Adaptation forms table. Mechanisms of plant adaptation to unfavorable environmental conditions. Adaptations to periodic environmental factors

This observation is interesting. In animals of the northern populations, all elongated parts of the body - limbs, tail, ears - are covered dense layer wool and look relatively shorter than those of the same species, but living in a hot climate.

This pattern, known as the Alain rule, applies to both wild and domestic animals.

There is a noticeable difference in the body structure of the northern fox and the fennec fox in the south, the northern boar and the wild boar in the Caucasus. Mongrel domestic dogs in Krasnodar region, large cattle local selection are distinguished by a lower live weight compared to representatives of these species, say, Arkhangelsk.

Often animals from southern populations are long-legged and long-eared. Large ears, unacceptable at low temperatures, arose as an adaptation to life in a hot zone.

And animals of the tropics have simply huge ears (elephants, rabbits, ungulates). Ears are indicative African elephant, the area of ​​which is 1/6 of the surface of the animal’s entire body. They have abundant innervation and vascularization. In hot weather, about 1/3 of the entire circulating blood passes through the circulatory system of the ear shells in an elephant. As a result of increased blood flow, excess heat is released into the external environment.

The desert hare Lapus alleni is even more impressive with its adaptive abilities to high temperatures. In this rodent, 25% of the total body surface is covered by bare ears. It is not clear what the main biological task of such ears is: to detect the approach of danger in time or to participate in thermoregulation. Both the first and second tasks are solved by the animal very effectively. The rodent has a keen ear. Developed circulatory system auricles with a unique vasomotor ability serves only thermoregulation. By increasing and restricting blood flow through the auricles, the animal changes heat transfer by 200-300%. Its hearing organs perform the function of maintaining thermal homeostasis and saving water.

Due to the saturation of the auricles with thermosensitive nerve endings and rapid vasomotor reactions from the surface of the auricles, a large number of excess thermal energy in both the elephant and especially the lepus.

Fits well into the context of the problem being discussed and the body structure of the relative modern elephants- mammoth. This northern equivalent of the elephant, judging by the preserved remains discovered in the tundra, was significantly larger than its southern relative. But the mammoth's ears had a smaller relative area and were also covered with thick hair. The mammoth had relatively short limbs and a short trunk.

Long limbs are disadvantageous in low temperature conditions, since too much thermal energy is lost from their surface. But in hot climates, long limbs are a useful adaptation. IN desert conditions camels, goats, horses of local selection, as well as sheep, cats, as a rule, long-legged.

According to N. Hensen, as a result of adaptation to low temperatures In animals, the properties of subcutaneous fat and bone marrow change. In Arctic animals, bone fat from the phalanx of the fingers has low point melting and does not freeze even in severe frosts. However, bone fat from bones that are not in contact with a cold surface, such as the femur, has the usual physicochemical properties. Liquid fat in the bones of the lower limbs provides insulation and joint mobility.

The accumulation of fat is observed not only in northern animals, for which it serves as thermal insulation and a source of energy during periods when food is unavailable due to severe bad weather. Animals living in hot climates also accumulate fat. But the quality, quantity and distribution of fat throughout the body is different in northern and southern animals. In wild Arctic animals, fat is distributed in the subcutaneous tissue evenly throughout the body. In this case, the animal forms a kind of heat-insulating capsule.

In animals temperate zone fat as a heat insulator accumulates only in species with poorly developed coats. In most cases, accumulated fat serves as a source of energy during the lean winter (or summer) period.

In hot climates, subcutaneous fat deposits bear a different physiological burden. The distribution of fat deposits throughout the body of animals is characterized by great unevenness. Fat is localized in the upper and posterior parts of the body. For example, in ungulates African savannas the subcutaneous fat layer is localized along the spine. It protects the animal from the scorching sun. The belly is completely free of fat. This also makes a lot of sense. Ground, grass or water that is colder than air ensures effective heat removal through the abdominal wall in the absence of fat. Small fat deposits in animals in hot climates are also a source of energy during periods of drought and the associated hungry existence of herbivores.

