Mimicry as a form of adaptation is characterized. Morphological adaptations of animals

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The textbook is addressed to 11th grade students and is designed to teach the subject 1 or 2 hours a week.

Modern design, multi-level questions and tasks, additional information and the possibility of parallel work with an electronic application contribute to the effective assimilation of educational material.

Rice. 33. Winter coloring of a hare

So, as a result of the action driving forces evolution, organisms develop and improve adaptations to conditions environment. Establishment in isolated populations various adaptations may eventually lead to the formation of new species.

Review questions and assignments

1. Give examples of the adaptation of organisms to living conditions.

2. Why do some animals have bright, unmasking colors, while others, on the contrary, have protective colors?

3. What is the essence of mimicry?

4. Does natural selection apply to animal behavior? Give examples.

5. What are the biological mechanisms for the emergence of adaptive (hiding and warning) coloration in animals?

6. Are physiological adaptations factors that determine the level of fitness of the organism as a whole?

7. What is the essence of the relativity of any adaptation to living conditions? Give examples.

Think! Do it!

1. Why is there no absolute adaptation to living conditions? Give examples that prove the relative nature of any device.

2. Boar cubs have a characteristic striped coloring, which disappears with age. Give similar examples of color changes in adults compared to offspring. Can this pattern be considered common to the entire animal world? If not, then for which animals and why is it characteristic?

3. Gather information about animals with warning colors that live in your area. Explain why knowledge of this material is important for everyone. Make an information stand about these animals. Give a presentation on this topic to primary school students.

Working with a computer

Refer to the electronic application. Study the material and complete the assignments.

Repeat and remember!

Human

Behavioral adaptations are innate, unconditional reflex behavior. Innate abilities exist in all animals, including humans. A newborn baby can suck, swallow and digest food, blink and sneeze, react to light, sound and pain. These are examples unconditioned reflexes. Such forms of behavior arose in the process of evolution as a result of adaptation to certain, relatively constant environmental conditions. Unconditioned reflexes are inherited, so all animals are born with a ready-made complex of such reflexes.

Each unconditioned reflex occurs in response to a strictly defined stimulus (reinforcement): some - to food, others - to pain, others - to the appearance of new information etc. The reflex arcs of unconditioned reflexes are constant and pass through the spinal cord or brain stem.

One of the most complete classifications of unconditioned reflexes is the classification proposed by Academician P. V. Simonov. The scientist suggested dividing everything unconditioned reflexes into three groups, differing in the characteristics of the interaction of individuals with each other and with the environment. Vital reflexes(from Latin vita - life) are aimed at preserving the life of the individual. Failure to comply with them leads to the death of the individual, and implementation does not require the participation of another individual of the same species. This group includes food and drinking reflexes, homeostatic reflexes (maintaining a constant body temperature, optimal frequency breathing, heartbeat, etc.), defensive, which, in turn, are divided into passive-defensive (running away, hiding) and active-defensive (attacking a threatening object) and some others.

TO zoosocial, or role-playing reflexes include those variants of innate behavior that arise during interaction with other individuals of their own species. These are sexual, child-parent, territorial, hierarchical reflexes.

The third group is self-development reflexes. They are not related to adaptation to a specific situation, but seem to be directed to the future. These include exploratory, imitative and playful behavior.

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

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

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

Some species of mantises, unable to stay in the sun all day, cope with the problem of lack of heat with the help of chemical reactions in your own body, concentrating flashes of heat inside for short-term heating.

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

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

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

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

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

In the process of evolution, as a result of natural selection and the struggle for existence, adaptations of organisms to certain living conditions arise. Evolution itself is essentially a continuous process of formation of adaptations, occurring according to the following scheme: intensity of reproduction -> struggle for existence -> selective death -> natural selection -> fitness.

Adaptations affect different sides life processes of organisms and therefore can be of several types.

Morphological adaptations

They are associated with changes in body structure. For example, the appearance of membranes between the toes in waterfowl (amphibians, birds, etc.), thick fur in northern mammals, long legs and a long neck in wading birds, a flexible body in burrowing predators (for example, weasels), etc. In warm-blooded animals, when moving north, an increase in average body size is observed (Bergmann's rule), which reduces the relative surface area and heat transfer. Benthic fish develop a flat body (rays, flounder, etc.). In plants in northern latitudes and in high mountainous regions, creeping and cushion-shaped forms are common, less damaged by strong winds and better warmed by the sun in the soil layer.

