"General characteristics of mammals. Living environments, external structure and habitats." Mammals have now mastered different habitats Mammal animals habitat

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

Ground-air habitat is the biological habitat 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, and 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 the animal species known to science 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?

The tundra is home to dwarf trees and shrubs, the height of which rarely exceeds human height. The conditions here are very harsh: long winters (frost for more than 7 months a year), short cool summers. 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 their impact on the structure and appearance inhabitants. Information on how this or that factor affected the flora and fauna is presented in the table.

Interaction between living organisms and 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.

Animals have also adapted well to the edaphic factors of the land-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 to 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 hibernate, 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 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 characteristics of the environment.

The peculiarities of the organization of mammals allowed them to populate habitats with a wide variety of environmental conditions. Representatives of this group of vertebrates are found throughout the entire surface of the Earth, with the exception of perhaps the interior regions of Antarctica; even in its coastal areas there are seals. At the opposite pole, individual aquatic species are the same seals or narwhals, - also reach the highest latitudes, not to mention terrestrial species ( polar bears, arctic foxes And reindeer ). Other areas of the Earth with low temperatures - high mountain areas - according to some data, are temporarily or permanently inhabited by mammals up to altitudes of more than seven kilometers; to similar heights there are known cases of encounters with rams And wolves in the Himalayas, and in the lower mountain systems there are numerous representatives rodents, mountain goats, and predatory ones like snow leopard. Sperm whales same as water animals, on the contrary, are capable of diving to depths also amounting to kilometers.

If we talk about specific abiotic factors, then some species of mammals are capable of normal existence only in areas with flat and relatively constant temperature; these are hippos, rhinoceroses, monkey and other inhabitants of tropical and equatorial latitudes. Residents temperate zone, on the contrary, are able to tolerate a much larger amplitude. White hare, for example, living in Siberia, can withstand up to +35 o C in summer and -68 o C in winter; similar thresholds also exist foxes or wolves.

The temperature factor is more important for water And semi-aquatic, and soil species. Nutria, for example, can live only in areas where there is no ice on water bodies in winter. For moles the temperature factor is significant from the point of view of the depth of soil freezing; therefore, these animals are not found in Eastern Siberia.

Meaning humidity does not significantly affect the life of mammals. The exception is terrestrial species with bare skin ( hippos, buffalos) - they need a wetter climate, like the tropics. Same mole It also cannot live in dry soils - the invertebrates that serve as its food will not survive in such conditions.

In areas with a pronounced winter season, it is of great importance snow depth, from under which animals are forced to get food. For wild boar, for example, the maximum depth is about 30-40 cm, for moose it can reach up to 90 cm.

For underground or burrowing animals it is of great importance soil density- it is difficult for moles to make tunnels in too dense soil. Comb-toed jerboa lives only in shifting sands; big jerboa- on the contrary, in dense soils. Boars Soft soil is needed to more effectively search for food in it. Horses or antelopes, on the contrary, you need solid soil - the hooves are not particularly suitable for sticky soil.

It also has some significance character of the relief. Rams the terrain needs to be open, with large pastures and a distant horizon. Goats, on the contrary, need rocky landscapes.

From all of the above, there is only one conclusion: environmental conditions do not have a large direct impact on the distribution of mammals; To a greater extent, this dependence is associated with the ecological niches they occupy, the way they feed, move, behave, etc.

Habitat

Thanks to the peculiarities of their structure and physiology, mammals acquired the ability to adapt to a wide variety of living conditions and populated all terrestrial environments - ground, air, water And soil.

Terrestrial mammals

Terrestrial mammals- the most widespread ecological group of these vertebrates, inhabiting diverse landscapes almost all over the land (with the exception of the icy expanses of Antarctica). The diversity of climatic and other abiotic and biotic conditions led to diversity within this group, expressed in a large number of options for adaptability to specific living conditions.

According to habitat conditions, terrestrial mammals can be divided into three main groups, and these, in turn, into a number of subgroups

Forest mammals

These representatives of the class live in thickets of trees and large shrubs. This way of life presupposes, on the one hand, a large number of shelters and the possibility of living and foraging on several tiers, and on the other hand, very limited visibility. Three subgroups are distinguished according to their primary place of residence and foraging:

• Tree climbers
  These animals spend most of their lives in trees, which they use for movement, obtaining food, making nests and other structures for rest, reproduction and shelter from predators. These include protein, flying squirrel, monkeys, lemurs, sloths, some bears. These animals feed mainly on food plant origin: squirrels specialize in conifer seeds, monkey- on a variety of fruits, the Bears- fruits and vegetative parts of plants; predators, eating mainly animals and birds, also do not refuse plant growth. Sharp claws help move through trees ( squirrels, the Bears, martens, sloths), limbs with highly developed fingers, in which the thumb is opposed to the rest for better grasping of branches ( primates), grasping tail (some monkey, possums). Many are able to jump from one tree to another, using the leathery membrane between the front and hind limbs ( flying squirrels, woolwings) or fluffy tail ( squirrels, martens) as a tool for gliding flight. Some ( gibbons) use limbs to swing on one branch and thus jump to another; this method of movement is called brachiation. Many tree dwellers use hollows as shelters for sheltering or breeding offspring or construct them themselves from branches.
• Semi-arboreal, semi-terrestrial
  They get food and live both in trees and on the surface of the earth, these include white-breasted bear, chipmunk, sable. The first climbs trees well, from which it produces a variety of fruits or honey, and rests in nests of branches, hibernating in hollows for the winter; on the ground, in addition to fruits, it preys on invertebrates and small vertebrates (rodents). The second lives mostly on the ground, foraging for fruits, seeds or mushrooms, while often moving through trees, which it climbs quite well, but is unable to jump like squirrels due to its less fluffy tail; It usually nests in hollows or under roots. The third gets most of its food on the ground (rodents, fruits and seeds), but catches birds or squirrels in the trees; also nests in hollows or under roots
• Terrestrial forest mammals
  Living under the forest canopy, they do not climb trees and use them only as a source of food (bark, branches, etc.) or shelter; these include deer, brown bears, wolverines, moose. These animals raise their cubs either in dug holes (wolverine) or on the surface of the earth among thickets (deer).

Mammals of open spaces

As the name suggests, this group animals live in steppe, forest-steppe, desert or subpolar landscapes, devoid of tree vegetation, which fact, on the one hand, makes their habitat “open” for viewing by predators, on the other hand, presupposes a small number of natural shelters, the absence of tiers and the presence of predominantly herbaceous in the diet vegetation. According to the method of adaptation to the specified conditions, three types can be distinguished:

• "Ungulates"
  Large herbivores that eat exclusively the vegetative parts of herbaceous plants are often dry, tough and rough. The process of obtaining and eating food takes them the vast majority of their time, and in search of food or water they constantly move over vast distances. The limbs of these mammals are covered with hooves, adapted for fast running on the hard trampled soil of steppes and savannas - its speed reaches up to 45 km/h bison, 50 km/h giraffe, 80 km/h Thomson's gazelles(however, the predators hunting them wolves And cheetahs, are able to accelerate even faster). In addition to running, a way to protect themselves from predators is to live in large groups (herds) with collective protection of the cubs, which are born already fully developed and are able to follow their mother on the first day of life. These animals do not create any dwellings or shelters, living under open air; have relatively sharp vision and eyes located on the sides of the head and thus giving a wide overview of the area; their necks are more or less long, rising above the grass, while their legs are long and slender. Such animals include horses, antelope, giraffes and so on.; this also includes kangaroo, which differ only in the way they move - not by running, but by long jumps
• "Jerboas"
  Small animals with developed hind legs, allowing them to move mainly by jumping. These animals live in desert landscapes with poor vegetation and sparse population of other animals. In addition to grass, which is rare in these landscapes, they feed on bulbs, roots, and sometimes invertebrates, but they never drink and are content with the water supplied with food. They are characterized by the construction of shelters in the form of burrows in which the cubs are hatched - and therefore their pregnancy is short, and the offspring are born relatively helpless. To this kind of mammals, in addition to the actual jerboas can be attributed gerbils, sac hoppers, long-legged, jumpers, some small marsupials
• "Gophers"
  It's shallow and average size animals inhabiting various steppe and meadow landscapes with dense grass, in which they find shelter from predators and food - vegetative parts of herbaceous plants and seeds. They are incapable of running fast in dense grass; their limbs are short and their body shape is streamlined, designed for moving in burrows. They do not migrate in search of food and spend most of their lives near burrows, which are used not only as a refuge from predators and a place for raising young (who are born helpless), but also as a storage of food reserves, which they feed on during unfavorable seasons of the year, often waiting out in a state of hibernation. To these, in addition to directly gophers, include marmots, hamsters, pikas.