The internal fat of animals in hot and arid climates performs another extremely useful function. In conditions of lack or complete absence of water, internal fat serves as a source of water. Special studies show that the oxidation of 1000 g of fat is accompanied by the formation of 1100 g of water.

Camels, fat-tailed and fat-tailed sheep, and zebu cattle serve as examples of unpretentiousness in arid desert conditions. The mass of fat accumulated in the humps of a camel and the fat tail of a sheep is 20% of their live weight. Calculations show that a 50-kilogram fat-tailed sheep has a water supply of about 10 liters, and a camel has even more - about 100 liters. The latest examples illustrate the morphophysiological and biochemical adaptations of animals to extreme temperatures. Morphological adaptations extend to many organs. Northern animals have a large volume of the gastrointestinal tract and a large relative length of the intestines; they deposit more internal fat in the omentum and perinephric capsule.

Animals of the arid zone have a number of morphofunctional features of the urinary formation and excretion system. Back at the beginning of the 20th century. morphologists have discovered differences in the structure of the kidneys of desert animals and animals of temperate climates. In animals in hot climates, the medulla is more developed due to the enlargement of the rectal tubular part of the nephron.

For example, at African lion The thickness of the renal medulla is 34 mm, while in the domestic pig it is only 6.5 mm. The ability of the kidneys to concentrate urine is positively correlated with the length of the loop of Hendle.

In addition to structural features, functional features of the urinary system were found in animals of the arid zone. Thus, for a kangaroo rat, the pronounced ability of the bladder to reabsorb water from secondary urine is normal. In the ascending and descending channels of the loop of Hendle, urea is filtered - a process common to the nodule part of the nephron.

The adaptive functioning of the urinary system is based on neurohumoral regulation with a pronounced hormonal component. In kangaroo rats, the concentration of the hormone vasopressin is increased. Thus, in the urine of a kangaroo rat the concentration of this hormone is 50 units/ml, in a laboratory rat it is only 5-7 units/ml. In the pituitary tissue of a kangaroo rat, the content of vasopressin is 0.9 U/mg, in a laboratory rat it is three times less (0.3 U/mg). Under water deprivation, differences between animals persist, although the secretory activity of the neurohypophysis increases in both one and the other animal.

Loss of live weight during water deprivation is lower in arid animals. If a camel loses 2-3% of its live weight during a working day, receiving only low-quality hay, then a horse and a donkey under the same conditions will lose 6-8% of their live weight due to dehydration.

The temperature of the habitat has a significant impact on the structure of the skin of animals. In cold climates, the skin is thicker, the coat is thicker, and there is down. All this helps to reduce the thermal conductivity of the body surface. In animals of hot climates the opposite is true: thin skin, sparse wool, low thermal insulation properties of the skin in general.

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The grandiose inventions of the human mind never cease to amaze, there is no limit to fantasy. But what nature has been creating for many centuries surpasses the most creative ideas and designs. Nature has created more than one and a half million species of living individuals, each of which is individual and unique in its forms, physiology, adaptability to life. Examples of adaptation of organisms to the ever-changing conditions of life on the planet are examples of the wisdom of the creator and a constant source of problems for biologists to solve.

Adaptation means adaptability or habituation. This is a process of gradual rebirth of the physiological, morphological or psychological functions of a creature in a changed environment. Both individuals and entire populations undergo changes.

A vivid example of direct and indirect adaptation is the survival of flora and fauna in the zone of increased radiation around the Chernobyl nuclear power plant. Direct adaptability is characteristic of those individuals who managed to survive, get used to it and begin to reproduce, some did not stand the test and died (indirect adaptation).

Since the conditions of existence on Earth are constantly changing, the processes of evolution and adaptation in living nature are also a continuous process.