Protective coloration

Protective coloration is very important for animal species that do not have effective means protection from predators. Thanks to it, animals become less noticeable in the area. For example, female birds hatching eggs are almost indistinguishable from the background of the area. Bird eggs are also colored to match the color of the area. Have a patronizing connotation bottom fish, most insects and many other animal species. In the north, white or light colors are more common, helping to camouflage in the snow ( polar bears, polar owls, arctic foxes, baby pinnipeds - squirrels, etc.). A number of animals have acquired a coloration formed by alternating light and dark stripes or spots, making them less noticeable in bushes and dense thickets (tigers, young wild boars, zebras, sika deer, etc.). Some animals are capable of changing color very quickly depending on conditions (chameleons, octopuses, flounder, etc.).

Disguise

The essence of camouflage is that the shape of the body and its color make animals look like leaves, twigs, branches, bark or thorns of plants. Often found in insects that live on plants.

Warning or threatening coloring

Some types of insects that have poisonous or odorous glands have bright warning colors. Therefore, predators that once encounter them remember this coloring for a long time and no longer attack such insects (for example, wasps, bumblebees, ladybugs, Colorado potato beetles and a number of others).

Mimicry

Mimicry is the coloring and body shape of harmless animals that imitate their poisonous counterparts. For example, some don't poisonous snakes look like poisonous ones. Cicadas and crickets resemble large ants. Some butterflies have large spots on their wings that resemble the eyes of predators.

Physiological adaptations

This type of adaptation is associated with a restructuring of metabolism in organisms. For example, the emergence of warm-bloodedness and thermoregulation in birds and mammals. In simpler cases, this is an adaptation to certain forms of food, the salt composition of the environment, high or low temperatures, humidity or dryness of soil and air, etc.

Biochemical adaptations

Behavioral adaptations

This type of adaptation is associated with changes in behavior in certain conditions. For example, caring for offspring leads to better survival young animals and increases the stability of their populations. IN mating seasons many animals form separate families, and in winter they unite in flocks, which makes it easier for them to feed or protect (wolves, many species of birds).

Adaptations to periodic environmental factors

These are adaptations to environmental factors that have a certain periodicity in their manifestation. This type includes daily alternations of periods of activity and rest, states of partial or complete anabiosis (shedding of leaves, winter or summer diapauses of animals, etc.), animal migrations caused by seasonal changes, etc.

Adaptations to extreme living conditions

Plants and animals living in deserts and polar regions also acquire a number of specific adaptations. In cacti, the leaves have been transformed into spines (reducing evaporation and protecting them from being eaten by animals), and the stem has turned into a photosynthetic organ and reservoir. Desert plants have long root systems that allow them to obtain water from great depth. Desert lizards can survive without water by eating insects and obtaining water by hydrolyzing their fats. In addition to thick fur, northern animals also have a large supply of subcutaneous fat, which reduces body cooling.

Relative nature of adaptations

All devices are appropriate only for certain conditions in which they were developed. If these conditions change, adaptations may lose their value or even cause harm to the organisms that have them. The white coloration of hares, which protects them well in the snow, becomes dangerous during winters with little snow or severe thaws.

Relative character adaptations are also well proven by paleontological data indicating extinction large groups animals and plants that have not survived the change in living conditions.

Morphological adaptations involve changes in the shape or structure of an organism. An example of such adaptation is hard shell, providing protection from predatory animals. Physiological adaptations are associated with chemical processes in the body. Thus, the smell of a flower can serve to attract insects and thereby contribute to pollination of the plant. Behavioral adaptation is associated with a certain aspect of an animal’s life. A typical example is a bear's winter sleep. Most adaptations are a combination of these types. For example, blood sucking in mosquitoes is achieved through a complex combination of adaptations such as the development of specialized parts oral apparatus, adapted to sucking, the formation of search behavior to find a prey animal, as well as the development salivary glands special secretions that prevent the clotting of sucked blood.