Mammals of mixed habitats

These animals are able to live in both forest and steppe landscapes, often moving from one type of ecosystem to another - wolves, foxes, badgers, wild boars. According to the habitat, the composition of their diet and lifestyle change. Wolves, for example, can use both dens on the surface of the earth among stones or tree roots, as well as burrows dug by them, as shelters and a place for giving birth to cubs.

Aquatic mammals

Representatives of the environmental group aquatic mammals demonstrate greater or lesser connection with aquatic ecosystems and varying degrees of adaptability to living in aquatic environment. The return of a number of mammals to the aquatic environment from which their ancestors once escaped is associated with the search, firstly, for new sources of food, and secondly, for ways to escape from predators - the second point, in particular, corresponds to a significant increase in the size of the series aquatic representatives of the class. Several “levels” can be distinguished, characterized by varying degrees of transition from completely terrestrial to completely aquatic inhabitants

• On first level There are mammals that essentially lead a terrestrial lifestyle, but differ from typical terrestrial inhabitants by living near bodies of water and by the presence in their diet of a fairly large proportion of aquatic animals or plants. An example would be mink- this predator of the mustelid family builds burrows along the banks of rivers and lakes, and feeds on near-water rodents, amphibians And fish. No visible fixtures Mammals of this group do not show any structural or physiological characteristics to the aquatic environment.
• Second level is characterized by the presence of both terrestrial and aquatic animals or plants in the diet, habitation both on land and in the aquatic environment, as well as the presence of morphological adaptations to such a lifestyle. Otter from the same family of mustelids feeds mainly on fish, sometimes amphibians, practically does not pay attention to land inhabitants, and moves away from water no more than 100-200 meters. This predator lives in burrows, which, unlike burrows minks, have an exit under water, and has external signs of adaptation to the aquatic environment: the otter’s limbs are short, with fingers connected by a membrane, the fur is thick, with sparse guard hair and dense undercoat, the ears are shortened. Semi-aquatic rodents also have a similar appearance and lifestyle - beavers, muskrats, nutria which feed on both terrestrial and aquatic vegetation, live in near-water burrows or huts, often use bodies of water as a refuge from predators, and also have highly developed sebaceous glands, which with their secretion protect the coat from getting wet. Another representative of mustelids - sea ​​otter- finally breaks with the terrestrial environment, coming onto land only for the sake of reproduction, sleep, or during a strong storm. This predator spends most of its life on the surface of the water, swimming several kilometers from the shore; The sea otter feeds on fish and shellfish, but mainly sea ​​urchins; its limbs look like flippers, with fingers connected by a continuous membrane, but it has no ears at all.
• TO third level includes carnivorous mammals of the families seal, eared seals And walruses phylogenetically related to bearish and all with the same mustelids- this is, in a way, a continuation of their departure to sea. These are completely aquatic animals, coming onto land (or ice) only for the sake of mating, reproduction and molting. The appearance of these predators is characterized by an elongated spindle-shaped body and limbs in the form of flippers, in which the fingers are connected by a continuous membrane and are often indistinguishable in appearance. Eared seals ( sea ​​lions, seals) belong to a branch that is less divorced from the land way of life - they have more or less developed fur, ears, and their hind limbs, although shifted to the back of the body, can still be used for clumsy movement on land. The real ones seals practically deprived hairline, in connection with which the function of thermal insulation in them passes to a thick layer of subcutaneous fat, these animals do not have ears, and their hind limbs serve them exclusively as a locomotor organ when swimming, but when moving on land they do not participate at all, so their movements on the shore are possible only with the participation of the front flippers, crawling and wriggling, like snakes. In addition to morphological features, all of the above aquatic animals also have physiological adaptations to the aquatic environment, expressed, in particular, in the ability to stay under water for a long time, holding their breath. This ability is ensured by a number of factors: firstly, the increased oxygen capacity of the blood, and secondly, a serious slowdown in blood flow when in water; in a seal, for example, when on land, the heart contracts 150 times per minute, while when diving and swimming - only 30. Thanks to this feature, as well as the disconnection of many organs from the blood circulation during diving (with the possible exception of the brain and heart) much lower oxygen consumption is achieved than on land.
• Last the level is characterized by complete separation from the terrestrial environment and return to the water. These mammals ( whales, dolphins, sperm whales) never, under any circumstances, climb ashore, spending their entire lives at sea. Accordingly, they are not capable of moving on land; their body takes on a streamlined shape, like the body of a fish, the forelimbs become similar to fish fins, while the hind limbs disappear completely, remaining in some only in the form of a pair of highly reduced bones pelvic girdle. The tail of these mammals acquires horizontally located blades, which is very reminiscent of the caudal fin of fish, and the fur and ears completely disappear. At the same time, the oxygen capacity of the blood increases and the sensitivity of various organs to oxygen starvation decreases, the lungs gain the ability to quickly compress and expand to quickly and completely replace air in them during a short inhalation-exhalation, and the nostrils move to the upper side of the head, which allows you to breathe without bending neck; when in water, the nostrils are tightly closed with valves, and the structure of the larynx completely isolates the airways from food - so that the presence of water or food in the mouth does not in any way interfere with the breathing process

Subterranean mammals

Underground inhabitants are recognizable by their streamlined (valve) body shape, designed to move through burrows and tunnels, short legs, often with powerful claws with which they tear the soil, and small or absent auricles, which would only complicate movement, but would not help at all improving hearing - after all, sound is transmitted much better through the ground than through the air. The eyes, as unnecessary in dark dungeons, are underdeveloped; sometimes there is no hair. Among the mammals specialized in this way are moles, mole rats, diggers, marsupial moles and some others.

The nutrition of underground inhabitants is based on other underground inhabitants - most often these are a variety of underground invertebrates ( moles) or roots, tubers and other underground parts of plants ( mole rats). Naturally, they live in burrows of varying degrees of complexity and branching - and the tunnels serve not so much as a place of residence, but rather as passages dug when searching for food. To the surface different kinds underground animals may emerge more or less often or not leave their shelters at all; Individuals and large families can live in them.

There are some differences in the method of digging holes. Moles have powerful front paws with strong claws, turned out like a spoon or an excavator bucket - with them the animal easily loosens and scoops up the soil and pushes it to the rear end of the body, after which it pushes it out of the underground passage with its front part through vertical tunnels connected to the surface, around which characteristic heaps (molehills). Mole rats They cannot boast of powerful paws; their tool is the lower pair of incisors (powerful and sharpened, like all rodents), which during digging are isolated from the mouth by a special fold of skin, so that the teeth outwardly appear to be outside the mouth. When feeding, this fold disappears and the lower incisors take a typical position for Georgians, closing with the upper ones. They dig in a similar way mole voles- only the earth is thrown to the surface by pushing with its hind paws, and the pile at the entrance to the hole takes on a curved appearance, like a dune. Naked mole rats, small in size, dig the ground and throw it out collectively, passing it along the chain.

Flying mammals

As for the few representatives of the class who have mastered the air, they have different forms and stages of flight. Initially, passive, gliding forms of flight probably arose, which in essence are nothing more than a prolonged jump - the way, for example, they jump squirrels, using outstretched limbs and a long fluffy tail as a kind of parachute, capable of holding the animal in the air for some time. Their closest relatives - flying squirrel- a leathery membrane is formed between the front and hind legs, increasing the length of soaring to 30-60 m; the aircraft is constructed in a similar way woolwings, capable of jumping over distances of over 100 m.

Among mammals, representatives of the order are capable of real, active flapping flight. bats - fruit bats And the bats. Their flight mechanism is a thin leathery membrane stretched between the highly elongated sections of the forelimbs and short hind limbs, as well as between the two hind limbs, often connecting to the tail. The shape of the wings and the general shape of the body, more or less streamlined, were improved in the course of evolution, so that among living chiropterans there are different shapes and sizes of wings and other elements of the body structure that contribute to flight in terms of efficiency.

Anatomically, bats are characterized by a number of features similar to birds - a light but strong skeleton with skull bones fused into a single formation, powerful pectoral muscles attached to the keel (protrusion of the sternum), as well as the presence in the most advanced flyers of double articulation of the humerus with the scapula, providing more varied movements of the forelimbs relative to the body.

Some bats feed directly in the air, catching and eating insects, which are caught with the help of very sensitive ears capable of distinguishing ultrasonic vibrations (about 170 kHz) - so-called echolocation; others - predominantly plant foods, in particular fruits; Some bats are pollinators, feeding on the nectar of flowering plants, others are vampires, sucking the blood of other mammals.