A recent example of adaptation is a change in the habitat of a colony of green Mexican aratinga parrots. Recently, they changed their usual habitat and settled in the very mouth of the Masaya volcano, in an environment constantly saturated with highly concentrated sulfur gas. Scientists have not yet provided an explanation for this phenomenon.

Types of adaptation

A change in the entire form of existence of an organism is a functional adaptation. An example of adaptation, when a change in conditions leads to mutual adaptation of living organisms to each other, is a correlative adaptation or co-adaptation.

Adaptation can be passive, when the functions or structure of the subject occur without his participation, or active, when he consciously changes his habits to match the environment (examples of people adapting to natural conditions or society). There are cases when a subject adapts the environment to suit his needs - this is objective adaptation.

Biologists divide types of adaptation according to three criteria:

• Morphological.
• Physiological.
• Behavioral or psychological.

Examples of adaptation of animals or plants in their pure form are rare; most cases of adaptation to new conditions occur in mixed species.

Morphological adaptations: examples

Morphological changes are changes in the shape of the body, individual organs, or the entire structure of a living organism that occurred during the process of evolution.

Below are morphological adaptations, examples from animal and flora, which we consider as a matter of course:

• Degeneration of leaves into spines in cacti and other plants of arid regions.
• Turtle shell.
• Streamlined body shapes of inhabitants of reservoirs.

Physiological adaptations: examples

A physiological adaptation is a change in a number of chemical processes occurring inside the body.

• The release of a strong odor by flowers to attract insects contributes to dust.
• The state of suspended animation that simple organisms are capable of entering allows them to maintain vital activity after many years. The oldest bacteria capable of reproducing is 250 years old.
• Accumulation of subcutaneous fat, which is converted into water, in camels.

Behavioral (psychological) adaptations

Examples of human adaptation are more related to the psychological factor. Behavioral characteristics are common to flora and fauna. Thus, in the process of evolution, changes in temperature conditions cause some animals to hibernate, birds to fly south to return in the spring, trees to shed their leaves and slow down the movement of sap. The instinct to choose the most suitable partner for procreation drives the behavior of animals during the mating season. Some northern frogs and turtles freeze completely during the winter and thaw and come to life when the weather gets warmer.

Factors driving the need for change

Any adaptation process is a response to environmental factors that lead to change environment. Such factors are divided into biotic, abiotic and anthropogenic.

Biotic factors are the influence of living organisms on each other, when, for example, one species disappears, which serves as food for another.

Abiotic factors are changes in the surrounding inanimate nature, when the climate, soil composition, water supply, and solar activity cycles change. Physiological adaptations, examples of the influence of abiotic factors are equatorial fish that can breathe both in water and on land. They have adapted well to conditions where drying up of rivers is a common occurrence.

Anthropogenic factors are the influence of human activity that changes the environment.

Adaptations to the environment

• Illumination. In plants, these are separate groups that differ in their need for sunlight. Light-loving heliophytes live well in open spaces. In contrast to them are sciophytes: plants of forest thickets that feel good in shaded places. Among the animals there are also individuals that are designed for an active lifestyle at night or underground.
• Air temperature. On average, for all living things, including humans, the optimal temperature environment is considered to be from 0 to 50 o C. However, life exists in almost all climatic regions of the Earth.

Contrasting examples of adaptation to abnormal temperatures are described below.

Arctic fish do not freeze thanks to the production of a unique antifreeze protein in the blood, which prevents the blood from freezing.

The simplest microorganisms have been found in hydrothermal vents, where the water temperature exceeds boiling degrees.

Hydrophyte plants, that is, those that live in or near water, die even with a slight loss of moisture. Xerophytes, on the contrary, are adapted to live in arid regions and die in high humidity. Among animals, nature has also worked to adapt to aquatic and non-aquatic environments.

Human adaptation

Man's ability to adapt is truly enormous. The secrets of human thinking are far from fully revealed, and the secrets of people's adaptive ability will remain a mysterious topic for scientists for a long time. The superiority of Homo sapiens over other living beings lies in the ability to consciously change their behavior to suit the demands of the environment or, conversely, the world around them to suit their needs.

