs a home, shelter or environment that can provide security, ideal temperature, food and reproduction - all the things necessary for survival. One of the important functions of a habitat is to provide the ideal temperature, since extreme changes can destroy an entire ecosystem. An important condition also is the presence of water, air, soil and sunlight.

The temperature on Earth is not the same everywhere; in some parts of the planet (Northern and South pole) the thermometer can drop to - 88°C. In other places, especially in the tropics, it is very warm and even hot (up to +50°C). Temperature plays an important role in adaptation processes ground-air environment habitats, for example, animals adapted to low temperatures cannot survive in warm conditions.

The habitat is natural environment in which the organism lives. Animals demand various quantities space. The habitat can be large and occupy an entire forest or small, like a mink. Some inhabitants have to defend and defend a huge territory, while others need small area spaces where they can coexist relatively peacefully with neighbors living nearby.

All living beings inhabiting our planet live in certain conditions that correspond to the level of development, features of organization and vital activity of organisms. Who populates the land-air environment? Features of the environment, which is the most populated, and much more will be discussed in our article.

What is habitat

The habitat of organisms is everything that surrounds them. And these are not only natural objects, but also what is created by man.

The totality of all habitats constitutes the biosphere. This is where life is possible. But man, through his activities, has transformed it so much that scientists identify another formation. It is called the noosphere. This is the shell of the planet created by human activity.

Main groups of environmental factors

All environmental conditions that affect organisms to one degree or another are called environmental factors. They are quite diverse. But according to the nature of their impact, they are divided into several groups.

• The first unites all of them. They are called abiotic. These are the amount of sunlight, air temperature, humidity and radiation levels, wind direction and the nature of the relief. For residents aquatic environment these are the salinity and the type of currents.
• Biotic factors combine all types of influence of living organisms and their relationships with each other. They can be mutually beneficial, neutral predatory, etc.
• Human activities that change the environment are a group of anthropogenic factors.

Habitats of living organisms

The peculiarities of the ground-air habitat are that it is the most diverse and complex. There is a natural explanation for this fact.

Features of the ground-air environment of life

The complexity of the structure and conditions of this environment is explained by the fact that it is located at the junction of several geographical shells - hydro-, litho- and atmosphere. Therefore, the organisms living in it are influenced by the factors of each of them. Their structural features allow them to withstand sudden changes in temperature, chemical and humidity changes.

Abiotic factors of the ground-air environment

Features of the ground-air habitat include several factors. Firstly, this is a low air density. The low density of air masses allows its inhabitants to easily move on the ground or fly.

The next feature is that the air is in constant motion. This “flow” ensures the automatic movement of many inhabitants and their waste products. These are plant seeds, fungal and bacterial spores, small insects and arachnids. At the same time, the atmospheric pressure in this environment is characterized by a low indicator, which is normally 760 mmHg. A change in this value leads to disruption of the physiological processes of local inhabitants. Thus, when pressure drops with altitude, the ability of oxygen to dissolve in the blood plasma decreases. As a result, it becomes smaller, breathing becomes more frequent, which leads to excessive loss of moisture.

Organisms of the ground-air environment

One of the hallmarks of all living things is the ability to adapt. The peculiarities of animals of the land-air environment, as well as other organisms, are that all of them, in the process of evolution, acquired adaptations to sharp changes in temperature, climate and changing seasons.

For example, many plants have modifications to their roots and shoots to survive drought and cold weather. Leek and tulip bulbs, carrot and beet roots, and aloe leaves store water and necessary substances. Spores of bacteria and plants, cells of microscopic animals endure difficult conditions in the state of cysts. At the same time, they are covered with a dense shell, and all metabolic processes are kept to a minimum. When the unfavorable period ends, the cells divide and move on to active existence.

Many animals of the land-air environment have formed a complex system of thermoregulation and heat exchange with the environment, thanks to which their body temperature remains constant regardless of the time of year.

Action of the anthropogenic factor

It is the ground-air environment that is most changed by human activity. Features of the environment, which were initially natural, remained so, perhaps, only in the Arctic deserts. Low temperatures making this natural area uninhabitable. Therefore, the characteristics of organisms in the ground-air environment also lie in the fact that they experience a greater influence of the anthropogenic factor compared to the inhabitants of other ecological niches.