Food relationships

Food chain levels

More details o Levels of food chains

From an ecological point of view, mammals are classified as consumers, both first and subsequent orders; consumers of the first order Thus, they constitute a group of herbivores, the second and subsequent ones are carnivores. This division, however, is conditional, since most representatives of the class eat both plant and animal foods, and the ratio between these food sources may fluctuate depending on the season and other reasons. It is the diversity of food sources that is one of the reasons for the species diversity and distribution of mammals.

Carnivores

Carnivorous mammals consumers of the second and subsequent orders, constitute a smaller proportion of the number of species of the class, although evolutionarily this type of nutrition is primary. However, not all carnivores feed exclusively on animals - many have a mixed diet; It is the diversity of food sources that is one of the reasons for the species diversity and distribution of mammals.

Animal foods, compared to plant foods, are characterized by greater ease of digestion and higher calorie content, respectively, and less of it is required: for example, weasel weighing 60 g per day eats an average of 15 g, which is 25% of body weight. Similarly with plant foods, the amount of animal food depends on the size and, accordingly, on the metabolic level of the animal. For example, ordinary shrew weighs much less than a weasel (11 g), but eats up to 62% of its body weight per day.

Insectivores

The first mammals, obviously, were insectivores - this can be judged by the structure of the dental apparatus - and the objects of their food were terrestrial invertebrates (insects, worms, shellfish), as well as small reptiles or amphibians. Modern hedgehogs, shrews, some marsupials retained a similar food specialization, obtaining food from the surface of the earth or from shallow burrows. Some are more specialized: anteaters, lizards And echidnas, for example, feed exclusively on ants or termites, extracting them from nests using an elongated muzzle, sticky tongue and other devices. Moles moved on to extracting invertebrates from the underground strata. The bats, for the most part, catch insects in the air. Will not refuse insects either rodents or primates. The basis of nutrition toothless whales made up of marine invertebrates - plankton - which they obtain by filtering water between the plates of the whalebone.

Predatory

Group carnivorous mammals switched to feeding on larger prey - vertebrates. However, they will not refuse invertebrates, and some will not refuse plants either. The share is especially large plant food at brown or white-breasted bears- for a long time they can do without meat and eat berries, nuts, etc. Cats or White bears, on the contrary, are exclusively carnivorous. Diet brown bear may depend on the habitat: in the Far East it mostly eats fish, while in European ecosystems it eats mainly plant food.

Scavengers

The next group of carnivores are scavengers; these eat dead, partially decomposed animals. They do not disdain such food, for example, jackals; carrion makes up most of the diet hyenas.

Bloodsucking

A peculiar group of blood-sucking mammals is represented by some bats - vampires, - they feed, as you might guess, on blood

Herbivores

Herbivorous mammals, appropriate from an environmental point of view consumers first order, constitute a large proportion of the number of species in the class. The emergence of the ability to assimilate plant matter - which on Earth is much larger than animal matter - as well as the use of not only the generative parts of plants (seeds and fruits), but also vegetative ones (leaves, branches) was one of the prerequisites for the species diversity and distribution of mammals.

Plant foods, compared to animal foods, are characterized by greater difficulty of digestion and lower calorie content, respectively, and more of it is required: for example, Pennsylvanian gray vole weighing 46 g per day eats an average of 28 g, which is 61% of body weight. Similarly with animal food, the amount of plant food depends on the size and, accordingly, on the metabolic level of the animal. For example, Canadian beaver With a weight much larger than a vole (13 kg), it eats about 390 g of food per day, which is only 3% of body weight.

Granivores

Many people eat mainly seeds- these include protein feeding on seeds coniferous trees; chipmunks consuming, in addition to coniferous seeds, also legume seeds and cereal grains; mice and others. The life of such animals depends on the harvest of corresponding plants; in the case of low yields, mass death of animals, their migration to places that are more favorable in nutritional terms, or a transition to other food sources are possible. Squirrels, for example, in the absence of coniferous seeds, have to be content with buds, which contain a high content of resins that seal their teeth.

Frugivores

There are few exclusively frugivorous mammals that eat juicy fruits - these are monkey, prosimians, the bats, some rodents.

Herbivores

Herbivores include mammals that eat mainly vegetative parts of plants - stems, leaves, bark, as well as underground parts - tubers or bulbs. At the same time, they mainly feed on grass horses, goats, rams, many rodents; leaves and branches - deer, elephants, giraffes. In a number of species, the diet varies depending on the season - e.g. hares They feed mainly on grass in summer and bark in winter. Jerboas And wild boars often, and mole rats They exclusively use underground parts of plants for food. They feed on aquatic plants sirens.

Herbivores are characterized by increased complexity of the digestive organs - in particular, elongation of the intestines, the presence of a pronounced cecum and a complex multi-chambered stomach - as well as a complication of the digestive process, during which food is passed through the digestive tract twice. At the same time, ungulates are characterized by thick and mobile tongues and lips, with which they capture food, and in ruminants artiodactyls feeding on soft vegetation, the upper incisors are reduced, while in equids whose food is tougher, these teeth are preserved. Rodents, on the contrary, do not use their lips to obtain food, but their highly developed incisors.

Nectar-sucking

There are few nectar-sucking mammals with an elongated snout capable of penetrating inside the corolla and a tongue extended at the end to catch nectar - these are some the bats

The first ancestors of mammals were, in all likelihood, small insectivorous or omnivorous forms with simple teeth, short legs equipped with claws. Their lifestyle was terrestrial and arboreal. Gradually spreading, occupying more and more new habitats (new biotopes), mammals changed and differentiated into various directions. Some of them adapted to life in the ground, leading a semi-underground or completely underground lifestyle, becoming burrowing animals; others adapted to life in water and became amphibians or entirely aquatic forms, and it is possible to establish a series of transitions from floating terrestrial, otherwise amphibious, forms to pelagic marine mammals; still others occupied open land spaces: steppe, desert, etc., becoming walking, running or jumping mammals; the fourth adapted to life in the forest, becoming arboreal, climbing animals; finally, some adapted to life in the air, becoming flying animals.
Sometimes, having adapted to one environment, mammals switched to a different way of life, and they developed new adaptations. But there are certain patterns here. Mammals apparently switched to an aerial lifestyle not from terrestrial life, but from arboreal life. Arboreal forms sometimes became terrestrial and running again (many marsupials of Australia and others from placentals). But we don’t know of a single example of a mammal that had become an aquatic transitioning back to terrestrial life. Also, an animal of a pronounced burrowing or running type has never turned into a slowly moving type of walking animal.
Thus, the evolution of mammals in connection with adaptation to different habitats can be depicted as follows (see diagram):

Simultaneously with adaptation to the substrate, where the animal moves, builds a nest, and obtains food (biotopic adaptation), mammals adapted to various kinds food (trophocenotic adaptation).
These adaptations developed independently, and the character of the teeth does not necessarily coincide with the character of the limbs. For example, running (ungulates), swimming (manat, dugong) and arboreal (sloth) forms can also be herbivores.
Mammals of open habitats. Mammals that live in open places - meadows, steppes, deserts - are found in many orders: among insectivores, carnivores, rodents, marsupials; Ungulates, by their very essence, are animals of open areas and, together with rodents, make up the bulk of their population.
Mammals of open areas have special characteristic adaptations. For animals living in open areas, firstly, it is very important to be able to recognize danger from afar or see prey or food: secondly, it is very important to have fast legs in order to run away in case of danger or catch up with prey, on the one hand, and quickly move in search of food and water - on the other, or be able to hide in a safe shelter - in a hole. Finally, it is important to have a low water requirement. For animals that serve as prey for predators, it is very important to be inconspicuous. Adaptations of this kind are characteristic of mammals in open areas: savannas, meadows, steppes, semi-deserts and deserts.
Mammals of open areas, thanks to the open distances, acquired excellent vision in the struggle for existence. The giraffe (Giraffa camelopardalis) has a very broad outlook due to the fact that the front part of the body is elevated in comparison with the back. In her related okapi ( Okapia johnstoni), a forest dweller, this feature is not nearly as pronounced. We see this feature, although to a lesser extent, in a number of steppe mammals; take, for example, the bubals (Bubalus) or wildebeest (Connochaetes), horse antelopes (Hippotragus), living in open areas overgrown with low bushes. All of them have front legs longer than the back ones and their necks are stretched upward.
Other mammals, namely many rodents, stand on their hind legs and sit on their tails to survey the area, “standing in a column.” We see this in hares (Lepus), bobak (Marmotta), ground squirrels (Citellus), kangaroos (Macropus), etc.
Ability to fast movement achieved in two ways: running or jumping. Adaptation to running is expressed in the transition from plantigrade to digigrade walking, in the loss of the clavicle, in the lengthening of the metapodial part of the limb, in the development of the hooves, in the reduction in the number of fingers to two or one, in the fusion of the carpal and tarsal bones and corresponding changes in the muscles. In the morphological part, when describing the skeleton of the limbs, and in the systematic part, when describing ungulate mammals, we indicated the evolutionary paths along which adaptation to fast running took place in different groups of mammals and at different times. Among modern mammals, the most perfect running is among the equids, horses, half-donkeys, donkeys and zebras, and among the artiodactyls, antelopes and deer. Predators of open areas that catch up with prey have corresponding adaptations of their limbs. These are the fast running wolves and dogs of this family. Canidae, cheetah from the family. Felidae
Jumping as an adaptation to rapid movement is characterized by elongation of the hind limbs, especially from the metanodial part, and shortening of the forelimbs. The forelimbs initially serve only as support on the ground when running, and the hind limbs are sometimes carried forward compared to the forelimbs. Thus, in hares, the characteristic location of the track depends on the fact that the hind limbs are carried forward along the sides of the forelimbs located one behind the other. With further specialization, the forelimbs no longer take part in movement, as, for example, in jerboas, they serve only for grasping food or for digging. The tail, on the contrary, lengthens and serves as a fulcrum when standing and a rudder for quick turns when jumping.
The ability to jump develops convergently in different orders: marsupials - kangaroos, insectivores - jumpers and a number of jumping rodents. Among predators, many cats move by jumping. Those inhabitants of open places that do not run fast and are small in size hide in holes. This ability to dig holes to hide from enemies may lead, with further adaptations, to a truly underground lifestyle.
Mice, gophers, hamsters, marmots, jerboas and many other rodents leading an above-ground lifestyle hide in holes as shelter. Many voles switch to underground feeding; such are the common vole (Microtus arvalis), the social vole (M. socialis) and other voles. The Caucasian Promethean mouse (Prometheomys sehaposchnikovi) and the mole vole (Ellobius) are already typical underground inhabitants, normally feeding on underground parts of plants.
In addition to the ability to hide or run away, mammals in open areas are usually also protected by protective coloration; it is enough to point out the color of the goitered gazelle (Antilope subgutturosa) (Fig. 641), the yellow and thin-clawed gopher (Citellus fulvus and Spermophilopsis leptodactylus), gerbils (Gerbillus), etc.