The flexibility of human behavior manifests itself every day. If you give the task: “give examples of people’s adaptation,” most begin to recall exceptional cases of survival in this rare cases, and in new circumstances it is characteristic of a person every day. We try on a new environment at the moment of birth, in kindergarten, school, in a team, or when moving to another country. It is this state of acceptance of new sensations by the body that is called stress. Stress is a psychological factor, but nevertheless, many physiological functions change under its influence. In the case when a person accepts a new environment as positive for himself, the new state becomes habitual, otherwise stress threatens to become protracted and lead to a number of serious diseases.

Human coping mechanisms

There are three types of human adaptation:

• Physiological. The simplest examples are acclimatization and adaptation to changes in time zones or daily work patterns. In the process of evolution, they formed Various types people, depending on their territorial place of residence. Arctic, alpine, continental, desert, equatorial types differ significantly in physiological indicators.
• Psychological adaptation. This is the ability of a person to find moments of understanding with people of different psychotypes, in a country with a different level of mentality. It is common for a reasonable person to change his established stereotypes under the influence of new information, special occasions, stress.
• Social adaptation. A type of addiction that is unique to humans.

All adaptive types are closely related to each other; as a rule, any change in habitual existence causes in a person the need for social and psychological adaptation. Under their influence, mechanisms of physiological changes come into play, which also adapt to new conditions.

This mobilization of all body reactions is called adaptation syndrome. New reactions of the body appear in response to sudden changes in the environment. At the first stage - anxiety - there is a change in physiological functions, changes in the functioning of metabolism and systems. Next, protective functions and organs (including the brain) are activated and begin to turn on their protective functions and hidden capabilities. The third stage of adaptation depends on individual characteristics: a person either becomes involved in new life and goes back to normal (in medicine, recovery occurs during this period), or the body does not accept stress, and the consequences take on a negative form.

Phenomena of the human body

Nature has a huge reserve of strength in man, which is used in Everyday life only to a small extent. It manifests itself in extreme situations and is perceived as a miracle. In fact, the miracle lies within us. Example of adaptation: the ability of people to adapt to normal life after removal of a significant part of the internal organs.

Natural innate immunity throughout life can be strengthened by a number of factors or, conversely, weakened by an incorrect lifestyle. Unfortunately, passion bad habits- This is also the difference between humans and other living organisms.

Basically, adaptation systems in one way or another relate to the cold, which is quite logical - if you manage to survive in a deep minus, other dangers will not be so terrible. The same, by the way, applies to extreme high temperatures. Those who are able to adapt will most likely not disappear anywhere.

Arctic hare are the largest hares North America, who for some reason have relatively short ears. This is a great example of what an animal can sacrifice to survive in harsh environments - although long ears can help hear a predator, short ones reduce the return of precious heat, which is much more important for arctic hare.

Frogs from Alaska of the species Rana sylvatica, perhaps, even surpassed Antarctic fish. They literally freeze into the ice in winter, thus waiting out the cold season, and come back to life in the spring. Such “cryosleep” is possible for them thanks to special structure the liver, which doubles in size during hibernation, and the complex biochemistry of the blood.

Some species of mantises, unable to spend days in the sun, cope with the lack of heat through chemical reactions in their own bodies, concentrating bursts of heat internally for short-term warmth.

A cyst is a temporary form of existence of bacteria and many single-celled organisms, in which the body surrounds itself with a dense protective shell to protect itself from the aggressive external environment. This barrier is very effective - in some cases it can help the owner survive for a couple of decades.

Nototheniform fish live in waters of Antarctica that are so cold that ordinary fish would freeze to death there. Sea water freezes only at a temperature of -2°C, which cannot be said about completely fresh blood. But Antarctic fish secrete a natural antifreeze protein that prevents ice crystals from forming in the blood - and survive.

Megathermy is the ability to generate heat using body mass, thereby surviving in cold conditions even without antifreeze in the blood. Some use it sea ​​turtles, remaining mobile when the water around almost freezes.

