An example of adaptation of people and animals in the surrounding world. Physiological adaptations: examples. Adaptations of organisms to living conditions What are morphological adaptations
Such an observation is interesting. In animals of the northern populations, all elongated parts of the body - limbs, tail, ears - are covered with a dense layer of wool and look relatively shorter than in representatives of the same species, but living in a hot climate.
This pattern, known as the Alain rule, applies to both wild and domestic animals.
There is a noticeable difference in the body structure of the northern fox and the fennec fox in the south, the northern wild boar and the wild boar in the Caucasus. Outbred domestic dogs in the Krasnodar Territory, cattle of local selection are distinguished by a lower live weight compared to representatives of these species, say, Arkhangelsk.
Often animals from the southern populations of long-legged and long-eared. Large ears, unacceptable at low temperatures, arose as an adaptation to life in a hot zone.
And the animals of the tropics have just huge ears (elephants, rabbits, ungulates). The ears of the African elephant are indicative, the area of \u200b\u200bwhich is 1/6 of the surface of the entire body of the animal. They have abundant innervation and vascularity. In hot weather, about 1/3 of the entire circulating blood passes through the circulatory system of the ear shells in an elephant. As a result of increased blood flow, excessive heat is given off to the external environment.
The desert hare Lapus alleni is even more impressive with its adaptive abilities to high temperatures. In this rodent, 25% of the entire body surface falls on bare auricles. It is not clear what the main biological task of such ears is: to detect the approach of danger in time or to participate in thermoregulation. Both the first and the second task are solved by the animal very effectively. The rodent has a keen ear. The developed circulatory system of the auricles with a unique vasomotor ability serves only thermoregulation. By increasing and limiting blood flow through the auricles, the animal changes heat transfer by 200-300%. Its hearing organs perform the function of maintaining thermal homeostasis and saving water.
Due to the saturation of the auricles with thermosensitive nerve endings and rapid vasomotor reactions, a large amount of excess thermal energy is transferred from the surface of the auricles to the external environment in both the elephant and especially the lepus.
The structure of the body of a relative of modern elephants, the mammoth, fits well into the context of the problem under discussion. This northern analogue of the elephant, judging by the preserved remains found in the tundra, was much larger than its southern relative. But the ears of the mammoth had a smaller relative area and, moreover, were covered with thick hair. The mammoth had relatively short limbs and a short trunk.
Long limbs are unfavorable at low temperatures, since too much thermal energy is lost from their surface. But in hot climates, long limbs are a useful adaptation. In desert conditions, camels, goats, horses of local selection, as well as sheep, cats, as a rule, have long legs.
According to H. Hensen, as a result of adaptation to low temperatures in animals, the properties of subcutaneous fat and bone marrow change. In arctic animals, bone fat from the phalanx of the fingers has a low melting point and does not freeze even in severe frosts. However, bone fat from bones that do not come into contact with a cold surface, such as the femur, has conventional physicochemical properties. Liquid fat in the bones of the lower extremities provides thermal insulation and joint mobility.
The accumulation of fat is noted not only in northern animals, for which it serves as a thermal insulation and a source of energy during a period when food is not available due to severe bad weather. Fat accumulate and animals living in hot climates. But the quality, quantity and distribution of body fat in northern and southern animals is different. In wild arctic animals, fat is distributed evenly throughout the body in the subcutaneous tissue. In this case, the animal forms a kind of heat-insulating capsule.
In animals of the temperate zone, fat as a heat insulator accumulates only in species with a poorly developed coat. In most cases, stored fat serves as a source of energy during the hungry winter (or summer) period.
In hot climates, subcutaneous fat deposits carry a different physiological burden. The distribution of body fat throughout the body of animals is characterized by great unevenness. Fat is localized in the upper and back parts of the body. For example, in African hoofed savannahs, the subcutaneous fat layer is localized along the spine. It protects the animal from the scorching sun. The belly is completely free of fat. It also makes a lot of sense. Ground, grass or water, which is colder than air, ensures efficient heat removal through the abdominal wall in the absence of fat. Small fat deposits and in animals in a hot climate are a source of energy for a period of drought and the associated hungry existence of herbivores.