All plants and animals constantly adapt to their environment. To understand how this happens, it is necessary to consider not only the animal or plant as a whole, but also the genetic basis of adaptation.

Genetic basis.

In each species, the program for the development of traits is embedded in the genetic material. The material and the program encoded in it are passed on from one generation to the next, remaining relatively unchanged, so that representatives of a given species look and behave almost the same. However, in a population of organisms of any species there are always minor changes genetic material and, therefore, variation in the characteristics of individual individuals. It is from these diverse genetic variations that the process of adaptation selects those traits or favors the development of those traits that most increase the chances of survival and thereby the preservation of genetic material. Adaptation can thus be thought of as the process by which genetic material increases its chances of persistence in subsequent generations. From this point of view, each species represents successful way preservation of certain genetic material.

To pass on genetic material, an individual of any species must be able to feed, survive until the breeding season, leave offspring, and then spread them over as wide an area as possible.

Nutrition.

All plants and animals must obtain energy from the environment and various substances, primarily oxygen, water and inorganic compounds. Almost all plants use the energy of the Sun, transforming it through the process of photosynthesis. Animals get energy by eating plants or other animals.

Each type in a certain way adapted to provide itself with food. Hawks have sharp claws for capturing prey, and the location of the eyes in the front of the head allows them to assess the depth of space, which is necessary for hunting when flying. high speed. Other birds, such as herons, have developed long neck and legs. They obtain food by carefully wandering through shallow water and lying in wait for unwary aquatic animals. Darwin's finches, a group of closely related bird species from the Galapagos Islands, provide a classic example of highly specialized adaptation to in different ways nutrition. Thanks to certain adaptive morphological changes, primarily in the structure of the beak, some species became granivorous, others became insectivorous.

Turning to fish, predators such as sharks and barracudas have sharp teeth to catch prey. Others, such as small anchovies and herring, are caught fine particles food by filtration sea ​​water through comb-shaped gill rakers.

In mammals, an excellent example of adaptation to the type of nutrition is the structural features of teeth. The canines and molars of leopards and other felines are exceptionally sharp, which allows these animals to hold and tear the body of their prey. Deer, horses, antelope and other grazing animals have large molars with wide, ribbed surfaces adapted for chewing grass and other plant foods.

Various ways to receive nutrients can be observed not only in animals, but also in plants. Many of them, primarily legumes - peas, clover and others - have developed symbiotic, i.e. mutually beneficial relationship with bacteria: bacteria convert atmospheric nitrogen into a chemical form available to plants, and plants provide energy to bacteria. Carnivorous plants such as sarracenia and sundew obtain nitrogen from the bodies of insects captured by trapping leaves.

Protection.

The environment consists of living and nonliving components. The living environment of any species includes animals that feed on members of that species. Adaptations predatory species aimed at efficient food production; Prey species adapt to avoid becoming prey to predators.

Many potential prey species have protective or camouflage colors that hide them from predators. Thus, in some species of deer, the spotted skin of young individuals is invisible against the background of alternating spots of light and shadow, and white hares are difficult to distinguish against the background of snow cover. Long thin bodies Stick insects are also difficult to see because they resemble twigs or twigs from bushes and trees.

Deer, hares, kangaroos and many other animals have evolved long legs that allow them to escape from predators. Some animals, such as opossums and hog snakes, have even developed a unique behavior called death faking, which increases their chances of survival, since many predators do not eat carrion.

Some types of plants are covered with thorns or thorns that repel animals. Many plants have a disgusting taste to animals.

Environmental factors, in particular climate, often place living organisms in difficult conditions. For example, animals and plants often have to adapt to temperature extremes. Animals escape the cold by using insulating fur or feathers, migrating to areas with more warm climate or falling into hibernation. Most plants survive the cold by entering a state of dormancy, equivalent to hibernation in animals.

In hot weather, the animal cools itself by sweating or frequent breathing, which increases evaporation. Some animals, especially reptiles and amphibians, are able to enter summer hibernation, which is essentially similar to winter hibernation, but is caused by heat rather than cold. Others are simply looking for a cool place.

Plants can maintain their temperature to some extent by regulating the rate of evaporation, which has the same cooling effect as sweating in animals.

Reproduction.