When migrating across the Himalayas, Asian bar-headed geese rise to enormous heights. The highest flight of these birds was recorded at an altitude of 10 thousand meters! Geese have complete control over their body temperature, even changing it if necessary. chemical composition blood to survive in the icy and thin air.

Mudskippers are not the most common type of fish, although they are fairly commonplace gobies. At low tide, they crawl through the mud, getting food for themselves, sometimes climbing trees. In their way of life, mudskippers are much closer to amphibians, and only fins with gills reveal them as fish.

Behavioral adaptations - these are behaviors developed in the process of evolution of individuals that allow them to adapt and survive in specific environmental conditions.

Typical example- winter dream of a bear.

Examples can also be 1) creation of shelters, 2) movement in order to select optimal temperature conditions, especially in extreme temperatures. 3) the process of tracking and pursuing prey in predators, and in victims - in operational responses (for example, hiding).

common for animals way of adapting to unfavorable periods- migration (saiga antelopes annually go for the winter to the southern semi-deserts with little snow, where winter grasses are more nutritious and accessible due to the dry climate. However, in the summer, semi-desert grass stands quickly burn out, so for the breeding season saigas move to the wetter northern steppes).

Examples: 4) behavior when searching for food and a sexual partner, 5) mating, 6) feeding offspring, 7) avoiding danger and protecting life in case of threat, 8) aggression and threatening postures, 9) caring for the offspring, which increases the likelihood of survival of the cubs, 10) joining in packs, 11) simulating injury or death in the event of a threat of attack.

21.Life forms as a result of the adaptation of organisms to the action of a complex of environmental factors. Classification of life forms of plants according to K. Raunkier, I.G. Serebryakov, animals according to D.N. Kashkarov.

The term “life form” was introduced in the 80s by E. Warming. He understood life form as “the form in which the vegetative body of the plant (individual) is in harmony with external environment throughout his entire life, from the cradle to the grave, from seed to death.” This is a very deep definition.

Life forms as types of adaptive structures demonstrate 1) a variety of ways of adaptation of different plant species even to the same conditions,

2) the possibility of similarity of these pathways in completely unrelated plants belonging to different types, genera, families.

->The classification of life forms is based on the structure of vegetative organs and reflects the convergent paths of ecological evolution.

According to Raunkier: applied his system to elucidate the relationship between plant life forms and climate.

He identified an important feature that characterizes the adaptation of plants to endure unfavorable seasons - cold or dry.

This feature is the position of the renewal buds on the plant in relation to the level of the substrate and snow cover. Raunkier linked this to protecting the kidneys during unfavorable times of the year.

1)phanerophytes- the buds hibernate or endure the dry period "open", high above the ground (trees, shrubs, woody vines, epiphytes).

-> they are usually protected by special bud scales, which have a number of devices to preserve the growth cone and young leaf primordia enclosed in them from moisture loss.

2)chamephytes- the buds are located almost at the level of the soil or not higher than 20-30 cm above it (shrubs, semi-shrubs, creeping plants). In cold and dead climates, these kidneys very often receive additional protection in winter, in addition to their own kidney scales: they hibernate under the snow.

3)cryptophytes- 1) geophytes - buds are located in the ground at a certain depth (they are divided into rhizomatous, tuberous, bulbous),

2) hydrophytes - buds overwinter under water.

4)hemicryptophytes- usually herbaceous plants; their renewal buds are at the soil level or are buried very shallowly, in the litter formed by leaf litter - another additional “cover” for the buds. Among the hemicryptophytes, Raunkier distinguishes “ irotogeiicryptophytes» with elongated shoots that die annually to the base, where renewal buds are located, and rosette hemicryptophytes, in which shortened shoots can overwinter entirely at the soil level.

5)therophytes- special group; these are annuals in which all vegetative parts die off by the end of the season and there are no overwintering buds left - these plants are renewed the next year from seeds that overwinter or survive a dry period on or in the soil.