Man transforms natural landscapes and topography, changes the gas composition of the atmosphere, the chemical basis of soils, and affects the cleanliness of water bodies. Not all living organisms have time to adapt to intensely changing conditions caused by the action of the anthropogenic factor. Unfortunately, Negative influence person on the state of the ground-air environment in this moment prevails over all attempts to preserve life.

Global terrestrial-air habitats

How has the land-air environment suffered at the hands of man? Features of the environment, its main physical indicators in the majority natural areas, suitable for life, changed. This led to the emergence of global environmental problems in the world. The activities of industrial enterprises caused a change in the gas composition of the atmosphere. As a result, a higher concentration of carbon dioxide is created in the air than normal, and sulfur and nitrogen oxides and freons accumulate. The result is global warming, Greenhouse effect, destruction of the earth's ozone layer, smog over large cities.

As a result of irrational environmental management, the total area of ​​forests, which are the “lungs” of our planet, is decreasing, providing all living things with oxygen. Over time, mineral resources are exhausted and soil fertility decreases.

So, the most diverse is the ground-air environment. Features of the environment lie in its location at the junction of several natural geographical shells. Its main characteristics are low density, pressure and mobility of air masses, constancy of the gas composition of the atmosphere, variability of thermal conditions, change climatic conditions and seasons. Of particular importance for normal life in the ground-air environment are indicators of humidity and air temperature.

A NEW LOOK Adaptations of organisms to living in the ground-air environmentLiving organisms in ground-air environment surrounded by air. Air has low density and, as a result, 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 just as quickly. The speed of this process is inverse relationship on the amount of water vapor it contains.

Lungs air masses have greater mobility, both horizontally and vertically. This helps maintain a constant 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 terrestrial habitats, due to the high transparency of the atmosphere, does not act as a limiting factor, unlike the aquatic environment.

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

Moisture on land acts as a limiting factor.

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

Low air resistance contributed to the progressive evolution of locomotion systems of terrestrial animals. Thus, mammals acquired the highest speed of movement on land, and birds mastered the air environment, developing the ability to fly.

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

The adaptations of terrestrial organisms to conserve moisture are also diverse. In insects, the body is reliably protected from drying out by a multilayered chitinized cuticle, the outer layer of which contains fats and wax-like substances. Similar water-saving devices 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 represents complex system consisting of solid particles surrounded by air and water.

Depending on the type - clayey, sandy, clayey-sandy etc. - the soil is more or less permeated with cavities filled with a mixture of gases and aqueous solutions. In the soil, compared to the ground 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 underneath contains washed out from the top layer and transformed substances. The bottom layer is represented maternal breed.

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

In the course of evolution, this environment was developed later than the aquatic one. Its peculiarity is that it is gaseous, therefore it is characterized by low humidity, density and pressure, and 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 on the soil or through the air (birds, insects), and plants take root in the soil. In this regard, animals developed lungs and trachea, and plants developed a stomatal apparatus, i.e.

organs with which the land inhabitants of the planet absorb oxygen directly from the air. Skeletal organs have developed strongly, ensuring autonomy of movement on land and supporting the body with all its organs in conditions of insignificant environmental density, thousands of times less than water.

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

Their effects on organisms are inextricably linked with air movement and position relative to the seas and oceans and are very different from the effects in the aquatic environment (Table

Table 5

Habitat conditions for 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	Almost none	Large (can reach 1000 atmospheres)
Temperature	Significant (varies within very wide limits - from -80 to +1ОО°С and more)	Less than the value for the inhabitants of the air (varies much less, usually from -2 to +40°C)
Oxygen	Non-essential (mostly in excess)	Essential (often in short supply)
Suspended solids	Unimportant; not used for food (mainly minerals)	Important (food source, especially organic matter)
Dissolved substances in environment	To some extent (only relevant in soil solutions)	Important (certain quantities required)

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

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

Many of the adaptations were discussed above as examples in characterizing abiotic environmental factors.

Therefore, there is no point in repeating ourselves now, since we will return to them in practical classes.

Soil as a habitat

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

This shell was formed in historically foreseeable time - it is the same age as land life on the planet. For the first time, M.V. answered the question about the origin of soil. Lomonosov (“On the Layers of the Earth”): “...soil originated from the decay of animal and plant bodies...through 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 total, mutual activity of the climate of a given area, its plant and animal organisms, topography and age of the country..., finally, subsoil, i.e.

