The relative nature of fitness as exemplified by cacti, chameleons, and turtles. Examples of adaptations Reasons for adaptability

Sections: Biology

Target: to form knowledge among students about the adaptability of organisms to the environment.

Tasks:

educational: the formation of knowledge about the various ways of adaptation of organisms to environment;

developing: the ability to work with a textbook, analyze, compare, highlight the main thing, think logically

educational: promoting aesthetic education, the formation of a scientific worldview.

Equipment: table “Fitness and its relative nature”, photographs, drawings, collections of plant and animal organisms, presentation.

During the classes

In the form of a frontal conversation, it is proposed to answer questions.

1. How to explain the adaptability of living things to their environment?

2. How did the variety of species existing in nature arise?

3. Why is there an increase in the organization of living beings in the course of evolution?

To the questions: what explanation of the fitness of organisms was widespread in the 18th century? How did Lamarck explain these phenomena? - students easily give answers, which the teacher summarizes the remark about the contradictions between scientific facts that reveal the perfection of the organic world, the explanations offered then.

Students in groups receive assignments and different objects for work:

Consider the fruits and seeds of birch, pine, dandelion, poppy, etc., and determine the nature of their adaptability to distribution.

Students write down the results of the work in the table.

Each group of students makes a report on the results of the work by demonstrating objects. Then, based on the findings from the groups, generalizations are made about the various adaptations in the same environment.

Much attention should be paid to explaining the occurrence of adaptations according to Darwin's doctrine of natural selection versus Lamarck's explanation.

It is necessary to ensure that students can correctly explain from the perspective of Darwin's teaching how this or that adaptation arose.

The description of education is read and parsed long legs and a long neck according to Lamarck and Darwin.

Students are then asked to explain the occurrence:

white coloration of polar animals;
hedgehog needles;
shells in molluscs;
aroma wild rose;
similarities of a moth caterpillar with a knot

When answering, students give explanations of the facts on the basis of Darwinian doctrine, comparisons with a possible interpretation of the same examples according to Lamarck reveal its ideological essence.

The main attention is paid to the elucidation of the reasons due to which Lamarck's theory turned out to be powerless to explain the origin of organic evolution, which was brilliantly done by Charles Darwin.

Adaptation, or adaptation, is the ability of an organism to survive and leave offspring in a given habitat.

Examples of fitness

Causes of occurrence	Types of devices	Examples of
1. Protection from enemies	Protective coloration(makes organisms less visible against the background of the environment)	Ptarmigan, white hare (changes color depending on the season), coloration of female open-nesting birds (black grouse, hazel grouse), green color of caterpillar larvae, coloration of moths, etc.
	Disguise(body shape and coloration merge with the surrounding objects)	The moth caterpillar resembles a twig in shape and color, the stick insect is very similar to the stick of dry reed, some insects completely repeat the shape and color of the leaves
	Mimicry - imitation of a less protected organism of one type of a more protected organism of another species (or an object of the environment)	Imitation of some flies with stinging webbed-winged flies (fly - hoverfly - bee)
	Warning coloring- bright color, warning about the toxicity of a living organism.	Bright color of ladybug, fly agaric, many poisonous frogs, etc.
	Threatening pose	The Frilled Lizard has a brightly colored hood that reveals when it encounters an enemy, spectacled snakes, some caterpillars (hawk moth)
Adaptation to environmental conditions	Streamlined body shape	Fish, marine mammals, birds.
	Flight attachments	Feathers and wings of birds, wings of insects.
Reproduction adaptations	Marital behavior	In many animals (crane dances, deer fights)
	Pollination devices	By wind, insects, self-pollination in plants
	Seed transfer attachments	By wind, animals, water

TO morphological adaptations include - protective coloration, disguise, mimicry, warning coloration.

TO ethological or behavioral include - threatening postures, food storage.

Physiological adaptation is a set of physiological reactions that underlie the adaptation of the body to changes in environmental conditions and are aimed at maintaining the relative constancy of its internal environment - homeostasis.

Chemical interactions (ants secrete enzymes that are used by family members to coordinate activities)

Conservation of water in a cactus

Caring for offspring is a chain of successive reflexes developed in the process of evolution, ensuring the preservation of the species.

The tilapia fish carries caviar and juveniles in its mouth! The fry calmly swim around their mother, swallow something, wait. But as soon as the slightest danger arises, the mother gives a signal, sharply moving her tail and trembling her fins in a special way, and ... the fry immediately rush to the shelter - the mother's mouth.

Some frog species carry eggs and larvae in special brood pouches.

In mammals - in the construction of dens, burrows and other shelters for future offspring, maintaining the cleanliness of the body of the young, this instinct, apparently, is characteristic of all mammals, without exception.