According to Serebryakov:

Using and generalizing those proposed in different time class, he proposed calling a unique habitus a life form - (character form, appearance org-ma) specific groups of plants that arise as a result of growth and development in specific conditions - as an expression of adaptability to these conditions.

The basis of its classification is a sign of the life span of the entire plant and its skeletal axes.

A. Woody plants

1.Trees

2.Shrubs

3. Shrubs

B. Semi-woody plants

1.Subshrubs

2.Subshrubs

B. Terrestrial herbs

1.Polycarpic herbs (perennial herbs, bloom many times)

2.Monocarpic herbs (live for several years, bloom once and die)

G. Aquatic herbs

1.Amphibian grasses

2.Floating and underwater grasses

The life form of a tree turns out to be an adaptation to the most favorable conditions for growth.

IN forests humid tropics - most tree species (up to 88% in the Amazon region of Brazil), and in the tundra and highlands there are no real trees. In area taiga forests trees are represented by only a few species. No more than 10–12% of the total number of species are trees and in the flora of the temperate forest zone of Europe.

According to Kashkarov:

I. Floating forms.

1. Purely aquatic: a) nekton; b) plankton; c) benthos.

2. Semi-aquatic:

a) diving; b) not diving; c) only those that extract food from water.

II. Burrowing forms.

1. Absolute diggers (spending their entire lives underground).

2.Relative excavators (coming to the surface).

III. Ground forms.

1. Those who do not make holes: a) running; b) jumping; c) crawling.

2. Making holes: a) running; b) jumping; c) crawling.

3. Animals of the rocks.

IV. Woody climbing forms.

1. Not coming down from trees.

2.Only those who climb trees.

V. Air forms.

1. Foraging for food in the air.

2.Looking for food from the air.

The external appearance of birds significantly reveals their association with habitat types and the nature of their movement when obtaining food.

1) woody vegetation;

2) open spaces of land;

3) swamps and shallows;

4) water spaces.

In each of these groups there are specific forms:

a) obtain food by climbing (pigeons, parrots, woodpeckers, passerines)

b) foraging for food in flight (long-winged birds, in forests - owls, nightjars, over water - tubenoses);

c) feeding while moving on the ground (in open spaces - cranes, ostriches; forest - most chickens; in swamps and shallows - some passerines, flamingos);

d) obtaining food by swimming and diving (loons, copepods, geese, penguins).

22. The main environments of life and their characteristics: ground-air and water.

Ground-air- most animals and plants live there.
It is characterized by 7 main abiotic factors:

1.Low air density makes it difficult to maintain the shape of the body and provokes an image of the support system.

EXAMPLE: 1. Aquatic plants do not have mechanical tissues: they appear only in terrestrial forms. 2. Animals must have a skeleton: a hydroskeleton (in roundworms), or an external skeleton (in insects), or an internal skeleton (in mammals).

The low density of the environment facilitates the movement of animals. Many terrestrial species are capable of flight.(birds and insects, but there are also mammals, amphibians and reptiles). Flight is associated with searching for prey or settling. The inhabitants of the land spread only on the Earth, which serves as their support and place of attachment. In connection with active flight in such organisms modified forelimbs And pectoral muscles are developed.

2) Mobility air masses

*Provides the existence of aeroplankton. It includes pollen, seeds and fruits of plants, small insects and arachnids, spores of fungi, bacteria and lower plants.

This ecological group of org-in adapted due to the large variety of wings, outgrowths, cobwebs, or due to very small sizes.

* method of pollination of plants by wind - anemophily- har-n for birch, spruce, pine, nettle, cereals and sedges.

*dispersal by wind: poplar, birch, ash, linden, dandelion, etc. The seeds of these plants have parachutes (dandelions) or wings (maple).

3) Low pressure, norm=760 mm. Pressure differences, compared with aquatic habitats, are very small; Thus, at h=5800 m it is only half of its normal value.