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

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

Kaczynski (“Soil, its properties and life”, 1975) gives the following definition of soil: “Soil must be understood as all surface layers of rocks, processed and changed by the joint influence of climate (light, heat, air, water), plant and animal organisms” .

Main structural elements soils are: mineral base, organic matter, air and water.

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

Skeletal particle sizes range from boulders and stones to tiny grains of sand and mud particles. The physicochemical properties of soils are determined mainly by the composition of soil-forming 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 and the size of the fragments.

IN temperate climate ideally, if the soil is formed by equal amounts of clay and sand, i.e. represents loam.

In this case, the soils are not at risk of either waterlogging or drying out. Both are equally destructive for 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.

Simpler elements formed as a result of the decomposition of organic matter are again absorbed 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 filling of pores 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, and the decomposition of organic matter is slow. Gradually accumulating, they form peat. Large reserves of peat are typical for swamps, swampy forests, and tundra communities. Peat accumulation is especially pronounced in the northern regions, where coldness and waterlogging of soils are interdependent and complement each other.

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

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

Easily absorbed by plants.

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

Capillary– held around soil particles by surface tension.

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

Plants easily absorb it.

Vaporous– occupies all water-free pores. It 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 a terrestrial environment, on the basis of the high efficiency of oxidative processes in the body, that animal homeothermy 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 deficiency created, for example in accumulations of decomposing plant residues, reserves of grain, flour, etc.

For example, in the absence of wind in the center of large cities, its concentration increases tens of times. There are regular daily changes in the carbon dioxide content in ground 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 saturation of air 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 support.

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

Wind

storms

Pressure

Low air density causes relatively low pressure on land. Normally it is 760 mmHg. 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 respiration rate.

The limits of advancement of higher plants into the mountains are approximately the same. Somewhat more hardy are arthropods (springtails, mites, spiders), which can be found on glaciers above the vegetation line.

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

Ground-air habitat

In the course of evolution, this environment was developed later than the aquatic one. Ecological factors in the ground-air environment differ from other habitats in the high intensity of light, significant fluctuations in temperature and air humidity, the correlation of all factors with geographic location, changing seasons and time of day.

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

Characteristics of abiotic environmental factors: light, temperature, humidity - see 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.

Currently, 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 quantities. Of particular importance for biota is the relative content of oxygen and carbon dioxide.

It was in a terrestrial environment, on the basis of the high efficiency of oxidative processes in the body, that animal homeothermy 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 deficiency created, for example in accumulations of decomposing plant residues, reserves of grain, flour, etc.

The carbon dioxide content can vary in certain areas of the surface layer of air within quite significant limits. For example, in the absence of wind in the center of large cities, its concentration increases tens of times. There are regular daily changes in the carbon dioxide content in the ground layers, associated with the rhythm of plant photosynthesis, and seasonal changes, caused by changes in the respiration rate of living organisms, mainly the microscopic population of soils.

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

In closed ground conditions, it is possible to increase the rate of photosynthesis by increasing the concentration of carbon dioxide; this is used in the practice of greenhouse and greenhouse farming.

Air nitrogen for most inhabitants terrestrial environment represents 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 pollutants entering the air can also significantly affect living organisms.

This especially applies to 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 in concentrations from one fifty-thousandth to one millionth of the volume of air. Some plant species are especially sensitive to S02 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 support. Inhabitants of the air environment must have their own support system that supports the body: plants - with various mechanical tissues, animals - with a solid or, much less often, hydrostatic skeleton.

In addition, all inhabitants of the air 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, staying in the air is associated only with settling or searching for prey.

Wind has a limiting effect on the activity and even distribution of organisms. The wind can even change appearance plants, especially in those habitats, for example in alpine zones, where other factors have a limiting effect. In open mountain habitats, wind limits plant growth and causes plants to bend on the windward side.

In addition, wind increases evapotranspiration in low humidity conditions. Are of great importance storms, although their effect is purely local. Hurricanes, and even ordinary winds, can transport animals and plants over long distances and thereby change the composition of communities.

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

Low air density causes relatively low pressure on land. Normally it is 760 mmHg. 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 respiration rate. The limits of advancement of higher plants into the mountains are approximately the same. Somewhat more hardy are arthropods (springtails, mites, spiders), which can be found on glaciers above the vegetation line.