The origin of fitness and its relativity

Charles Darwin showed that adaptations arise as a result of the action of natural selection. The following examples provide evidence of the relativity of adaptations:

1) useful organs in some conditions become useless in others: the relatively long wings of swifts, adapted for rapid flight, create certain difficulties when taking off from the ground

2) protective devices from enemies are relative: poisonous snakes (for example, vipers) are eaten by hedgehogs

3) the manifestation of instincts may also be inappropriate: for example, a defensive reaction (releasing a jet of foul-smelling liquid) of a skunk directed against a walking car

4) the observed "overdevelopment" of some organs, which becomes a hindrance to the body: the growth of incisors in rodents when they switch to eating soft food.

Students must firmly grasp that Darwin's teaching on relative fitness as a result of natural selection completely refutes idealistic statements about the divine origin and the absolute nature of organic expediency (K. Linnaeus), as well as about the innate ability of the organism to change under the influence only in a direction useful to them (Lamarck).

Consolidation of knowledge

1. An example of patronizing coloration is:

a) the similarity of the shape and color of the body with the surrounding objects;

b) imitation of the less protected more protected;

c) alternation of light and dark stripes on the body of the tiger.

2. The bright color of ladybirds, many species of butterflies, some species of snakes and other animals with odorous or poisonous glands is called:

a) disguise;

b) demonstrating;

c) mimicry;

d) warning.

3. The variety of adaptations is explained by:

a) only by the influence of environmental conditions on the body;

b) the interaction of genotype and environmental conditions;

c) only by the features of the genotype.

4. An example of mimicry:

b) a bright red color in a ladybug;

c) similarity in the color of the abdomen of a hoverfly and a wasp.

5. An example of masking:

a) green color in the song grasshopper;

b) similarity in the color of the abdomen of the hoverfly and the wasp;

c) a bright red color in a ladybug;

d) similarity in color of caterpillar and moth moth with a knot.

6. Any fitness of organisms is relative, because:

a) life ends with death;

b) adaptation is advisable in certain conditions;

c) there is a struggle for existence;

d) adaptation may not lead to the formation of a new species.

Bibliography

Mamontov S.G. General biology: Textbook. for students of secondary specialized study. institutions - 5th ed., erased. - M .: Higher. shk., 2003.
General biology: textbook. for stud. Educated. institutions of environments. prof. education / V.M. Konstantinov, A.G. Rezanov, E.O. Fadeeva; ed. V.M. Konstantinov. -M .: Publishing Center "Academy", 2010.

6. The emergence of devices. Relative character of the fit.

Adaptation is the harmony of the organism with the environment (in a broad sense). Adaptation is a special morphophysiological property capable of ensuring the survival and reproduction of organisms in a concert environment (in the narrow sense). The adaptation group - the means of passive protection - are those who, by their mere presence, determine the greater probability of the survival of individuals in the struggle for existence. a) hard protective covers; b) the ability to roll up into a ball (centipede, armadillo); c) needles and thorns; d) stinging hairs in plants, stinging clumps in animals; e) adaptive coloration and structure (shape) of the body - protective coloration (seasonal coloration (partridge)); dismembering coloration (tiger); counter shade (fish); brightly colored individuals (warning coloration); mimicry - imitative coloring and behavior, disguise, resemblance to inedible objects; f) complex adaptations (arose through small hereditary deviations) insectivorousness in plants, symbiosis.

The fitness of orgs is a result of the action of the forces of evolution in the given conditions of existence. Any fitness helps org-moms to survive only in those conditions in which it was formed under the influence of the driving forces of evolution. Under these conditions, it is relative (on a bright day in winter, the ptarmigan gives itself out as a shadow in the snow. Snowy hare, invisible in the snow in the forest, visible against the background of dark trunks.). Org-moss have unnecessary organs and signs. All these many and other factors say that fitness is not absolute, but relative.

7. Microevolution. Speciation. Evolution results.

Microevolution - evolutionary processes occurring within a species and leading to new, intraspecific groups: populations and subspecies. Population is an elementary evolutionary structure. Subspecies - group of populations of a given species - morphophysiologically different from all other populations within the species. Mutation is an elementary, evolutionary material.

An elementary evolutionary phenomenon is a change in the gene pool of a population. A gene pool is a set of genotypes of all individuals in a population. Genotype is a collection of genes of an individual. The elementary evolutionary factor guiding the evolutionary process is natural selection.

The formation of new species in nature occurs under the influence of the driving forces of evolution. When the conditions of the entity change within the species, a process of divergence of signs of divergence occurs, which leads to the formation of new groupings, individuals within the species. Initial stages evolutionary process, occur within a species and lead to an ar-yu new intraspecific groupings - populations of subspecies (this process is called microevolution). Geographic speciation - associated with the expansion of the range of the original species or with its dismemberment into isolated parts - physical barriers (rivers, lakes, mountains, climate ...). Ecological speciation occurs when populations of one species remain within the same area, but their living conditions are different (their genetic composition changes).

Evolution results. Evolution has 3 closely related important consequences:

1) Gradual complication and increase in the organization of living beings.