=>almost all land inhabitants are sensitive to strong pressure changes, i.e. they are stenobionts in relation to this factor.

Upper limit life for most vertebrates -6000 m, because pressure decreases with altitude, which means that the solubility of o in the blood decreases. To maintain a constant concentration of O 2 in the blood, the respiratory rate must increase. However, we exhale not only CO2, but also water vapor, so frequent breathing should invariably lead to dehydration of the organism. This simple dependence is not characteristic only for rare species organisms: birds and some invertebrates, mites, spiders and springtails.

4) Gas composition has a high content of O 2: it is more than 20 times higher than in the aquatic environment. This allows animals to have a very high metabolic rate. Therefore, only on land could arise homeothermicity- the ability to maintain a constant t of the body due to internal energy. Thanks to homeothermy, birds and mammals can maintain vital activity in the harshest conditions

5) Soil and terrain are very important, first of all, for plants. For animals, the structure of the soil is more important than its chemical composition.

*For ungulates that perform long migrations on dense ground, adaptation is a decrease in the number of fingers and a => decrease in the amount of support.

*Inhabitants of quicksand typically require an increase in the support surface (fan-toed gecko).

*Soil density is also important for burrowing animals: prairie dogs, marmots, gerbils and others; some of them develop digging limbs.

6) Significant water shortage on land provokes the development of various adaptations aimed to save water in the body:

Development of respiratory organs capable of absorbing O2 from the air of the integument (lungs, trachea, pulmonary sacs)

Development of waterproof covers

The change will highlight the system and metabolic products (urea and uric acid)

Internal fertilization.

In addition to providing water, precipitation also plays an ecological role.

*Snow reduces temperature fluctuations to a depth of 25 cm. Deep snow protects plant buds. For black grouse, hazel grouse and tundra partridges, snowdrifts are a place to spend the night, that is, at 20–30 o frost at a depth of 40 cm, it remains ~0 ° C.

7) Temperature more variable than aquatic. ->many land dwellers eurybiont to this factor, i.e., beings are capable of a wide range of t and demonstrate very various ways thermoregulation.

Many species of animals that live in areas with snowy winters molt in the fall, changing the color of their fur or feathers to white. Perhaps this seasonal molting of birds and animals is also an adaptation - camouflage coloring, which is typical for the snowshoe hare, weasel, arctic fox, tundra partridge and others. However, not all white animals change color seasonally, which reminds us of the indefinability and impossibility of considering all properties of the body as beneficial or harmful.

Water. Water covers 71% of the earth's S or 1370 m3. The main mass of water is in the seas and oceans – 94-98%, in polar ice contains about 1.2% water and a very small proportion - less than 0.5%, in fresh waters of rivers, lakes and swamps.

The aquatic environment is home to about 150,000 species of animals and 10,000 plants, which is only 7 and 8% of the total number of species on Earth. Thus, evolution on land was much more intense than in water.

In the seas and oceans, as in the mountains, it is expressed vertical zoning.

All inhabitants aquatic environment can be divided into three groups.

1) Plankton- countless accumulations of tiny organisms that cannot move on their own and are carried by currents in the upper layer of sea water.

It consists of plants and living organisms - copepods, eggs and larvae of fish and cephalopods, +unicellular algae.

2) Nekton- a large number of organizations floating freely in the depths of the world's oceans. The largest of them are blue whales And giant shark feeding on plankton. But among the inhabitants of the water column there are also dangerous predators.

3) Benthos- inhabitants of the bottom. Some deep sea inhabitants lack organs of vision, but most can see in dim light. Many inhabitants lead an attached lifestyle.

Adaptations of hydrobionts to high water density:

Water has high density (800 times the density of air) and viscosity.

1) Plants have very poorly developed or absent mechanical tissues“The water itself is their support. Most are characterized by buoyancy. Har-no active vegetative propagation, the development of hydrochory - the removal of flower stalks above the water and the distribution of pollen, seeds and spores by surface currents.