Lecture 3 HABITAT AND THEIR CHARACTERISTICS (2 hours)

1.Aquatic habitat

2. Ground-air habitat

3. Soil as a habitat

4.Organism as a habitat

In the process of historical development, living organisms have mastered four habitats. The first is water. Life originated and developed in water for many millions of years. The second - ground-air - plants and animals arose on land and in the atmosphere and rapidly adapted to new conditions. Gradually transforming the upper layer of land - the lithosphere, they created a third habitat - soil, and themselves became the fourth habitat.

Aquatic habitat - hydrosphere

Ecological groups of hydrobionts. The warm seas and oceans (40,000 species of animals) in the equator and tropics are characterized by the greatest diversity of life; to the north and south, the flora and fauna of the seas are hundreds of times depleted. As for the distribution of organisms directly in the sea, the bulk of them are concentrated in the surface layers (epipelagic) and in the sublittoral zone. Depending on the method of movement and stay in certain layers, marine inhabitants are divided into three ecological groups: nekton, plankton and benthos.

Nekton(nektos - floating) - actively moving large animals that can overcome long distances and strong currents: fish, squid, pinnipeds, whales. In fresh water bodies, nekton includes amphibians and many insects.

Plankton(planktos - wandering, soaring) - a collection of plants (phytoplankton: diatoms, green and blue-green (fresh water bodies only) algae, plant flagellates, peridinea, etc.) and small animal organisms (zooplankton: small crustaceans, of the larger ones - pteropods mollusks, jellyfish, ctenophores, some worms) living at different depths, but not capable of active movement and resistance to currents. Plankton also includes animal larvae, forming a special group - neuston. This is a passively floating “temporary” population of the uppermost layer of water, represented by various animals (decapods, barnacles and copepods, echinoderms, polychaetes, fish, mollusks, etc.) in the larval stage. The larvae, growing up, move into the lower layers of the pelagel. Above the neuston there is a pleiston - these are organisms in which the upper part of the body grows above water, and the lower part in water (duckweed - Lemma, siphonophores, etc.). Plankton plays an important role in the trophic relationships of the biosphere, because is food for many aquatic inhabitants, including the main food for baleen whales (Myatcoceti).

Benthos(benthos – depth) – bottom hydrobionts. It is represented mainly by attached or slowly moving animals (zoobenthos: foraminephores, fish, sponges, coelenterates, worms, brachiopods, ascidians, etc.), more numerous in shallow water. In shallow water, benthos also includes plants (phytobenthos: diatoms, green, brown, red algae, bacteria). At depths where there is no light, phytobenthos is absent. Along the coasts there are flowering plants of zoster, rupiah. Rocky areas of the bottom are richest in phytobenthos.

In lakes, zoobenthos is less abundant and diverse than in the sea. It is formed by protozoa (ciliates, daphnia), leeches, mollusks, insect larvae, etc. The phytobenthos of lakes is formed by free-floating diatoms, green and blue-green algae; brown and red algae are absent.

Taking root coastal plants in lakes form clearly defined belts, the species composition and appearance of which are consistent with the environmental conditions in the land-water boundary zone. Hydrophytes grow in the water near the shore - plants semi-submerged in water (arrowhead, whitewing, reeds, cattails, sedges, trichaetes, reeds). They are replaced by hydatophytes - plants immersed in water, but with floating leaves (lotus, duckweed, egg capsules, chilim, takla) and - further - completely submerged (pondweed, elodea, hara). Hydatophytes also include plants floating on the surface (duckweed).

The high density of the aquatic environment determines the special composition and nature of changes in life-supporting factors. Some of them are the same as on land - heat, light, others are specific: water pressure (increases with depth by 1 atm for every 10 m), oxygen content, salt composition, acidity. Due to the high density of the environment, the values ​​of heat and light change much faster with an altitude gradient than on land.

Thermal mode. The aquatic environment is characterized by less heat gain, because a significant part of it is reflected, and an equally significant part is spent on evaporation. Consistent with the dynamics of land temperatures, water temperatures exhibit smaller fluctuations in daily and seasonal temperatures. Moreover, reservoirs significantly equalize the temperature in the atmosphere of coastal areas. In the absence of an ice shell, the seas have a warming effect on the adjacent land areas in the cold season, and a cooling and moistening effect in the summer.