Mammals of open areas have one more feature: they, as a rule, drink very little, being content with the moisture contained in their food - plants. The ability of camels to endure thirst is well known. They can drink salty and bitter water. Many antelopes and giraffes can go without drinking for a long time. Some mammals don't drink at all. The dwarf gazelle (Gazella arabica) from the Red Sea islands does not drink at all; Perhaps other gazelles don’t drink either. The yellow ground squirrel (Citellus fulvus) does not drink even when water is available; Some other ground squirrels also do not drink, for example, the thin-toed ground squirrel (Spermophilopsis leptodactylus), gerbils (Gerbillus, Rhombomys).
Mammals are burrowing and underground. Among mammals we find not only a very large number of burrowing forms, but also the most advanced specialization of the limbs in adaptation to the burrowing lifestyle.
Nai larger number burrowing mammals are represented by rodents. Among the latter, burrowing forms are present in almost all groups. And although they are often not closely related and live in different parts light, the way of life leaves the same stamp on them. Burrowing rodents include: marmots (Marmotta), ground squirrels (Citellus, Spermophilopsis), chipmunks (Tamias) and many others among the group Sciuroidea; among Myoidea: many rats (Murinae) and voles (Microtinae), mole rats (Ellobius), gerbils (Gerbillus, Rhombomys), hamsters (Cricetinae), pieds (Lagurus), mole rats (Spalax), jerboas (Dipus, Alactaga); Cape Strider (Pedetes); Old World porcupines (Hystrix) from the group Hystricomorpha; South American tuco-tuco (Ctenomys), viscacia (Viscacia) from the family. Chinchillidae and, finally, from the Lagomorpha group: rabbits (Oryctolagus cuniculus), pikas (Ochotona). These rodents often live in huge colonies, and then the whole soil is so dug up by them that it can be dangerous to ride, since the horse always falls into holes. This picture can be observed in Asia (pikas in Mongolia, gerbils in Central Asia) and in Africa (striders), and in Patagonia (Ctenomys). However, a considerable number of burrowing forms are also found in other orders of mammals. Among the marsupials in Australia, the marsupial mole (Notoryctes) digs unusually cleverly, living underground; armadillos (Dasypodidae) from edentates; Cape aardvark (Orycteropus) and steppe lizard (Manis temminckii). An African warthog (Phacochoerus) expands aardvark burrows in the African steppes. Some predators also dig: badgers (Meles), foxes, fennec foxes (Megalotis zerda) in African deserts and Cerdocyon brasiliensis in Patagonian deserts, etc.
The ability to dig holes apparently developed in mammals as an adaptation for protection from enemies and from cold and high temperature. One can note various stages in the development of this adaptation, starting from simple scraping of the earth to real burrows with various chambers: for supplies, for hatching children, etc. Burrowing mammals can be divided into two groups: those that burrow temporarily and go outside, and those that are underground , i.e. staying underground all the time. In the first case, the changes in the animal's body will be small. An example is the changes to which the organization of the rabbit, which undoubtedly originates from the hare, has undergone. The rabbit's skull is more compressed laterally; the recess for the eyes, the area where the olfactory organ and respiratory tract are located, are more compressed. But the attachment site for the masticatory and occipital muscles is more extensive. This denser and more durable structure of the rabbit’s skull in comparison with the hare’s skull is in direct connection with the fact that a rabbit, hiding from danger, throws its head into a hole: a narrow head, firmly built, is more suitable in this case. Strong jaws and teeth serve the rabbit for digging underground and gnawing roots.
There is also a difference between a rabbit and a hare in the structure of the limbs. The hare's shoulders are much longer, the forearms are thinner and are represented mainly by the ulna bones, while the radius is much less developed and moved back. In a rabbit, both bones of the forearm are almost equally strongly developed and lie in the same plane. The changes in the pika (Ochotona) went somewhat further than in the rabbit. But this animal also spends most of its time outside, and therefore the changes in organization are not too great.
Changes in organization in burrowing forms primarily affect the forelimbs, then extend to the skull, organs, senses, spine, and coloration.
An example of a burrowing animal that has become completely underground and in high degree specialized, the marsupial mole (Notoryctes typhlops) can serve. Among marsupials, this is the only animal that leads a completely underground lifestyle. The skeleton of this animal deviated greatly from what we see in other marsupials; but in many characters we see in this animal a coincidence, convergent development with burrowing forms from placental animals, especially with the South African burrowing insectivorous golden mole (Chrysochloris aureus), mole, mole rat and other underground mammals: 1) the hair is short, thick and silky; 2) the eyes are rudimentary, rudimentary: their reduction is associated with their uselessness; 3) the postorbital process in the skull (proc. postorbitalis), which provides protection to the normally developed eye, is absent; 4) the lateral occipital processes (proc. paroccipitales) are absent; usually these processes on the sides of the occipital joints serve to attach the muscles that turn the head to the side; with an underground lifestyle, these movements are absent; 5) the articular tubercles of the skull, which lie more inferiorly in marsupials, look backward, so that the skull and spine lie on the same axis, which is very helpful when digging; 6) the cranial bones fuse very early, due to which the skull receives greater strength; 7) the skull has a conical shape that penetrates into the ground more easily; 8) the anterior nasal openings are located on the underside of the pointed snout; thanks to this, earth, sand, etc. do not get into the nostrils; 9) both halves of the lower jaw are firmly fused, which increases the strength of the skull, which acts like a wedge; 10) there are ridges on the shoulder blade, which is due to the strong development of the triceps brachii muscle; 11) there is a collarbone; 12) on the humerus there is a strong ridge - the place of attachment of the digging muscles - deltoid (m. deltoideus) and pectoralis (m. pectoralis); 13) the internal hitch is strongly developed on the shoulder due to the strong development of the flexor muscles; 14) highly developed proc. olecranon of the ulna - the place of attachment of the triceps muscle (m. triceps); 15) a number of changes in the distal part of the limb: shortening of the metacarpus and fingers, stronger development of the middle fingers, strong connection of the carpal bones; 16) underground mammals do not have an external ear; the tail is reduced.
But depending on the soil in which the animal digs, differences will be observed. When digging in soft soil (for example, in a mole - Talpa), the hand expands greatly, it acts like a shovel and has a tendency to develop a sixth finger.