2) The relative adaptability of organisms to environmental conditions.

3) Variety of species.

Type criteria: 1.Morphological criterion - the similarities of the external and internal structure... 2.Ecological criterion - plants have different growing places. 3. Geographic criterion - area. 4. Physiological criterion: the impossibility of crossing species is the main meaning. They are limited by their physiological capabilities. 5. Genetic to. - defines the whole essence of the species (set of chromosomes). He does not play a huge role, i.e. it does not seem to be distinguished.

8. Documents of the evolution of the organic world.

Macroevolution is an image process from species of new genera, from genera - new families, etc. It takes place at long intervals and is inaccessible to direct study. In macroevolution, the same processes operate - natural selection and associated extinction, the struggle for existence. Macroevol-I has a divergent character, just like microevolution.

Embryological documents.

Even Charles Darwin noted that there are interrelationships between the individual development of orgms and their evolutionary development. Then these connections were studied in detail by other scientists. The similarity of the embryos. The internal organization of the embryos of fish, rabbit, lizard and man is very similar: all first have a notochord, then a spine of cartilaginous vertebrae, a circulatory system with one circle of cut. In the course of subsequent development, the similarity between the embryos weakens. All of the above indicates the origin of all chordates from one trunk, which disintegrated in the course of evolution into many branches. Biogenetic law. German scientists have established the law of correlation of ontogenesis. According to him, each individual in ontogeny is a brief repetition of phylogeny (the history of the development of its own species). For example, tadpoles of tailless amphibians develop a tail - a repetition of the signs of their tailed ancestors.

Paleontological docks.

Paleontology studies the fossil remains of extinct organisms and reveals their similarities and differences with modern organisms. Using fossil remains, paleontologists will restore the appearance of extinct organisms, learn about the plant, as well as the animal world of the past. Paleontological nach-ki talk about the connections between the various systematic groups. In some words, they were able to establish the transitional forms, in others - phylogenetic series (the series of species, lastly replacing one another). Fossil transitional forms. A group of animal-toothed reptiles was found. They combine the features of reptiles and mammals. Such organisms are referred to as transitional forms. Animal-toothed reptiles are similar to mammals in the structure of the skull, limbs and vertebrae, as well as in the division of teeth into molars, incisors and canines. Archeopteryx is an animal the size of a dove had the features of a bird, but still retained the features of dying. The signs of birds were obvious: the similarity of the hind limbs to the tarsus, the presence of feathers. Signs of presm-hsya: abdominal ribs, caudal vertebrae and the presence of teeth. Ar-ks could hardly fly well, tk. he has a sternum without a keel, weak pectoral and wing muscles. Phylogenetic series. Paleontologists managed to restore the phylogenetic series of animals. An example is the evolution of the horse. Naib-her other ancestor was as tall as a fox, the limbs were four-fingered, etc. , moved in jumps. But then the living conditions changed for the worse and now he could only escape from enemies with a fast run. In the process of the struggle for existence, his legs lengthened and the number of fingers reaching out to the soil decreased, the call hardening, which led to a fast run, etc.

The system of plants and animals is a display of evolution.

The evolution of life on earth is carried out by micro- and macro-evolutionary processes in their unity. Now organisms are divided into groupings using systematic categories: type (division for plants), class, order (order for plants), family, genus, species. For extensive systematic groups, intermediate categories are added: for types, for classes, etc. The multiplicity of systematic categories is caused by the extraordinary diversity of species and the desire of scientists to give such a system, which would reflect the relationship between groups of organisms. Each higher systematic group, starting from the genus, unites groups of lower rank and having common ancestor... The genus unites species that originated from one ancestor and that turned out and turned out to be, as a result of the struggle for existence and natural selection, capable of existing and successfully multiplying in different geogr-x, and eq-x conditions. Evolution has 3 closely related most important consequences: 1. The gradual complication and increase in the organization of living beings. 2. The relative fitness of organisms in the external environment. 3. Variety of species.

Plant and animal species are remarkably adapted to the environmental conditions in which they live. A huge number of the most diverse structural features are known, providing a high level of adaptation of the species to the environment. The concept " fitness of the species " includes not only external signs, but also correspondence buildings internal organs the functions they perform, for example the long and complex digestive tract of animals that eat plant foods (ruminants). Correspondence of the physiological functions of the organism to the living conditions, their complexity and diversity are also included in the concept of fitness.

Adaptive features of the structure, body color and behavior of animals. In fact, the entire structural and functional organization of representatives of a particular species is adaptive to the conditions in which this group lives. The most demonstrative are the structure of the body and the color of the integument.