A critical step in ensuring the continuity of life is reproduction, the process by which genetic material is passed on to the next generation. Reproduction has two important aspects: the meeting of opposite-sex individuals for exchange genetic material and raising offspring.

Among the adaptations that ensure the meeting of individuals of different sexes is sound communication. In some species, the sense of smell plays an important role in this sense. For example, cats are strongly attracted to the smell of a cat in heat. Many insects secrete the so-called. Attractants are chemical substances that attract individuals of the opposite sex. Flower scents are an effective plant adaptation to attract pollinating insects. Some flowers smell sweet and attract nectar-feeding bees; others smell disgusting, attracting flies that feed on carrion.

Vision is also very important for meeting individuals of different sexes. In birds mating behavior the male, his lush feathers and bright coloring attract the female and prepare her for copulation. Flower color in plants often indicates which animal is needed to pollinate that plant. For example, flowers pollinated by hummingbirds are colored red, which attracts these birds.

Many animals have developed ways to protect their offspring in initial period life. Most adaptations of this kind are behavioral and involve actions by one or both parents that increase the chances of survival of the young. Most birds build nests that are specific to each species. However, some species, such as the cowbird, lay eggs in the nests of other bird species and entrust the young to the parental care of the host species. Many birds and mammals, as well as some fish, have a period when one of the parents goes to big risk, taking on the function of protecting the offspring. Although this behavior sometimes threatens the death of the parent, it ensures the safety of the offspring and the preservation of genetic material.

A number of animal and plant species use a different reproductive strategy: they produce huge number descendants and leave them unprotected. In this case, the low chances of survival of an individual growing individual are balanced by the large number of offspring.

Settlement.

Most species have developed mechanisms to remove offspring from the places where they were born. This process, called dispersal, increases the likelihood that offspring will grow up in unoccupied territory.

Most animals simply avoid places where there is too much competition. However, evidence is accumulating that dispersal is driven by genetic mechanisms.

Many plants have adapted to dispersing seeds with the help of animals. Thus, the fruits of the cocklebur have hooks on the surface, with which they cling to the fur of passing animals. Other plants produce tasty, fleshy fruits, such as berries, that are eaten by animals; seeds pass through digestive tract and are “seeded” intact in another place. Plants also use wind to spread. For example, the wind carries the “propellers” of maple seeds, as well as cottonweed seeds, which have tufts of fine hairs. Steppe plants such as tumbleweeds, which acquire a spherical shape by the time the seeds ripen, are driven by the wind over long distances, dispersing seeds along the way.

Above are just some of the most vivid examples adaptations. However, almost every trait of any species is the result of adaptation. All these signs form a harmonious combination, which allows the body to successfully lead its own special way of life. Man in all his features, from brain structure to shape thumb on the leg, is the result of adaptation. Adaptive traits contributed to the survival and reproduction of his ancestors, who had the same traits. In general, the concept of adaptation has great value for all areas of biology.

Adaptations (devices)

Biology and genetics

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

Adaptations

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

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

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

Examples of adaptation

Type of adaptation	Characteristics of adaptation	Examples
Special shape and structure of the body	Streamlined body shape, gills, fins	Fish, pinnipeds
Protective coloration	It can be continuous or dismembering; is formed in organisms living openly, and makes them invisible against the background of the environment	Gray and white partridge; seasonal change in fur color of a hare
Warning coloring	Bright, noticeable against the background of the environment; develops in species that have means of defense	Poisonous amphibians that sting and poisonous insects, inedible and scalding plants
Mimicry	Less protected organisms of one species resemble protected poisonous ones of another species in color.	Some non-venomous snakes similar in color to poisonous ones
Disguise	The shape and color of the body makes the organism similar to objects in the environment	Butterfly caterpillars are similar in color and shape to the tree branches where they live
Functional devices	Warm-blooded, active metabolism	Allows you to live in different climatic conditions
Passive protection	Structures and features that determine a greater likelihood of preserving life	Turtle shells, mollusk shells, hedgehog needles, etc.
Instincts	Swarming in bees when the second queen appears, caring for offspring, searching for food
Habits	Behavior changes in moments of danger	The cobra puffs up its hood, the scorpion raises its tail

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