The forelimb of the mole is comparable to a scraping spoon, which is taken by the handle close to itself, working with the help of a short lever. On the contrary, in those forms that dig in hard ground, the hand becomes narrower; only a few fingers take part in digging, mostly the 3rd and 4th, developing at the expense of the others, as in Notoryctes and Chrysochloris. We see the same thing in mammals that tear apart the hard structures of termites, for example, in the anteater (Myrmecophaga), in the tamandua. To prevent their claws from becoming dull when walking, these animals walk, leaning on the outer edge of their feet and bending their claws.
In the mole vole (Ellobius), the incisors, which protrude strongly forward, are used for digging. With them, this animal acts like a hoe, and throws the bitten off earth out of the hole, backing away with its hind legs. To prevent soil from getting into the mouth, the hairy part of the upper and lower lip bends between the incisors and molars, and only a very small mouth opening remains, covered by hair. In those mammals that throw out the earth with their heads, the head itself changes. Thus, in the mole (Talpa), the proboscis is supported by a special cartilage (os praenasale), which, however, is flexible enough for the proboscis to act as an organ of touch. In Notoryctes there is a hard horny shield at the end of the nose; in Chrysochloris, at the anterior end of the snout there is a wide bare skin surface ending in a wedge-shaped edge flattened horizontally. There are deviations in the arrangement of the skull bones in forms that burrow with their heads; for example, the occipital part is located obliquely forward, and not vertically.
The body of burrowing mammals in cross-section is valval, rounded instead of being laterally compressed, as in other mammals, and is of equal thickness in front and behind. This is the body of a mole, a marsupial mole, a golden mole, a blind man, a mole mole; The body of those small carnivores that, without digging themselves, hunt for burrowers by climbing into holes has the same shape: the leopard, the ferret, the ermine, the weasel, etc.
Forest mammals. Not all mammals that we meet in the forest can be called forest animals by their origin. Many of them adapted to life in the forest for the second time, moving into it from open spaces, from savannas or rare shrubs, transferring there the features of their organization that were alien to the forest. These are, for example, deer (Cervus), roe deer (Capreolus), moose (Alces), wild boars (Sus), wolverines (Gulo), bears (Ursus), badgers (Meles), beavers (Castor), etc.
That deer and elk are not at all typical forest animals can be seen from the fact that they are ungulate animals, in their origin and evolution associated with open biotopes, moreover, their huge antlers greatly complicate movement in the forest; wild boars inhabit not only forests, but also reeds; bears are found in treeless mountains; wolverine - in the alpine zone; badgers are also inhabitants of steppes and deserts; beavers live along rivers in meadow floodplains if there are bushes along the banks.
Forests from tropical wilds to open forests and thickets of bushes, despite the extreme diversity in height, density and composition of vegetation, have some common features that allow them to be considered as a natural group of “closed” biotopes.
However, in terms of biotopic conditions, bush thickets are very different from forests. Shrubs rise to a small height and do not have bare trunks, but usually form a dense network of boggy branches. According to their biotopic characteristics, they are associated with grassy open spaces, where in some cases grasses are not inferior to them in growth and where subshrubs are very similar to bushes in their branching. For large and heavy mammals, such as rhinoceroses and elephants, bushes provide insufficient obstacles to movement. There is free space above the bushes, and tall mammals can view the surroundings above the bushes.
Forests are another matter. There is a special ecological niche here - tree trunks with hollows and thick branches on which their own fauna of mammals can live and on which they can climb. Movement on the ground in the forest is cramped for large animals and trees are a serious obstacle to running. The forest has a more or less pronounced multi-tiered structure, and often shrubs are part of the forest, forming a special niche. Among forests, it is advisable to identify as a separate group of biotopes those tropical forests where, thanks to exceptionally favorable climatic conditions such rich vegetation develops that the tree stand, intertwined with vines, aerial roots and planted with a huge number of epiphytes, forms a continuous green mass - wilds (hylea), on which one can only climb. There is no room for free movements on the ground; flight between trunks, vines and leaves of epiphytes is just as difficult as in the dense crowns of trees. The bulk of mammals inhabiting tropical forest wilds are climbing forms.
The changes, which are adaptations for climbing, concern mainly the limbs and tail. If at the same time the animal acquires more or less vertical position body, then the shape of the body changes. We see this change, for example, on the chest of anthropomorphic monkeys, in which, instead of the laterally compressed shape usual for walking mammals, it takes on a shape compressed from front to back.
Among lower vertebrates, amphibians and reptiles, we have seen many examples of climbing with the help of special suction devices on the underside of the phalanges, etc. In mammals, such suction organs develop rarely and are very imperfect. In hyraxes, or fat hyraxes (Hyraeoidea), bare soles, which are several elastic crumbs separated by deep grooves, are used for suction. Hyraxes are inhabitants of rocky areas, and tree hyraxes have secondarily adapted to the forest; This design of the soles helps them stay on rocks and trees. In the brownie maca (Taraius spectrum), the crumbs at the ends of the fingers are enlarged in the form of suction pads. The best developed suction organs are in bats from the genus Thyroptera from South America and Mysopoda from Madagascar, which can be called “tenacious” and “face-footed” bats. In Tyroptera and Mysopoda, the sole of the foot is completely transformed into a round sucker with a recessed inner surface, reminiscent of the suckers on the tentacles of an octopus.
A much larger number of forms among mammals have the ability to climb or cling using sharp claws. Cats, martens, bears, squirrels, bats, etc. can climb the bark of trees.
The transformation of limbs into a kind of pincers for climbing branches is found in some mammals, mainly lemurs and marsupials. In the potto lemur (Perodicticus potto), the thumb of the forelimb and both outer fingers (4th and 5th) lie on the same axis, while the 3rd finger is very poorly developed, and the 2nd exists only in the form of a small protrusion, devoid of nail In the closely related lemur loris (Stenops tardigradus), the index finger is somewhat larger." The structure of the hand of the potto is extremely similar to that of the amphibian (Phyllomedusa). In the marsupial bear, or "koala" (Phascolarctos), five-fingered limbs are adapted for grasping. On the front legs, both the inner toes can be opposed to the other three, on the hind legs the thick big toe can also be opposed, while the remaining toes are armed with sharp, long and curved claws. Similar to what the chameleon has, namely the “pincer-like” structure of the front leg, we see in ring-tailed cuscus (Phseudocliirus) Their thumb and index finger are opposed to the other three.