The internal fat of animals in a hot and arid climate performs another extremely useful function. In conditions of lack or complete absence of water, internal fat serves as a source of water. Special studies show that the oxidation of 1000 g of fat is accompanied by the formation of 1100 g of water.
An example of unpretentiousness in the arid conditions of the desert are camels, fat-tailed and fat-tailed sheep, and zebu-like cattle. The mass of fat accumulated in the humps of a camel and the fat tail of a sheep is 20% of their live weight. Calculations show that a 50-kilogram fat-tailed sheep has a water supply of about 10 liters, and a camel even more - about 100 liters. The last examples illustrate the morphophysiological and biochemical adaptations of animals to extreme temperatures. Morphological adaptations extend to many organs. In northern animals, there is a large volume of the gastrointestinal tract and a large relative length of the intestine, they deposit more internal fat in the omentums and the perirenal capsule.
Animals of the arid zone have a number of morphological and functional features of the system of urination and excretion. As early as the beginning of the 20th century. morphologists have found differences in the structure of the kidneys of desert and temperate animals. In hot climate animals, the medulla is more developed due to an increase in the rectal tubular part of the nephron.
For example, in an African lion, the thickness of the renal medulla is 34 mm, while in a domestic pig it is only 6.5 mm. The ability of the kidneys to concentrate urine is positively correlated with the length of the loop of Hendle.
In addition to structural features in animals of the arid zone, functional features of the urinary system were found. So, for a kangaroo rat, the pronounced ability of the bladder to reabsorb water from the secondary urine is normal. In the ascending and descending channels of the loop of Hendle, urea is filtered - a process common to the nodule part of the nephron.
The adaptive functioning of the urinary system is based on neurohumoral regulation with a pronounced hormonal component. In kangaroo rats, the concentration of the hormone vasopressin is increased. So, in the urine of a kangaroo rat, the concentration of this hormone is 50 U / ml, in a laboratory rat - only 5-7 U / ml. In the pituitary tissue of a kangaroo rat, the content of vasopressin is 0.9 U/mg, in a laboratory rat it is three times less (0.3 U/mg). Under water deprivation, differences between animals persist, although the secretory activity of the neurohypophysis increases in both one and the other animal.
The loss of live weight during water deprivation in arid animals is lower. If a camel loses 2-3% of its live weight during a working day, receiving only low-quality hay, then a horse and a donkey under the same conditions will lose 6-8% of their live weight due to dehydration.
The temperature of the habitat has a significant impact on the structure of the skin of animals. In cold climates, the skin is thicker, the coat is thicker, and there are downs. All this helps to reduce the thermal conductivity of the body surface. In animals of a hot climate, the opposite is true: thin skin, sparse hair, low heat-insulating properties of the skin as a whole.
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Building BenefitsThese are the optimal proportions of the body, the location and density of the hair or feather cover, etc. The appearance of an aquatic mammal - a dolphin - is well known. His movements are light and precise. Independent speed in water reaches 40 kilometers per hour. The density of water is 800 times that of air. The torpedo-shaped shape of the body avoids the formation of eddies of water flows around the dolphin.
The streamlined shape of the body contributes to the rapid movement of animals in the air. Flight and contour feathers covering the bird's body completely smooth its shape. Birds are deprived of protruding auricles, in flight they usually retract their legs. As a result, birds are far superior to all other animals in terms of speed of movement. For example, the peregrine falcon dives on its prey at speeds up to 290 kilometers per hour.
In animals that lead a secretive, lurking lifestyle, adaptations are useful that give them a resemblance to environmental objects. The bizarre body shape of fish living in thickets of algae (rag-picker seahorse, clown fish, sea needle, etc.) helps them successfully hide from enemies. Resemblance to objects of the environment is widespread in insects. Beetles are known, their appearance resembling lichens, cicadas, similar to the thorns of those shrubs among which they live. Stick insects look like a small
a brown or green twig, and orthopterous insects imitate a leaf. A flat body has fish leading a benthic lifestyle (for example, flounder).