Body shape. In animals, the shape of the body is adaptive to the environment. The shape of the aquatic mammal, the dolphin, is well known. His movements are light and precise. Self-driving speed in water reaches 40 km / h. Cases are often described of dolphins accompanying fast sea vessels, for example, destroyers, moving at a speed of 65 km / h. This is explained by the fact that dolphins are attached to the bow of the ship and use the hydrodynamic force of the ship's waves. But this is not their natural speed. The density of water is 800 times that of air. How does a dolphin manage to overcome it? In addition to other structural features, the shape of the body contributes to the ideal adaptation of the dolphin to the habitat and lifestyle. The torpedo shape of the body avoids the formation of a swirl of water flows around the dolphin.

The streamlined body shape contributes to the rapid movement of animals in the air. Flight feathers and contour feathers covering the bird's body completely smooth out its shape. Birds are devoid of protruding auricles; in flight, they usually retract their legs. As a result, birds are much faster than all other animals in speed. For example, a peregrine falcon dives on its prey at a speed of up to 290 km / h. Birds move quickly even in water. A chinstrap penguin was observed swimming underwater at a speed of about 35 km / h.

In animals leading a secretive, lurking lifestyle, adaptations that make them resemble environmental objects are useful. The bizarre body shape of fish living in algae thickets helps them successfully hide from enemies. The similarity with objects of the habitat is widespread in insects. Beetles are known for their appearance resembling lichens, cicadas, similar to the thorns of those shrubs among which they live. Stick insects look like a small brown or green twig (Figure 19.5), and orthoptera mimics a leaf. Fish that lead a benthic life have a flat body.

Rice. 19.5.

Coloring of the integument of the body. A means of protection from enemies is and protective coloration. Protective is called the color of the integuments of the body, which ensures their owners success in the struggle for existence. Usually scientists distinguish between hiding or, conversely, warning coloration. Birds incubating eggs on the ground merge with the surrounding background. Their eggs, which have a pigmented shell, and the chicks hatching from them are also hardly noticeable (Fig. 19.6). The protective nature of egg pigmentation is confirmed by the fact that in species whose eggs are inaccessible to enemies - large predators, or in birds laying eggs on rocks or burying them in the ground, the protective color of the shell does not develop.

Rice. 19.6.

offspring on earth

Protective coloration is widespread among a wide variety of animals. Caterpillars of butterflies are often green, like the leaves, or dark, like the bark or earth. Bottom fish are usually colored like a sandy bottom (rays and flounders). At the same time, flounders are still able to change color depending on the color of the surrounding background. The ability to change color by redistributing pigment in the integument of the body is also known in terrestrial animals (chameleon). Desert animals are usually yellow-brown or sandy-yellow in color. Solid color patronizing it is characteristic of both insects (locusts) and small lizards, as well as large ungulates (antelopes) and predators (lions).

If the background of the environment does not remain constant depending on the season of the year, many animals change color. For example, inhabitants of middle and high latitudes (arctic fox, hare, ermine, ptarmigan) are white in winter, which makes them invisible in the snow.

Two-tone hiding color is often seen in aquatic animals. So, in most fish, for example, in herring, the back is highly pigmented, and the ventral side of the body is light. If you look at the fish from above, from a zone of greater illumination, then against the background of the deepening darkness, the dark back is practically invisible. On the contrary, when viewed from the depths - in the direction of greater illumination - the abdomen is imperceptible. This color is important for predators (dolphins, sharks, etc.) and for their prey.

Another variant of the concealing coloring is the dismembering coloring. It is characterized by the alternation of dark and light stripes and spots on the body, corresponding to the change of light and shadow in the habitat familiar to the species (Fig. 19.7). Such a coincidence makes the organism invisible due to the violation of the idea of its shape. For example, a tiger hunts in ambush on forest edges, where tufts of yellow grass alternate with dark soil. Zebra, feeding on the foliage of shrubs, in the savannah is almost invisible against the background of many-trunk. In addition, the dismembering coloration distorts the concept of body contours, which makes it even more effective.

Rice. 19.7.

However, animals often exhibit not hiding body coloration, but, on the contrary, attracting attention, unmasking. This color is characteristic of poisonous, scalding or stinging insects: bees, wasps, blister beetles. The birds never peck the ladybug, which is very noticeable, because of the poisonous secretion secreted by the insect. Inedible caterpillars and many poisonous snakes have a bright warning color. The bright color warns the predator in advance of the futility and danger of an attack. Through trial and error, predators quickly learn to avoid attacking prey with warning coloring.

The effectiveness of the warning coloration was the cause of a very interesting phenomenon - imitation, or mimicry(from the Greek. mimikos - imitative). Mimicry is called the resemblance of a defenseless or edible species to one or more unrelated species that are well protected and have a warning coloration. WITH ladybug in size, body shape and distribution of age spots, one of the species of cockroaches is very similar. Some edible butterflies mimic the body shape and color of poisonous butterflies, flies - wasps. The emergence of mimicry is associated with the accumulation, under the control of natural selection, of small successful mutations in edible species in the conditions of their cohabitation with inedible.