The third method of adaptation to a climbing lifestyle is the development of a kind of hook from the limbs, on which the animal is suspended, hanging upside down on the branches. We see this method of climbing in sloths (Bradypus), the small anteater ( Cyclopes didactylus). This method of climbing brings with it a number of changes; for example, the hair hanging down from the belly to the back in sloths and a number of changes in the skeleton of the limbs. The claws of these animals are strongly curved (the ancestors of the hanging edentates were burrowing animals, in which the lateral fingers were already reduced and strong claws developed).
The fourth method of movement in trees is that the animal moves from branch to branch, swinging. In such animals, the thumb and 5th toe usually disappear. This type of adaptation is a further development of what we saw in suspended mammals. We see this kind of climbing in some monkeys. Their thumbs and toes are reduced, and in spider monkeys (Ateles) (Fig. 642) the thumb disappears completely. In addition, with this method of climbing, the forelimbs, both the shoulder and the forearm and fingers, are greatly lengthened. Syndactyly often develops, i.e. the fingers are covered with common skin. To one degree or another, we see this in the lemur Lichanotus and one species of gibbon (Hylobates syndactylus).
In the species of chimpanzee (Anthropopithecus), orang (Simia satyrus) and gorilla (Gorilla gorilla), adaptations to this type of tree climbing are also observed, which leads to some reduction of the thumb. In this regard, a person has no such specialization. His thumb is highly developed. It follows that its ancestors did not move like gibbons or chimpanzees, but climbed slowly, using their arms as tongs; Moreover, its adaptation to such climbing did not go far, but was at the level at which it is found in the marsupial rat. Humans (Hominidae) represent an ancient branch of the anthropomorphic trunk, never strictly adapted to climbing branches, but rather to grasping and bending branches of low-growing trees and shrubs and plucking fruit.
The fifth way to climb is with a prehensile tail. In reptiles (chameleon, for example), we see a prehensile tail as a climbing tool. We also find such a tail in mammals, mainly among monkeys and marsupials in the forest wilds of South America and Australia. In America, in the small anteater (Cyclopes didactylus), in monkeys: tenacious (Ateles), howler monkeys (Mycetes), sapazhu (Cebus) and some others, in marsupials in the possum (Didelphis marsupialis). In Australia, a number of marsupials and one mouse rodent (Chiruromys) develop a prehensile tail. In the development of the prehensile tail one can find a series of stages of gradual improvement and transition from a simple tail, which serves as a support, to a tail that is bare below and equipped with transverse grooves. Such a tail can serve as a grasping organ - a “fifth hand”.
Mammals of tropical forests are especially rich in forms, where monkeys are dominant among them. Most monkeys are perfectly adapted to life in trees, where they feed mainly on fruits. Prosimians (Prosimiae) also belong to the arboreal tropical forms. Both of these orders of the superorder of primates in their origin and evolution belong to the tropical forest wilds, from where they gave birth to other biotopes. Among other orders, sloths (Bradypus) and small anteaters (Cyclopes) are completely arboreal animals. Many bats, mainly flying dogs (Megachiroptera), use trees to roost during the day. The latter eat the fruits of trees.
Many inhabitants of the tropical forest, living and moving mainly on the ground, due to the above-mentioned features of the forest wilds, are, however, able to climb trees, where they hunt for prey or take shelter at night. For example, the gorilla is too large and heavy to live in trees, but the female gorilla and children spend the night in the trees. Jaguar (Felis onca), leopard (Felis pardus), dry land (Nasua rufa) eat other, smaller mammals, climbing trees, but they also move well on the ground.
Of the mammals that stay on the ground in the tropical forest and do not climb, some make their way through the dense thicket and undergrowth, acting with their weight - such are African elephants (Elephas africanus), rhinoceroses (Rhinoceros), buffalos (Buffalus), tapirs (Tapirus) , pigs (Sus); others, smaller ones, make their way between the bushes and trees of the undergrowth, such as, for example, the smallest of the ungulates: deer (Tragulidae) in Malayan and African forests.
The most typical forest animals of the temperate zone are: the squirrel (Sciurus) and the flying squirrel (Sciuropterus volans), the dormouse (Eliomys), the mousetrap (Muscardinus), the black wolf (Glis glis), the pine marten (Martes martes), the lynx (Lynx lynx), wild cat(Felis sylvestris), sable (Martes zibellina), etc.
Flying mammals. Flying mammals undoubtedly evolved among forest forms and arose by adaptation to jumping from branch to branch, from tree to tree. And although flying mammals constitute a special order of chiroptera (Chiroptera), completely specially modified animals, among mammals of other orders we encounter forms that seem to be transitional to flying, possessing the ability of gliding flight. This is achieved in mammals by the development of skin folds stretched between the limbs on the sides and between the head and forelimbs, between the tail and hind limbs. The fold between the head, neck and forelimbs is called propatagium; between the body and both pairs of limbs the fold is called plagiopatagium, between the hind legs and tail - uropatagium and, finally, between the toes - chiropatagium. In some cases, increasing the drag surface of the parachute is achieved by greatly lengthening the hair at the edge of the skin fold.
There is a certain pattern in the development of folds, namely, the plagiopatagium appears first. If we completely ignore phylogenetic relationships and keep in mind only the degree of complexity in development, then we can create the following series with a gradual complication in the development of the ability to plan.
The squirrel (Sciurus vulgaris) should be placed in the first place at the beginning of the row. This animal spreads its limbs wide when jumping. There is no patagium yet; there are long hairs on the sides of the body, which move to the sides when jumping. The tail helps when jumping. Experiments showed that squirrels whose tails were cut off could not jump as well or far.
The next level of specialization is represented by the sifaka lemur (Propithecus). This semi-monkey jumps from a high place (from a branch obliquely downwards), raising his arms high above his head. We see a similar adaptation in a number of lemurs. The lateral folds on the sides of the body are still very weak; when jumping, the dense and long lateral hairs straighten out. The long fluffy tail serves as a steering wheel when jumping.
The monkey named Satan (Pithecia satanas), a member of the family Cebidae, has skin folds on the body, front and hind limbs. A small crease on the front of the arms is the first hint of propatagium.
In the Australian marsupial dormouse (Acrobates pygmaeus), the plagiopatagium extends between the elbow, trunk and knee and is lined with long hairs along the edge.
In the marsupial squirrel (Petauroides volans), the flight membrane on the front legs reaches the elbow, and on the hind legs it reaches the base of the big toe. This animal perfectly jumps over considerable distances and, in the full sense of the word, flies from one branch to another, from the top of a tree to the top.
In the sugar squirrel [also a marsupial (Petaurus sciureus)] the plagiopatagium is very wide and stretched between the fifth toe of the front foot and the base of the big toe of the hind foot. There is a well-developed propatagium on the anterior margin of the forelimb. The tail is long and fluffy. The animal jumps magnificently and can, jumping from a height of 10 m, reach another tree 20-30 m away.
The development of the flying squirrels from Rodentia went even further. In one genus of taguans (Pteromys), the flight membrane starts from the front legs, stretches along the sides of the body, attaches to the hind legs and from here extends in the form of a narrow fold of skin to the tail. The large fluffy tail acts as a powerful rudder when jumping. In the common flying squirrel (Sciuropterus volans) the uropatagium is very small; on the contrary, the tail is extremely expanded.
In African flying squirrels of the genus Anomalurus (Rodentia) we have two remarkable adaptations to arboreal life and gliding flight. On the underside of the base of the tail there are two rows of horny scales, which rest against the bark of trees when climbing and thus make climbing easier. The enlargement of the plagiopatagium is due to a cartilaginous rod extending from the upper end of the ulna to the edge of the parachute fold, as in Pteromys and Sciuropterus.
Finally, in the flying maquis (Galaeopithecus volans), the flight membrane begins on the neck, connects to the front legs, covers them all the way to the hand, then passes to the legs and from here goes to the tip of the tail. Thus, all parts of the body lie in this membrane except the head. A flying poppy descends from a height of 12 m onto a tree 55 m away.
Thus, adaptations to gliding flight develop in representatives of the most diverse orders and families of mammals. The series considered shows us the way in which this specialization arose. The transition to the same way of life caused the same adaptations. In this process of evolution, adaptation did not appear suddenly, but already existing features of the organization were used for it. However, only one order - the bats - developed the ability for real flight. Chiropterans are animals of the air. Here they move, here they catch their prey, here they mate. The flight membrane developed in them differently than in the forms considered so far. Just as was the case with fossil flying dinosaurs (Pterosauria) and as is the case with birds, their forelimbs carry the flying apparatus. Apparently, this is precisely the design that is necessary for real flight.
The origin of bats from insectivores is undoubtedly. We can confidently assert that the ancestors of chiropterans had adaptations for gliding flight similar to the forms described, but we, unfortunately, do not know the transitional forms that would lead to the formation of chiropterans.
The transition to an aerial lifestyle caused a number of special adaptations. The body acquires greater strength, the bones of the skull grow together, like in birds. During flight, the animal breathes intensely, and in bats the chest greatly expands, thereby increasing the cavity for the lungs; The chest bone extends far away from the spine, and the spine in this area curves upward. Powerful pectoral muscles that move the wings cause the development of a crest or keel on the sternum at the site of their attachment, as in birds. To give the sternum more support, the ribs fuse with each other, with the sternum and with the dorsal vertebrae. The gradual development of this phenomenon can be observed in various families of bats. A strong connection of the shoulder girdle with the axial skeleton is achieved with the help of a strong clavicle. The shoulder blade is highly developed. The forelimbs are elongated, especially the forearm and fingers. Lengthening of the latter is achieved by lengthening individual elements, mainly the metacarpal bones and the second phalanges. On the contrary, the nail phalanges are shortened, remaining only on the second toe in frugivores and on the big toe of the forelegs in all chiropterans. This finger plays no role in flying, is used for climbing, is not elongated and bears a sharp claw. The flying membrane also covers the hind legs. Between the latter, it is developed differently in bats. Suction discs on the foot in some species were discussed above. They help animals to hang.
Life in the air caused bats to develop an adaptation to prevent their babies from falling to the ground after birth. Before giving birth, the female is suspended not with the help of her hind legs, as usual, but with the help of her forelimbs and bends her tail with the caudal section of the flight membrane to her belly.