The range of water temperatures in the World Ocean is 38° (from -2 to +36°C), in fresh water bodies – 26° (from -0.9 to +25°C). With depth, the water temperature drops sharply. Up to 50 m there are daily temperature fluctuations, up to 400 – seasonal, deeper it becomes constant, dropping to +1-3°C (in the Arctic it is close to 0°C). Since the temperature regime in reservoirs is relatively stable, their inhabitants are characterized by stenothermism. Minor temperature fluctuations in one direction or another are accompanied by significant changes in aquatic ecosystems.

Examples: a “biological explosion” in the Volga delta due to a decrease in the level of the Caspian Sea - the proliferation of lotus thickets (Nelumba kaspium), in southern Primorye - the overgrowth of whitefly in oxbow rivers (Komarovka, Ilistaya, etc.) along the banks of which woody vegetation was cut down and burned.

Due to varying degrees of heating of the upper and lower layers throughout the year, ebbs and flows, currents, and storms, constant mixing of water layers occurs. The role of water mixing for aquatic inhabitants (aquatic organisms) is extremely important, because this evens out the distribution of oxygen and nutrients inside reservoirs, ensuring metabolic processes between organisms and the environment.

In stagnant reservoirs (lakes) of temperate latitudes, vertical mixing takes place in spring and autumn, and during these seasons the temperature throughout the reservoir becomes uniform, i.e. comes homothermy. In summer and winter, as a result of a sharp increase in heating or cooling of the upper layers, the mixing of water stops. This phenomenon is called temperature dichotomy, and the period of temporary stagnation is called stagnation (summer or winter). In summer, lighter warm layers remain on the surface, located above heavy cold ones (Fig. 3). In winter, on the contrary, in the bottom layer there is more warm water, since directly under the ice the temperature of surface waters is less than +4°C and, due to the physicochemical properties of water, they become lighter than water with a temperature above +4°C. During periods of stagnation, three layers are clearly distinguished: the upper (epilimnion) with the sharpest seasonal fluctuations in water temperature, the middle (metalimnion or thermocline), in which a sharp jump in temperature occurs, and the bottom (hypolimnion), in which the temperature changes little throughout the year. During periods of stagnation, oxygen deficiency occurs in the water column - in the bottom part in summer, and in the upper part in winter, as a result of which fish kills often occur in winter.

Light mode. The intensity of light in water is greatly weakened due to its reflection by the surface and absorption by the water itself. This greatly affects the development of photosynthetic plants. The less transparent the water, the more light is absorbed. Water transparency is limited by mineral suspensions and plankton. It decreases with the rapid development of small organisms in summer, and in temperate and northern latitudes even in winter, after the establishment of ice cover and covering it with snow on top.

In the oceans, where the water is very transparent, 1% of light radiation penetrates to a depth of 140 m, and in small lakes at a depth of 2 m only tenths of a percent penetrates. Rays from different parts of the spectrum are absorbed differently in water; red rays are absorbed first. With depth it becomes darker, and the color of the water first becomes green, then blue, indigo and finally blue-violet, turning into complete darkness. Hydrobionts also change color accordingly, adapting not only to the composition of light, but also to its lack - chromatic adaptation. In light zones, in shallow waters, green algae (Chlorophyta) predominate, the chlorophyll of which absorbs red rays, with depth they are replaced by brown (Phaephyta) and then red (Rhodophyta). At great depths, phytobenthos is absent.

Plants have adapted to the lack of light by developing large chromatophores that provide low point compensation for photosynthesis, as well as an increase in the area of ​​assimilating organs (leaf surface index). For deep-sea algae, strongly dissected leaves are typical, the leaf blades are thin and translucent. Semi-submerged and floating plants are characterized by heterophylly - the leaves above the water are the same as those of land plants, they have a solid blade, the stomatal apparatus is developed, and in the water the leaves are very thin, consisting of narrow thread-like lobes.

Heterophylly: egg capsules, water lilies, arrow leaf, chilim (water chestnut).

Animals, like plants, naturally change their color with depth. In the upper layers they are brightly colored different colors, in the twilight zone (sea bass, corals, crustaceans) are painted in colors with a red tint - it is more convenient to hide from enemies. Deep-sea species lack pigments.