It is clear that the imitation of some species by others is justified: a much smaller part of individuals of both the species that served as the model and the imitating species are subject to extermination. However, it is necessary that the abundance of the mimic species be significantly less than the abundance of the model. Otherwise, mimicry is not useful: the predator will not develop a persistent conditioned reflex the shape or color to be avoided. How is the abundance of the mimic species kept low? It turned out that the gene pool of these species is saturated with lethal mutations. In a homozygous state, these mutations cause the death of insects, as a result of which a high percentage of individuals do not live to maturity.

In addition to protective - patronizing coloring, other means of protection are observed in animals and plants. Plants often have needles and thorns that protect them from being eaten by herbivores (cacti, wild rose, hawthorn, sea buckthorn, etc.). The same role is played by toxic substances that burn the hairs, for example, in nettles. Crystals of calcium oxalate, accumulating in the thorns of some plants, protect them from being eaten by caterpillars, snails and even rodents. Formations in the form of a hard chitinous cover in arthropods (beetles, crabs), shells in molluscs, scales in crocodiles, shells in armadillos and turtles protect them well from many enemies. The needles of the hedgehog and the porcupine also serve the same purpose. All these adaptations could appear only as a result of natural selection, i.e. preferential survival of better protected individuals.

Behavior. For the survival of organisms in the struggle for existence great importance has an adaptive behavior. The protective effect of a warning paint is enhanced when combined with appropriate behavior. For example, the bittern nests in the reeds. In moments of danger, she stretches her neck, lifts her head up and freezes. In this position, it is difficult to detect it even at close range. Many other animals that do not have active protection means, in case of danger, assume a resting pose and freeze (insects, fish, amphibians, birds). On the contrary, warning coloration in animals is combined with demonstrative behavior that frightens off a predator.

In addition to hiding or demonstrative, frightening behavior when an enemy approaches, there are many other options. adaptive behavior, ensuring the survival of adults or juveniles. This includes storing feed for an unfavorable season of the year. This is especially true for rodents. For example, the root vole, common in the taiga zone, collects cereal grains, dry grass, roots - up to 10 kg in total. Burrowing rodents (mole rats, etc.) accumulate up to 14 kg pieces of oak roots, acorns, potatoes, steppe peas. Great gerbil living in deserts Central Asia, at the beginning of summer, cuts the grass and drags it into holes or leaves it on the surface in the form of stacks. This food is used in the second half of summer, in autumn and winter. The river beaver collects stumps of trees, branches, etc., which it puts into the water near its dwelling. These warehouses can reach a volume of 20 m 3. Predatory animals also make feed supplies. The mink, some ferrets and canines store frogs, snakes, small animals, etc., killing them and burying them in certain places.

The time of greatest activity is also an example of adaptive behavior. In deserts, many animals go hunting at night when the heat subsides. The specialization of the activity of animals by the time of day led, for example, in birds, to the emergence of whole environmental groups species. So, "nocturnal predators" (owls, eagle owls, etc.) hunt at night, and "daytime" - a falcon, golden eagle, eagle - in the daylight.

Anchor points

The entire organization of any kind of living organisms is adaptable to the conditions in which it lives.
The adaptation of organisms to the environment is manifested at all levels of organization: biochemical, cytological, histological and anatomical.
Physiological adaptations are an example of the reflection of the structural features of an organization in given conditions of existence.

1. Give examples of the adaptability of organisms to living conditions.
2. Why is there a bright unmasking color in some species of animals?
3. What is the essence of the phenomenon of mimicry?
4. How is the low abundance of mimic species maintained?
5. Does the action of natural selection extend to the behavior of animals? Give examples.

Caring for offspring. Of particular importance are the devices that ensure the protection of offspring from enemies. Caring for offspring can manifest itself in different form... Many fish guard the eggs laid between the stones, actively driving away and biting the approaching potential enemies. The Azov and Caspian gobies lay eggs in holes dug in the muddy bottom, and then protect it during the entire development. The stickleback male builds a nest with entry and exit. Some American catfish stick eggs on their belly and carry them all the time they develop. Many fish hatch eggs in their mouths or even stomachs. At this time, the parent does not eat anything. The hatched fry stay close to the female (or male, depending on the species) for some time and, in case of danger, hide in the mother's mouth. There are species of frogs in which eggs develop in a special brood pouch on the back or in the voice sacs of the male.

The greatest safety of the offspring is achieved, obviously, when the embryos develop into mother's body(fig.19.8). Fertility in these cases (as in other forms of offspring care) decreases, but this is compensated by an increase in the survival rate of juveniles.

Rice. 19.8.

In arthropods and lower vertebrates, the resulting larvae lead an independent way of life and do not depend on their parents. But in some cases, parental care for offspring is manifested in the form providing them with food. The famous French naturalist J.A. Fabre was the first to describe this behavior in single wasps. Wasps attack beetles, spiders, crickets, praying mantises, caterpillars of various butterflies, immobilize them by immersing the sting exactly in the nerve nodes (Fig. 19.9), and lay eggs on them.