Thanks to this, something like a bag or cup is obtained, into which the newborn baby falls. The latter clings tightly to the mother's chest when the latter bites the umbilical cord.
Aquatic mammals. Adaptation to life in an aquatic environment is quite common among mammals. This adaptation can be either complete or partial: an animal can either completely switch to life in water or only partially, leading a dual lifestyle: both on land and on water. In the latter, the mammal can find refuge from enemies or from the heat, obtaining food for itself on land; such, for example, is the hippopotamus or hippopotamus (Hippopotamus amphibius). Or, living on land, the animal goes into the water to get food, like an otter (Lutra) hunting for fish. In both cases, the animal is an amphibian in its lifestyle. A mammal can be called an aquatic only if it spends its entire life in the water, perhaps going out onto land only to reproduce, as we see in the fur seal (Callorhinus ursinus). Purely aquatic mammals must, of course, go through the stage of amphibious mammals before becoming purely aquatic, although their history is not always clear to us.
If we count not only purely aquatic mammals, but also amphibians, we will find adaptation to water among a number of orders. Whales, sirenians and pinnipeds are essentially aquatic animals. To one degree or another, aquatic animals are from monotremes: the platypus (Ornithorhynchus paradoxus), from the order of marsupial swimmers (Chironectes minimus), from rodents: musk rat (Fiber zibethicus), beaver (Castor fiber), swamp beaver, or nutria (Myopotamus souri ), capybara (Hidroochoerus capybara), three genera of Australian mice (family Hydromyidae), etc.; from the order of insectivores: water shrew (Crossopus fodiens), muskrat (Myogale mas"chata), Tibetan water shrew (Nectogale elegans), otter shrew (Potamogale velox), long-tailed tenrecs (Limnogale); from carnivores: mink (Lutreola lutreola), otter (Lutra lutra), Kamchatka beaver (Latax lutris); among the moles there are no actual aquatic ones, except for the hippopotamus, but a number of forms live in marshy areas, along marshy banks: tapirs (Tapirus), pigs (Suidae), waterbuck (Cobus cobus) , buffalo (Buffalus) Of the fossil ungulates, the family Macrauchenidae, from the order Litopterna, was aquatic.
Partial or complete transition to an aquatic lifestyle leads to a number of adaptations. These adaptations are determined by two points: the animal must be able to swim, that is, stay and move in the water, on the one hand, and encounter as few obstacles as possible in the water, on the other.
Here we observe a very interesting phenomenon. The adaptations that we see in swimming mammals turn out to be extremely similar to the adaptations of life in water observed in swimming reptiles. Similarities in general form The bodies between the extreme members of the water-adapted series of both between ichthyosaurs and cetaceans are so large that it forced some to talk about their relationship. It goes without saying that even a superficial examination of the internal structure immediately reveals a huge difference between them: here there is only a convergence of characteristics.
The body of both becomes ridged and, in extreme cases (in dolphins), even fish-like. The outer ear becomes small and even disappears. The neck shortens and becomes inactive due to the shortening of the cervical vertebrae and their fusion (in whales). The hair is made short and silky, lubricated with sebum, so that it does not get wet (in beavers, otters, seals). Sometimes hair disappears completely (in whales and sirens), remaining to one degree or another in the fetus during uterine life. A thick layer of fat is important as protection against cooling; it also has another meaning: it reduces the specific weight of the body and eases the pressure when the animal is immersed in depth. This fat layer reaches its greatest development in whales. The extreme members of the adaptive series, some whales, have developed a dorsal fin, namely those that are fast-swimming pelagic forms. Unlike the dorsal fin of fish, this fin is not supported by skeletal parts, just like the caudal fin of whales and sirenians.
Above, in the chapter on reptiles, it was pointed out that there are two ways to propel the body in the water: with the help of legs, like a rowing boat, and with the help of a tail, acting like a steamship propeller. We find both methods in aquatic mammals (purely aquatic and amphibian).
Changes in the legs of aquatic mammals proceed in the following directions. The legs become short, the hind legs develop stronger than the front ones and move back, the toes become widely spaced, and membranes develop between them. All these characteristics are developed to varying degrees depending on the degree of adaptation to the aquatic lifestyle.
The water shrew and other swimming insectivores have long, coarse hairs on the soles and toes of the hind legs that lie close to the legs when the animals are on land; these hairs, protruding, increase the surface of the foot during swimming. In the long-tailed tenrec and the muskrat, the toes are also connected by a membrane. These membranes are present in a poorly developed state in a number of land mammals (dogs, martens), but in aquatic mammals they increase significantly in size, connecting, for example, in an otter, the fingers almost entirely. The membrane develops primarily and to a greater extent on the hind legs, which are usually stronger than the front legs, for example, in the Kamchatka beaver (Latax lutris).
In a number of swimming mammals, the emphasis when swimming is concentrated mainly on the 4th finger, which due to this becomes the longest of all, for example, in the muskrat (Myogale moschata), in the water shrew (Neomys fodiens). In amphibian mammals that swim with the help of their paws, the tail plays the role of a rudder. It is usually horizontally flat, like a beaver's. Only insectivores (muskrat, long-tailed tenrec, otter shrew) have a tail that forms a vertical plane.
The adaptations to the aquatic lifestyle of sirenians and whales go even further. Their organization represents a mass of convergent features. In both of them, the body has a spindle-shaped shape, there is no neck, and the hind limbs are reduced. The skin of the tail grows to the sides to form a horizontally located caudal fin. The forelimbs have turned into fins, the hind limbs are reduced, the hairline is reduced, but the fat layer is highly developed.
Along with the reduction of the hind limbs there is a reduction of the pelvis. It is very interesting that in cetaceans the reduction of the pelvis proceeds in the same ways as it did in the Tertiary and modern sirenians, differing only in details. The general nature of the reduction is exactly the same, despite the different origins of whales and sirens.
Despite the strong convergence in external anatomical features, there is a great difference between sirenians and whales. For the former, the adaptation did not go as far as for the latter. Although their shoulder and forearm have been shortened, they are still relatively long and mobile. Although the brush has already become a fin, it has still changed little.
Many skeletal parts of whales and sirens are connected to each other very loosely. For example, the skeleton of the chest becomes very extensible, which is of great importance in capturing large amounts of air before the whale dives into the depths. Sponginess of bones reduces specific gravity. This is also facilitated by the extreme richness of bones in fat.
The skull of most aquatic mammals, like other aquatic vertebrates, is flattened in the vertical direction, becoming low and wide. This is already visible on the otter’s skull, but even more so on the seal. The interorbital part of the skull is very narrowed, as their eyes move upward. The supraorbital processes disappear. An upward shift of the eye, as well as the nasal openings, is already observed in the hippopotamus, which spends the day submerged in water so that only the eyes and nostrils protrude above the surface of the water. In this respect, his head resembles the head of a crocodile.
Whales have gone farthest in this device. Their nasal bones are reduced to the state of small bones lying behind the nose, in the recess of the frontal bones. Thus, the nostrils appear to lie on the highest point of the head and, when raised from the water, the first appear above the surface of the latter.
Like the crocodile, the airways of whales are protected from water penetration. The hard palate is extended back with the help of the pterygoid bones that come together in the middle. At the same time, the larynx is extended due to the elongation of the thyroid cartilage into a tube and opens not into the oral cavity, but into the nasal canals, which, with the help of special muscles, soft palate can be completely isolated from the pharynx. In toothed whales (Odontoceti), the nasal passages are connected at the top into one common nasal cavity, which opens outwards with a “spray”. A complex system of valve-shaped folds reliably closes the nasal opening. The nasal openings of other aquatic mammals are closed in the same way: pinnipeds, beavers, and otter shrews. They close thanks to the plasticity of the walls, and open with the help of special muscles.
The olfactory organs of aquatic mammals become rudimentary, the olfactory epithelium disappears, the olfactory parts of the brain are reduced, and in dolphins the olfactory lobes and the olfactory nerve disappear altogether.
The ear also undergoes changes. The outer ear, as stated above, disappears; the muscles that served to move it in the land ancestors of aquatic mammals serve to close the external auditory canal in the latter. In those animals that have retained the outer ear, other devices are used to close it. The beaver has very short ears that simply close back and press tightly. In the otter, the external auditory canal is closed by a special fold of skin. In the water cutter, two folds of skin inside the auricle serve for this purpose.
Since there is high water pressure at depth, the bullae osseae of the skull of seals and especially whales become thick-walled.
Varies in aquatic mammals and eyes. In seals and whales, like in fish, the cornea becomes flat and the lens becomes spherical. Such an eye is poorly capable of normal accommodation. The latter is ensured in seals and whales by the development of a special meridionally lying muscle bundle, the contraction of which pulls the lens forward, positioning the eye for near vision. The eyes of aquatic mammals that experience significant pressure when immersed in water usually have some kind of adaptation to protect it from the latter. The sclera of seals and whales is very thick and hard, the eye muscles are very strongly developed, stronger than is necessary for the movement of the eyeball; the optic nerve is protected by a thick layer of the “wonderful network” (vessels) forming an elastic tube.
The lacrimal gland is reduced as unnecessary, since the eye is continuously washed with water. But the so-called Harderian gland reaches greater development, secreting a fatty secretion that protects the eye from harmful influence sea ​​water. The secretion of this gland in the manatee (Manatus) forms such a reliable jelly-like layer in front of the eye that even touching the cornea does not cause a reflex on its part.
Changes in whales and internal organs. The disappearance of teeth and the development of the so-called whalebone are described above. The extensibility of the lungs has also already been mentioned. The internal structure of the lungs with dense walls of pulmonary parenchyma, with cartilage around the smallest bronchi (in dolphins) is adapted to trapping large amounts of air and high internal pressure. This device allows whales and sirens to breathe trapped air for a long time. Typically, dolphins stay underwater for up to 3 minutes, and the whale (Balaenoptera) can stay underwater for 8-12 hours.
The structure of the mammary gland in whales is also an adaptation to aquatic life. Their nipples are hidden in a pocket of their skin. The large gland has a reservoir in which milk accumulates. The milk is injected into the mouth of the suckling cub using a special muscle, since the cubs cannot suck in water.