The characteristic properties of the aquatic environment, different from land, are high density, mobility, acidity, and the ability to dissolve gases and salts. For all these conditions, hydrobionts have historically developed appropriate adaptations.

2. Ground-air habitat

In the course of evolution, this environment was developed later than the aquatic one. Its peculiarity is that it is gaseous, therefore it is characterized by low humidity, density and pressure, and 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 on the soil or through the air (birds, insects), and plants take root in the soil. In this regard, animals developed lungs and trachea, and plants developed a stomatal apparatus, i.e. organs with which the land inhabitants of the planet absorb oxygen directly from the air. Skeletal organs have developed strongly, ensuring autonomy of movement on land and supporting the body with all its organs in conditions of insignificant environmental density, thousands of times less than water. Ecological factors in the ground-air environment differ from other habitats in the high intensity of light, significant fluctuations in temperature and air humidity, the correlation of all factors with geographic location, changing seasons and time of day. Their effects on organisms are inextricably linked with air movement and position relative to the seas and oceans and are very different from the effects in the aquatic environment (Table 1).

Habitat conditions for 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	Almost none	Large (can reach 1000 atmospheres)
Temperature	Significant (varies within very wide limits - from -80 to +1ОО°С and more)	Less than the value for the inhabitants of the air (varies much less, usually from -2 to +40°C)
Oxygen	Non-essential (mostly in excess)	Essential (often in short supply)
Suspended solids	Unimportant; not used for food (mainly minerals)	Important (food source, especially organic matter)
Dissolved substances in the environment	To some extent (only relevant in soil solutions)	Important (certain quantities required)

Land animals and plants have developed their own, no less original adaptations to unfavorable environmental factors: the complex structure of the body and its integument, the periodicity and rhythm of life cycles, thermoregulation mechanisms, etc. Targeted mobility of animals in search of food has developed, wind-borne spores, seeds and pollen, as well as plants and animals whose life is entirely connected with the air. An exceptionally close functional, resource and mechanical relationship with the soil has been formed.

Many of the adaptations were discussed above as examples in characterizing abiotic environmental factors. Therefore, there is no point in repeating ourselves now, since we will return to them in practical classes.

In the process of their historical development, living beings mastered 4 habitats: aquatic, ground-air, soil and other organisms. Each of them has characteristic features, and it is impossible to say which is more important. Let's get acquainted with the features of the ground-air habitat.

Definition

The ground-air habitat is biological environment residence of organisms located on the land surface and in low atmospheric layers.

It cannot be called the first to be mastered by living organisms, since life originated in the sea. During evolutionary development, creatures developed certain adaptations that gave them the opportunity to move to land and into the atmosphere.

Peculiarities

The most important ecological niche is the ground-air environment. Features of the environment are:

• gaseousness;
• high oxygen content;
• low humidity;
• presence of pressure and density.

This shapes the conditions in which organisms are forced to live. Also significant features of the land-air habitat are the change of seasons and seasons, temperature fluctuations, specific daylight hours, wind. To live here, living organisms had to change their anatomy, physiology and behavior, which helped them adapt. The most important (significant) environmental factors include:

• humidity;
• temperature.

Other factors have a much lesser impact on living organisms. These are pressure and density.

How did the animals adapt?

Many of known to science species of animals live precisely in the ground-air environment. Features of the environment forced them to develop several types of adaptation:

• The presence of lungs gives them the ability to breathe air.
• To move on land, the skeleton was developed.

In order to exist normally in the conditions of the land-air environment that are familiar to us, representatives of the fauna had to go through a long evolution and develop a wide range of adaptation mechanisms.

How did the plants adapt?

Most plants grow in a land-air environment. Features of the environment determined the emergence of the following adaptation mechanisms:

• The presence of roots, thanks to which plants obtain minerals and moisture from the soil.
• Thanks to stomata, representatives of the flora were able to absorb oxygen directly from the air.

Plants often have to survive in conditions of insufficient moisture, so the flora of deserts and savannas has developed its own adaptation methods: a long main root grows deep into the soil, extracting moisture from underground sources. Small, hard leaves reduce evaporation.

What other features of plant adaptation to the ground-air environment do researchers highlight?