Rice. 19.9.A lone wasp drags a paralyzed grasshopper into its nest: the future larva is provided with food

The hatching wasp larvae are provided with food: they feed on the tissues of a living prey, grow and then pupate.

The described examples of caring for offspring in arthropods and lower vertebrates are found in a very small number of species. In most cases, fertilized eggs are left to fend for themselves. This explains the very high fertility of invertebrates and lower vertebrates. A large number of offspring under conditions of high extermination of juveniles serves as a means of struggle for the existence of the species as a whole.

Much more complex and diverse forms of care for offspring are observed in higher vertebrates. Complex instincts and the ability to individual training allow them to raise offspring with much greater success. So, birds lay fertilized eggs in special structures - nests, and not just into the environment, as all kinds of lower classes do. Eggs develop under the influence of heat supplied to them by the body of their parents, and do not depend on the randomness of the weather. Parents protect the nest from enemies in one way or another. Most bird species do not leave hatched chicks to fend for themselves, but for a long time they feed and protect. All this sharply increases the efficiency of reproduction in this group of animals.

The forms of behavior in mammals reach the highest degree of development. This also manifests itself in relation to the young. The animals not only feed their offspring, but also teach them how to catch prey. Even Darwin noted that predatory animals teach their young to avoid dangers, including hunters.

Thus, individuals with more advanced forms of offspring care survive in more and pass these traits further down the line from generation to generation.

Physiological adaptations. The appropriate shape and color of the body, purposeful behavior ensure success in the struggle for existence only when these signs are combined with the adaptation of vital processes to living conditions, i.e. physiological adaptations. Without such adaptations, it is impossible to maintain a stable metabolism in the body in constantly fluctuating environmental conditions. Let's look at some examples.

Ground amphibians a large number of water is lost through the skin. However, many of their species penetrate even deserts and semi-deserts. Survival of amphibians under conditions of a lack of moisture in these habitats is provided by a number of adaptations. The nature of their activity changes: it coincides with periods of high humidity. In the temperate zone, toads and frogs are active at night and after rains. In deserts, frogs hunt only at night, when moisture condenses on the soil and vegetation, and during the day they hide in rodent holes. In desert amphibian species that breed in temporary reservoirs, the larvae develop very quickly and undergo metamorphosis in a short time.

Various physiological adaptations to life in unfavorable conditions developed by birds and mammals. Many desert animals accumulate a lot of fat before the onset of the dry season: when it oxidizes, a large amount of water is formed. Birds and mammals are able to regulate water loss from the respiratory tract. For example, a camel, deprived of water, drastically reduces evaporation both from the respiratory tract and through the sweat glands.

A person's salt metabolism is poorly regulated, and therefore he cannot do without fresh water... But reptiles and birds that spend most of their life in the sea and drink sea water, acquired special glands that allow them to quickly get rid of excess salts.

The adaptations that develop in diving animals are very interesting. Many of them can do without oxygen for a relatively long time. For example, seals dive to a depth of 100-200 and even 600 m and stay under water for 40-60 minutes. What allows pinnipeds to dive for such a long time? This is primarily a large amount of a special pigment found in muscles - myoglobin. Myoglobin is able to bind oxygen 10 times more than hemoglobin. In addition, in water, a number of devices provide a much more economical consumption of oxygen than when breathing on the surface.

By natural selection, adaptations arise and are improved that facilitate the search for food or a mate for reproduction. The insects' chemical sense organs are amazingly sensitive. Male gypsy moths are attracted by the scent of the female's aromatic gland from a distance of 3 km. In some butterflies, the sensitivity of taste receptors is 1,000 times greater than the sensitivity of the receptors of the human tongue. Nocturnal predators such as owls have excellent low-light vision. Some snakes have a well-developed ability for thermal location. They distinguish objects at a distance if their temperature difference is only 0.2 ° C. Many animals are perfectly oriented in space using echolocation ( the bats, owls, dolphins).

The relative nature of the fitness of organisms. The structure of living organisms is very finely adapted to the conditions of existence. Any species trait or property that is adaptive in nature is appropriate in a given environment, in given living conditions. Thus, all the structural and behavioral features of a cat are appropriate for a predator waiting for prey in ambush: soft pads on the fingers and retractable claws, making the gait noiseless; huge pupil and high sensitivity of the retina, allowing you to see in the dark; fine hearing and movable ears, making it possible to accurately determine the location of the victim; the ability to wait for the appearance of prey for a long time and make a lightning jump; sharp teeth holding and tearing the victim. Likewise, the organization of insectivorous plants is adapted to catching and digesting insects and even small vertebrates (Figure 19.10).

Rice. 19.10.

Adaptations do not appear ready-made, but represent the result of a selection of random hereditary changes that increase the viability of organisms in specific conditions.