Topic: “General characteristics of mammals. Living environments, external structure and habitats.”

The purpose of the lesson: note the progressive features of the organization of Mammals, which allowed them to occupy all the main habitats.

Tasks:

Educational:

Study the general features of the class mammals;

To develop knowledge of the external structure of mammals and their habitats.

Educational:

To recall and consolidate students’ knowledge about the ecological features of various groups of mammals;

Educators:

Continue the ability to work in a group

Develop a sense of collectivism and community, aesthetic perception of the world around us.

Equipment: presentation.

Lesson type: combined.

Teaching methods: problem-based.

Forms of organizing the educational process: work in pairs, frontal

During the classes.

Org. moment.

The bell rang

The lesson begins.

Our ears are on top of our heads.

We open our eyes wider,

We listen and remember.

We don't waste a minute.

The cheerful bell rang.

We are ready to start the lesson.

Let's listen, talk,

And help each other.

Checking d/z

Look at photographs of animals. slide

What two classes can animals be divided into?

Based on what external signs did you classify these animals into the class Reptiles and the class Birds?

Updating knowledge. (Statement of a problematic question).

The teacher shows illustrations of various representatives of the class Mammals and makes riddles on the slide

I, friends, am an underground dweller

I'm a digger and a builder

I'm digging, digging, digging,

I'm building corridors everywhere,

And then I'll build a house

And I live peacefully in it.

There is a lot of power in him,

He is almost as tall as a house.

He has a huge nose, like a nose

I grew up a thousand years ago.

Touching the grass with hooves,

A handsome man walks through the forest,

Walks boldly and easily

Horns spread wide

In summer he wanders without a road

Between pines and birches,

And in winter he sleeps in a den,

Hiding your nose from the frost.

(Bear)

Get into the habit of going into the poultry house -

Red tail

Covers his tracks

What class do you think these animals belong to?

(All these animals belong to the class Mammals)

What associations do you have with the word “mammals”?

They feed on milk, highly organized animals, covered with hair, warm-blooded, these include animals.

Right. Where can you find mammals?

In water, on land, in the air, in caves, at the North Pole.

Let's formulate the topic of the lesson.

Today in the lesson we will get acquainted with animals of the Mammal class.

2. Statement of the problematic question: What progressive features of the organization of mammals allowed them to occupy all the main habitats? In order to answer the problematic question, it is necessary to study the general characteristics of the class of Mammals.

Open your notebooks, write down the date and topic of the lesson.

3. Learning new material

Open the textbook article on page 244, find and read the definition of who are mammals?

Mammals are chordates, warm-blooded animals that feed their newborns with their milk.

Let's try to give a general description of the class of Mammals.

About 5 thousand species.

Warm-blooded animals, fur.

Viviparity.

Feeding the young with milk.

Large brain (the anterior hemispheres are well developed).

Varied and complex behavior.

They have various adaptations to living conditions.

Differentiation of teeth.

Presence of an external ear.

Presence of various glands.

Now you and I can answer the problematic question

Conclusion: The progressive structural features of Mammals allowed them to occupy all the main living environments.

And now we will try together to find the answer to the question: What are the features of the external structure of mammals? Slide

The appearance and size are very diverse: from 4 cm (dwarf shrew from insectivores), to 33 m with a mass of 150 tons (blue whale) slide

The body of mammals has the same sections as other terrestrial vertebrates: head, neck, torso, tail and two pairs of limbs. Slide

The legs are not located on the sides, as in amphibians and reptiles, but under the body. Therefore, the body is raised above the ground. This expands the possibilities of using limbs. Slide

In the structure of the head, the facial and brain sections are clearly distinguishable. In front is the mouth, surrounded by soft lips. At the end of the muzzle there is a nose covered with bare skin with a pair of nasal openings. On the front sides of the head are the eyes, protected by movable eyelids, along the outer edges of which there are long eyelashes. The lacrimal glands are well developed, the secretion of which washes the eyes and has a bactericidal effect. Closer to the back of the head, above the eyes, on the sides of the head, large ears protrude, which turn towards the sound source and allow it to be directed towards the sound.

Among the animals known:

Plantigrade

Digititating

Jumping

Tree climbers

Flying

Floating.

The structural features of mammals allow them to perform a variety of movements, develop high speed when running, fly beautifully, and swim in water. This indicates the long evolution of animals and the ability to adapt to a variety of conditions. Mammals have mastered almost everything living environment: Slide

Aquatic (dolphin, fur seal, killer whale)

Ground - air (bat, fox)

Soil (mole, mole rat), and

Habitats: Slide

Ground

Woody

Underground

Air

Nutrition methods on slide

- Most mammals have developed fur, which protects them from sudden temperature changes - from cooling and overheating, protects them from mechanical damage, and gives a protective coloring. IN wool differentiate between stiffer and longer ones guard hairs and short soft hairs forming undercoat. Long and coarse hair located on the muzzle and performing a tactile function is called vibrissae. Slide. Animals shed periodically according to the seasons: the thickness and color of their fur changes. In winter, the fur is thicker, and in animals living on snow cover it becomes white. In summer, the coat is thinner and colored in protective dark tones.

The lower end of each hair is immersed in the skin, around it there is hair follicle, small muscles fit into it, so the hair can rise like a scared cat or a barking dog. At the base of the hair are sebaceous glands. Their secretion lubricates the coat, giving it elasticity, reducing the wettability and stickiness of the coat.

Mammals and reptiles are related. Which? Open your textbook to page 246 and find the answer. Slide

There are many glands in the skin of a mammal. Slide

Fill out the table slide

Consolidation

Complete the text about the external structure of mammals.

Students work independently. The tasks are completed on pieces of paper. Then a test is carried out, the children read out the texts.

The body of mammals is covered with ________________. There are _________, ________, _____________ on the head. The legs are located under _________________. Unlike other vertebrates, mammalian eyes have eyelids with ___________, and ears have outer ___________. Mammals feed their young _________________.

If you have time, work on the slides

Homework Slide

Living environments Aquatic Terrestrial Soil Aerial

Study the external structure of mammals and insert the missing words into the given text: The body of mammals is covered with _____________ and consists of the same sections as those of other vertebrates: ___________, neck, ____________, ___________ and two pairs of _________________. The ____________ and cranial sections are clearly distinguishable on the head. The mouth opening is surrounded by soft _________, and at the end of the snout there is _______. Closer to the lateral surfaces of the head there are __________, protected by movable ____________, along the outer edges of which there are long ________________.

General characteristics of mammals 4. The body is divided into head, neck, torso, paired fore and hind limbs, and tail. The limbs are located under the body, due to which it is raised above the ground, which allows the animals to move at high speed.

Underfur, or undercoat - soft, thick, short hair. Long, large, sensory hair, at the base of which there are nerve fibers that perceive contact with foreign objects. Long, strong, hard guard hairs act as organs of touch. They retain heat well, since a lot of air is trapped between this type of hair. They protect the skin from damage.

Types of skin glands in mammals Sweat Odorous Milky Sebaceous 5. The skin is relatively thick, strong and elastic, covered with hair that is good at retaining the heat generated by the body. The skin contains sebaceous, sweat, milk and odorous glands.

Mammals are warm-blooded, furry vertebrates. They give birth to live young and feed them with milk. They have a large brain with well-developed forebrain hemispheres, organs of smell, vision, and hearing. They have varied and complex behavior. These are the most highly organized vertebrates in evolutionary terms, demonstrating a huge variety of adaptations to environmental conditions. About 4 thousand modern species are known, distributed throughout to the globe and mastered all habitats.
22 The spine consists of five sections. IN cervical spine always seven vertebrae. The musculature is represented by a complex system of differentiated muscles. There is a thoraco-abdominal muscular septum, the diaphragm. Developed subcutaneous muscles ensure changes in the position of the hairline, as well as various facial expressions. Types of movement are varied: walking, running, climbing, jumping, swimming, flying. The digestive system is highly differentiated. Saliva contains digestive enzymes. In herbivorous animals, the cecum is significantly developed. Most have no cloaca. The heart is four chambered. All organs and tissues of the body are supplied with pure arterial blood. The respiratory organs of the lungs have a large respiratory surface due to the alveolar structure. In addition to the intercostal muscles, the diaphragm also participates in respiratory movements. Excretory organs: pelvic kidneys. Urine is discharged through the urethra to the outside.