2) The body has a streamlined shape and is lubricated with mucus, which reduces friction when moving. Developed devices to increase buoyancy: accumulations of fat in tissues, swim bladders in fish.

Passively swimming animals have outgrowths, spines, appendages; the body is flattened, and skeletal organs are reduced.

Different ways movement: bending of the body, with the help of flagella, cilia, reactive mode of movement (cephalomolluscs).

In benthic animals, the skeleton disappears or is poorly developed, body size increases, vision reduction is common, and tactile organs develop.

Adaptations of hydrobionts to water mobility:

Mobility is caused by ebbs and flows, sea currents, storms, at different levels elevation marks of river beds.

1) In flowing waters, plants and animals are firmly attached to stationary underwater objects. The bottom surface is primarily a substrate for them. These are green and diatom algae, water mosses. From animals - gastropods, barnacles + hide in crevices.

2) Different body shapes. Fish that live in flowing waters have a round body in diameter, while fish that live near the bottom have a flat body.

Adaptations of hydrobionts to water salinity:

Natural bodies of water have a certain chemical composition. (carbonates, sulfates, chlorides). In fresh water bodies, the salt concentration is not >0.5 g/, in the seas - from 12 to 35 g/l (ppm). With a salinity of more than 40 ppm, the reservoir is called g hyperhaline or oversalted.

1) *IN fresh water(hypotonic environment) osmoregulation processes are well expressed. Hydrobionts are forced to constantly remove water that penetrates them, they homoiosmotic.

*In salt water (isotonic environment), the concentration of salts in the bodies and tissues of hydrobionts is the same as the concentration of salts dissolved in water - they poikiloosmotic. ->inhabitants of salt water bodies have not developed osmoregulatory functions, and they were unable to populate fresh water bodies.

2) Aquatic plants are able to absorb water and nutrients from water - “broth”, the entire surface Therefore, their leaves are strongly dissected and their conducting tissues and roots are poorly developed. The roots serve to attach to the underwater substrate.

Typically marine and typically freshwater species - stenohaline, cannot tolerate changes in water salinity. Euryhaline species A little. They are common in brackish waters (pike, bream, mullet, coastal salmon).

Adaptation of hydrobionts to the composition of gases in water:

In water O2 is the most important environmental factor. Its source is the atmosphere and photosynthetic plants.

When stirring the water and decreasing t, the O2 content increases. *Some fish are very sensitive to O2 deficiency (trout, minnow, grayling) and therefore prefer cold mountain rivers and streams.

*Other fish (crucian carp, carp, roach) are unpretentious to O2 content and can live at the bottom of deep reservoirs.

*Many aquatic insects, mosquito larvae, and pulmonate mollusks are also tolerant of the O2 content in water, because from time to time they rise to the surface and swallow fresh air.

There is enough carbon dioxide in water - almost 700 times more than in air. It is used in plant photosynthesis and goes into the formation of calcareous skeletal structures of animals (mollusk shells).

Adaptations (devices)

Biology and genetics

Relative character adaptations: corresponding to a specific habitat, adaptations lose their significance when it changes; when winter is delayed or when there is a thaw in early spring, it is noticeable against the background of arable land and trees; aquatic plants when water bodies dry up, they die, etc. Examples of adaptation Type of adaptation Characteristics of adaptation Examples Special shape and structure of the body Streamlined body shape gills fins Pinniped fish Protective coloration Can be solid or dismembered; is formed in organisms living openly and makes them invisible...

Adaptations

Adaptation (or adaptation) is a complex of morphological, physiological, behavioral and other characteristics of an individual, population or species that ensures success in competition with other individuals, populations or species and resistance to environmental factors.

■ Adaptation is the result of the action of evolutionary factors.

The relative nature of adaptation: corresponding to a specific habitat, adaptations lose their significance when it changes (the white hare, when winter is delayed or during a thaw, is noticeable in early spring against the background of arable land and trees; aquatic plants die when water bodies dry out, etc.).

Examples of adaptation