None of the adaptive features provide absolute security for their owners. Due to mimicry, most birds do not touch wasps and bees, however, there are species among them that eat wasps, bees, and their imitators. The hedgehog and the secretary bird eat snakes without harm. The shell of land turtles reliably protects them from enemies, but birds of prey lift them into the air and smash them on the ground.

Any adaptations are advisable only in the usual environment for the species. When environmental conditions change, they turn out to be useless or harmful to the body. The constant growth of rodent incisors is very important feature, but only when eating solid food. If the rat is kept on soft food, the incisors, without wearing out, grow to such a size that nutrition becomes impossible.

Thus, any structure and any function is an adaptation to the specific external environment for the species, or, as modern scientists say, “here and now”. Evolutionary changes - the formation of new populations and species, the emergence or disappearance of organs, the complication of organization - are due to the development of adaptations (adaptations). The expediency of living nature is the result of the historical development of species in certain conditions, therefore, it is always relative and has a temporary character.

Anchor points

Caring for offspring arises as a way to ensure the survival of the species against the background of a high degree of development nervous system and is one of the forms of physiological adaptations.
Any adaptations, including those caused by behavioral reactions, are relative and expedient only in specific conditions of existence.

Review questions and tasks

1. Why does the number of offspring decrease in species of animals that care for their offspring? Give examples.
2. What is the relative nature of the adaptive traits in organisms? Give examples of plants and animals.

The fitness of organisms (adaptation) is a complex characteristic features, allowing to survive in a certain environment and leave numerous strong continuation of the genus.

The driving forces of evolution influence the habituation to the emerging conditions. But conditions are never constant, they change, so all adaptations are relative.

The ptarmigan, merging with the snow, is revealed by a shadow. Organisms with new traits acting in a certain range may simply die, going beyond these boundaries. Only individuals who have adapted to new environment through natural selection.

Types of organisms adaptability

Morphological adaptations include:

Transformation of the body, namely: streamlining or flattening of the shape, webbing of the paws, thick hair.
With the help of disguise, you can become invisible against the background of the environment, become similar in color and shape to a leaf, stone, twig (insects, fish).
With a protective and dismembering coloration, you can merge with the environment in a changing situation (hare - hare, bird eggs, zebra).
The warning coloring is highlighted in bright color, specks, stripes, and is needed to scare away or warn of an attack (bees, snakes, ladybugs).
To warn and protect oneself, the weak, from the stronger, by becoming similar to him in color, body shape or behavior, is called mimicry (tropical snake, fly - babbling, cuckoo eggs).

Among the physiological adaptations are:

Preparing for life in changing conditions: - the camel accumulates fat; - the formation of glands that eliminate excess salt (marine reptiles and birds). - location of heat and sound; - falling into hibernation.
Behavior: - the smaller the number of cubs, the more care for them in order to preserve; - the formation of mating pairs during the reproduction of offspring and life in flocks with complicating conditions (birds, wolves). - scaring away (cobra, grin and growl of a dog, the smell of a skunk). - imitation of the wounded or the dead, hiding (possum, frog, bird). - prudence (winter sleep, storing food).
With the help of biochemical devices (special substance), the animal can defend itself or attack the enemy (poisons, antibiotic bacteria, special proteins and fats).

The nature of the fitness of organisms

Selection by nature leaves only the most adapted alive. But even the slightest change in the environment can render tools that have served well in the past useless or even harmful.

As a result, those organisms survive that have managed to adapt faster, and those who are late die out, giving the opportunity to form a new species. Such adaptations are formed for a very long time in a natural way and are relative, because living conditions change much faster than the necessary changes appear in animals.

Evidence for the relativity of adaptations:

methods of protection are not universal (dangerous for some poisonous snake eats a mongoose, hedgehog);
in some cases, instinct fails (a moth flies for nectar to a light flower, or may confuse it with fire);
an organ necessary in one environment is useless or harmful in other conditions (mountain geese with unnecessary membranes);
the fish is adapted to separate oxygen from water, on land it cannot do this; - green insects are not visible on the grass, on clean ground they will quickly be eaten.

The reasons for the adaptability of organisms

It has been established that individuals of the species will survive provided they change faster, adapting to the new requirements of the environment. The emergence of new characters and the emergence of a new species was called phyletic speciation.

Today, the diversity of species has significantly decreased compared to several thousand years ago. This is due to constant climate changes, ice ages, volcanic eruptions, earthquakes, environmental degradation, and the barbaric attitude of people. As a result, the most adapted organisms survive, and the main reason for adaptability belongs to natural selection.

The adaptability of organisms to the environment

To survive, you need to adapt to the conditions of life, and she will choose the best individuals and remove the weak. All animals live in different parts nature and their adaptive characteristics depend on it.

Laboratory work fitness of organisms

Laboratory work, with a problematic situation in the content, is necessary for the development of independent skills in studying and researching objects of biology. The existing problem gives rise to hypotheses, versions, proofs and teaches us to draw conclusions. Each job has a goal, questions, tasks and applications. And the progress of work is more convenient to display in a table.