They grow in the tundra dwarf trees and shrubs, the height of which rarely exceeds human height. The conditions here are very harsh: long winter (frost for more than 7 months a year), short cool summer. Strong winds and soil that is so frozen that it does not have time to thaw in the summer - these are the features of the environment. And plants learned to survive in them. Some species can survive snowfall while in flower, others have small leaves, which helps avoid moisture evaporation.

The influence of environmental factors on the characteristics of the inhabitants

So, the essential features of the ground-air environment had an impact on the structure and appearance of the inhabitants. Information on how this or that factor affected the flora and fauna is presented in the table.

Interaction between living organisms and the environment

	Effect on plants	Effect on animals
Air density	Appearance of roots and mechanical tissues	Formation of a dense skeleton and development of muscles, the ability of many species to fly
	Complication of metabolic processes	Ability to use the lungs and trachea
edaphic environmental factors (relief and soil composition)	The root system depends on the characteristics of the soil	The shape of the hooves depends on whether the animal is running or jumping
	Trees shed their leaves for the winter	The animals have become warm-blooded, in the northern regions they have thick fur, and they molt in the spring

As you can see, there are quite a lot of environmental factors that have a significant impact on the lives of its inhabitants. Therefore, a considerable number of adaptation mechanisms have been developed.

Edaphic factors

Let's consider how other plant and animal organisms have adapted to the characteristics of the soil and topography. First of all, the root system of many plants has changed:

• Trees growing in permafrost conditions have an extensive root system that does not go deep. Such are larches, birches, and spruces. If these same species are in a milder climate, then their roots penetrate deeper into the soil.
• Representatives of the flora growing in arid conditions have a long root capable of drawing moisture from the depths.
• If the soil is excessively wet, then pneumatophores - breathing roots - form in plants.

The soil can have a different composition, so specific species can grow on one type of soil or another:

• Nitrophils prefer nitrogen-rich soils, for example, shepherd's purse, nettle, wheatgrass, henbane.
• Halophytes (quinoa, beets, wormwood) love salty soils.
• Petrophytes (lithophytes) grow in rocky areas. These are saxifrages, junipers, pines, and bluebells.
• Quick sand is a fertile soil for psammophytes: saxaul, sand acacia, willow.

So, plants are influenced by the composition of the soil. For animals, the nature of the soil and relief are most important. Thus, ungulates need hard ground that allows them to push off while running and jumping. However, dense soil is inconvenient for burrowing animals, as it prevents them from building shelters.

The animals have also adapted well to edaphic factors ground-air environment. First of all, those species that have to run a lot have developed powerful light limbs, while others have developed hind legs and short front legs that make it possible to jump, such as hares and kangaroos.

Adaptation for flight

Birds are one of the main inhabitants of the land-air environment. Features of the environment led to the emergence of the following forms of adaptation:

• streamlined body shape;
• hollow bones help reduce the weight of the “flyer”;
• wings help stay in the air;
• Not only birds, but also some animals have the ability to fly thanks to special membranes.

All these features help representatives of the fauna take off and stay in the air.

Adaptation of organisms to changing environmental factors

The main features of the ground-air environment may change. So, in middle lane In winter it snows, and in summer it is hot. That is why living organisms often have to adapt to changing living conditions. Such adaptation mechanisms were also developed in the process of evolution.

So, plants can only develop in favorable conditions, with sufficient light and moisture. That is why their growing season is spring and summer. In winter there comes a period of rest. Nutrients necessary for survival accumulate in the roots over the summer, and trees shed their leaves, since the reduction in daylight hours makes it impossible for the leaves to form nutrients.

Animals have also developed many ways to adapt to changing environmental conditions:

• Some fall into hibernation, having previously accumulated the necessary supply of nutrients (bears).
• With the onset of cold weather, migratory birds go to hot countries in order to return to their nests in the spring and begin hatching their chicks.
• By winter, many residents of northern latitudes develop a dense undercoat, thanks to which the animal can withstand severe frosts without problems. In spring the animal moults.

Thanks to such mechanisms, it becomes clear how representatives of the plant and animal world adapt to the land-air environment of life. The features of the environment are subject to change, so both the appearance and the behavior of its inhabitants change. All these mechanisms are the result of long evolutionary development.

We examined the essential features of one of the main habitats - ground-air. All living organisms that live on the surface of the soil or in the lower layers of the atmosphere have learned to adapt to the changing features of the environment.