Protective coloration
Allows you to be invisible among the surrounding background. Thanks to the protective coloration, the organism becomes difficult to distinguish and, therefore, protected from predators. Bird eggs laid on sand or on the ground are gray and brown with spots, similar to the color of the surrounding soil. In cases where eggs are not available to predators, they are usually devoid of coloration. Butterfly caterpillars are often green, the color of the leaves, or dark, the color of the bark or earth. Bottom fish are usually painted to match the color of the sandy bottom (stingrays and flounders). At the same time, flounders also have the ability to change color depending on the color of the surrounding background. The ability to change color by redistributing the pigment in the integument of the body is also known in terrestrial animals (chameleon). Desert animals, as a rule, have a yellow-brown or sandy-yellow color. Monochromatic protective coloration is characteristic of both insects (locusts) and small lizards, as well as large ungulates (antelopes) and predators (lion).
Warning coloration
Warns a potential enemy about the presence of protective mechanisms (the presence of poisonous substances or special protection organs). Warning coloring distinguishes from the environment with bright spots or stripes of poisonous, stinging animals and insects (snakes, wasps, bumblebees).
Mimicry
The imitative resemblance of some animals, mainly insects, to other species, providing protection from enemies. It is difficult to draw a clear line between it and the patronizing color or form. In the narrowest sense, mimicry is the imitation by a species, defenseless against some predators, of the appearance of a species avoided by these potential enemies due to inedibility or the presence of special means of protection.Mimicry is the result of homologous (same) mutations in different species that help unprotected animals survive. For mimic species, it is important that their numbers be small compared to the model they imitate, otherwise the enemies will not develop a stable negative reflex to warning coloration. The low number of mimic species is supported by a high concentration of lethal genes in the gene pool. In the homozygous state, these genes cause lethal mutations, as a result of which a high percentage of individuals do not survive to adulthood.
In the process of evolution, as a result of natural selection and the struggle for existence, adaptations (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 aspects of the life processes of organisms and therefore can be of several types.
Morphological adaptations
They are associated with a change in the structure of the body. For example, the appearance of membranes between the toes in waterfowl (amphibians, birds, etc.), a thick coat in northern mammals, long legs and a long neck in marsh birds, a flexible body in burrowing predators (for example, in weasels), etc. In warm-blooded animals, when moving north, an increase in the average body size (Bergmann's rule) is noted, which reduces the relative surface and heat transfer. In bottom fish, a flat body is formed (stingrays, flounder, etc.). Plants in northern latitudes and high mountain regions often have creeping and cushion-shaped forms, 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 of protection against predators. Thanks to her, animals become less visible on the ground. 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. Bottom fish, most insects and many other animal species have a protective coloration. In the north, white or light coloration is more common, helping to camouflage in the snow (polar bears, polar owls, arctic foxes, pinniped cubs - white pups, etc.). A number of animals developed 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, spotted deer, etc.). Some animals are able to change color very quickly depending on the conditions (chameleons, octopuses, flounder, etc.).
Disguise
The essence of disguise is that the shape of the body and its color make animals look like leaves, knots, branches, bark or thorns of plants. Often found in insects that live on plants.
Warning or threatening coloration
Some types of insects that have poisonous or odorous glands have a bright warning color. Therefore, predators that once encountered them remember this color 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 mimics their venomous counterparts. For example, some non-venomous 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 the 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 a change in behavior in certain conditions. For example, caring for offspring leads to better survival of young animals and increases the resilience of their populations. During the mating season, many animals form separate families, and in winter they unite in flocks, which facilitates their food or protection (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 (dropping leaves, winter or summer diapauses of animals, etc.), animal migrations caused by seasonal changes, etc.
Adaptations to extreme living conditions
Plants and animals that live in deserts and polar regions also acquire a number of specific adaptations. In cacti, the leaves have evolved into spines (to reduce evaporation and protect against being eaten by animals), and the stem has evolved into a photosynthetic organ and reservoir. Desert plants have a long root system that allows them to extract water from great depths. Desert lizards can survive without water by eating insects and obtaining water by hydrolyzing their fats. In northern animals, in addition to thick fur, there is also a large supply of subcutaneous fat, which reduces body cooling.
Relative nature of adaptations
All adaptations are expedient only for certain conditions in which they have developed. When these conditions change, adaptations can lose their value or even harm the organisms that have them. The white color of hares, which protects them well in the snow, becomes dangerous during winters with little snow or strong thaws.