Example. L. r. "Adaptation to the environment."

Target: to define the concept of the fitness of animals, to train the ability to identify adaptations.

Fly - a hoverfly can be found everywhere, except for the tundra and the desert. This is a short-mousled dipteran insect, similar to a wasp, but completely harmless. Hoverflies fly very quickly. Their connection with ants, bumblebees, leading a social lifestyle has been proven.

Adaptation of organisms to environmental factors

Any living organisms are affected by natural factors... TO inanimate nature include: temperature, change of day and night, seasons, soil features, landscape, chemical composition air and water, noise, radiation. Organisms adapt to this, but they cannot influence these conditions, which are called abiotic factors.

Adaptation to changes in nature by humans (anthropogenic factor) is of no small importance for the survival of animals. Being in natural communities, all living inhabitants of the planet are divided into groups with similar signs of adaptation to a particular environmental factor. These changes can be expressed both externally and internally, with a change in the nature of behavior.

For example, body temperature depends on the weather conditions in most representatives of the animal world. They are cold-blooded animals. They react by either decreasing or increasing the metabolic rate. When they slow down, they experience anabiosis, which contributes to the conservation of energy. In warm-blooded species, the temperature is always constant and does not affect metabolism. There are predators that hunt during the day, and there are those that only come out at night. Pets are active mainly during the day.

Examples of the fitness of organisms

The horse can run quickly with wide, comfortable hooves. Felines are able to sneak up silently, retracting their claws. The birds made their bodies easier to fly by getting rid of the bladder, one ovary, teeth and acquiring wings with different plumage.

Insects - caterpillars have adapted to become like a leaf of a plant, a twig. Crocodiles have special glands near their eyes that help remove excess salt. The camel stores fat in its humps, and when it breaks down, water is released. Polar bear retains warmth with a layer of subcutaneous fat and thick fur, wide paws allow you to walk on thin ice.

Study of the fitness of organisms

Initially, during the reign of religion, it was argued that all life on Earth was created by the existing wise God. That nature itself could not do it. The Creator created everyone so that they could do what is entrusted to them. K. Linnaeus also adhered to this theory.

JB Lamarck argued that all organisms are born with the ability to change, and throughout life they only have to improve these skills. Thus, new species appear with useful properties for themselves. But this theory does not explain the different colors of bird eggs and the benefits of the thorns for the hedgehog.

C. Darwin expressed his opinion; "... if an animal or plant can survive a sharp change in climate or other conditions, then its descendants will become the most common." A new trait that appears is passed on to the offspring if it contributes to survival.

Modern scientists, studying adaptation, have come to the conclusion that any useful variability occurs later than the right time. Some new signs even harm the animal in suddenly changed conditions.

Pronghorns rank second among all animals in running speed. But a special feature is the muscles that change the slope of the coat. This ability helps in hot or cold weather. And most importantly, seeing the danger, the observer fluffs up the hair of his rear, which immediately notices the whole herd.
The secret of toothfish, an Antarctic fish, is that with the help of a special protein that acts as antifreeze, its blood remains unfrozen even at minus 2 degrees.
Even a bear will envy the African protopter fish, which can sleep up to 4 years. She is a lungworm, having, along with the gills, also the pulmonary system.
Toad - a water-carrier sleeps in its shelter of slime, waiting for new rain, as many as seven.
The vulture bird is not only an orderly - it eats carrion, and it can also cool its body by urinating on the plumage.

conclusions

Each organism is best adapted to the conditions in which it has to live. This change only serves where it was purchased and is therefore considered relative. Natural selection leaves individuals only with those traits that have withstood the greatest deviation in the significance of a certain environmental factor.

Thanks to selection, organisms that are best adapted to the conditions around them survive, but the adaptations are always relative. Quite insignificant changes in the environment, as what was useful in previous conditions, loses its adaptive value.

Examples of relative accommodations

The Ussuri tiger has a protective coloration that hides it well in the thickets in summer, but in winter, after the snow falls, the coloration unmasks the predator. With the onset of autumn, the white hare sheds, but if the snow is delayed, then the whitened hare against the dark background of bare fields becomes clearly visible.

The characteristics of an organism, even in the conditions in which they were preserved by selection, never reach absolute perfection. So, the roundworm egg is well protected from the effects of poisons, but quickly dies from a lack of moisture and from high temperatures.

Poisonous glands are a reliable protection for many animals, but the poison of karakurt, deadly for camels and cattle, is safe for sheep and pigs. The viper is not a danger to the hedgehog.

The stalks of the euphorbia are not eaten by herbivorous mammals, but remain defenseless against the caterpillars of the euphorbia hawk, etc. Selection always has a wide field of activity for the further improvement of devices.

If conditions change, then the adaptations that were previously expedient cease to be. Then new adaptations appear, and the forms that were previously "expedient" die out.