The relative nature of adaptations is also well proven by paleontological data, which testify to the extinction of large groups of animals and plants that did not survive the change in living conditions.
Adaptations (devices)
Biology and genetics
The relative nature of adaptation: according to a specific habitat, adaptations lose their significance when it changes; hare hare is noticeable against the background of arable land and trees during a delay in winter or during a thaw in early spring; 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 coloration Sometimes continuous and dissecting; is formed in organisms living openly and makes them invisible ...
Adaptations (devices)
Adaptation (or adaptation) is a complex of morphological, physiological, behavioral and other features 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 factors of evolution.
The relative nature of adaptation: corresponding to a specific habitat, adaptations lose their significance when it changes (the white hare during a delay in winter or during a thaw, in early spring it is noticeable against the background of arable land and trees; aquatic plants die when water bodies dry up, etc.).
Adaptation examples
|
Type of adaptation |
Adaptation characteristic |
Examples |
|
The special shape and structure of the body |
Streamlined body shape, gills, fins |
Fish, pinnipeds |
|
Protective coloration |
It happens continuous and dismembering; is formed in organisms living openly, and makes them invisible against the background of the environment |
Gray and white partridges; seasonal change in the color of the fur of a hare |
|
Warning coloration |
Bright, noticeable against the background of the environment; develops in species with protective means |
Poisonous amphibians, stinging and poisonous insects, inedible and burning plants |
|
Mimicry |
Less protected organisms of one species are similar in color to protected poisonous ones of another species. |
Some non-venomous snakes are similar in coloration to venomous ones. |
|
Disguise |
The shape and color of the body makes the body look like objects of the environment. |
Butterfly caterpillars are similar in color and shape to the knots of the trees where they live. |
|
Functional fixtures |
Warm-blooded, active metabolism |
Allow to live in different climatic conditions |
|
Passive Defense |
Structures and features that determine the greater likelihood of life saving |
Turtle shells, mollusk shells, hedgehog quills, etc. |
|
instincts |
Swarming in bees when a second queen appears, caring for offspring, searching for food |
|
|
habits |
Behavior changes in moments of danger |
The cobra puffs out its hood, the scorpion lifts its tail |
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The textbook complies with the Federal State Educational Standard for Secondary (Complete) General Education, is recommended by the Ministry of Education and Science of the Russian Federation and is included in the Federal List of Textbooks.
The textbook is addressed to students in grade 11 and is designed to teach the subject 1 or 2 hours per 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 of the driving forces of evolution, organisms develop and improve adaptations to environmental conditions. Fixation in isolated populations of various adaptations can eventually lead to the formation of new species.
Review questions and assignments
1. Give examples of the adaptability of organisms to the conditions of existence.
2. Why do some animals have a bright, unmasking color, while others, on the contrary, are patronizing?
3. What is the essence of mimicry?
4. Does the action of natural selection extend to the behavior of animals? Give examples.
5. What are the biological mechanisms for the emergence of adaptive (concealing 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! Execute!
1. Why is there no absolute adaptation to living conditions? Give examples proving the relative nature of any device.
2. Boar cubs have a characteristic striped coloration that 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, for which animals and why is it typical?
3. Gather information about warning color animals 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 in front of elementary school students.
Work with computer
Refer to the electronic application. Study the material and complete the assignments.
Repeat and remember!
Man
Behavioral adaptations are innate unconditioned 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 proposed to divide all unconditioned reflexes into three groups, differing in the characteristics of the interaction of individuals with each other and with the environment. Vital reflexes(from lat. vita - life) are aimed at preserving the life of the individual. Failure to comply with them leads to the death of the individual, and the implementation does not require the participation of another individual of the same species. This group includes food and drink reflexes, homeostatic reflexes (maintaining a constant body temperature, optimal breathing rate, heart rate, etc.), defensive ones, which, in turn, are divided into passive-defensive (runaway, hiding) and active defensive (attack on a threatening object) and some others.
To zoosocial, or role-playing reflexes include those variants of innate behavior that arise when interacting with other individuals of their species. These are sexual, parent-child, territorial, hierarchical reflexes.
The third group is reflexes of self-development. They are not connected with adaptation to a specific situation, but, as it were, turned to the future. Among them are exploratory, imitative and playful behavior.
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