Living organisms, habitat. Adaptation of organisms to their environment. Types of living organisms. The adaptability of organisms is the result of the action of evolutionary factors. Relative nature of adaptations What is the adaptation of an organism called?

The emergence of adaptation of organisms.
The main reason for the appearance of various adaptations of living organisms to their environment is selection. For example, it is known that the partridge is a forest bird. Depending on its habitat, it has various adaptations: a) shortening of the beak in connection with obtaining food from under the snow and leaf litter: b) the appearance of horny folds at the ends of the fingers to facilitate movement on thick snow cover; c) expansion, rounding of the wings for rapid lifting into the air (the ancestors of the partridge did not have such a structure).
To further spread, the fruits and seeds of plants also underwent various changes. These are hooks, spines with which they are attached to animals, or light fluff that is scattered by the wind.
The appearance of fitness in plants and animals is a characteristic phenomenon, but in any case, fitness does not appear immediately. As a result of a long evolutionary process, individuals appear with special characteristics adapted to the conditions external environment.
Features of adaptation in structure, color, body shape and behavior are clearly visible in the example of an aquatic mammal - the dolphin. The pointed shape of the body allows it to move easily and freely in the water in different directions. The dolphin's speed reaches 40 km/h. And in birds, indicators of fitness for flight are the presence of feathers covering the body; absence of ears and teeth; the ability to turn the head 180"; lightness of bones; rapid digestion of food in the stomach, etc.
In many animals, their adaptation is so developed that it is difficult to distinguish them from environment. The body shape, coloring of fish and animals living in dense thickets of algae help them successfully hide from enemies.

Types of adaptability:

Protective (camouflage) coloring and its types.
Instinctive adaptation.
Caring for offspring.
Physiological adaptation.

Rice. 21. Adaptation of moths by changing color to the corresponding colors of the tree trunk: 1 - equal number of marked dark and light butterflies; 2 - light tree trunk; 3 - increase in the number of light butterflies; 4 - increase in the number of dark butterflies; 5 - dark tree trunk

1. Protective (camouflage) coloring and its types. Protective coloration is the adaptability of organisms that live openly and may be accessible to enemies. Birds that incubate eggs on the ground (grouse, partridge, quail, etc.) blend into the surrounding background. A bird sitting motionless on a nest is almost invisible to its enemies. The eggs, which have a pigmented shell, and the chicks hatching from them are also hardly noticeable. In large predators whose eggs are inaccessible to enemies, or in birds that lay eggs high on rocks or bury them. into the ground, the protective color of the shell does not develop. Butterfly caterpillars are usually green, the color of the leaves, or dark, the color of the bark. Bottom-dwelling fish (skate, flounder) are often colored to match the color of sand.
Desert animals are usually sandy-yellow in color. A monochromatic protective color is characteristic of insects (locusts), lizards, saigas, and lions. Depending on the time of year, many animals change color. For example, the Arctic fox, white hare, and partridge are white in winter. Daytime butterflies have protective coloring on the lower part of their wings, while night butterflies have a protective color on the upper part of their wings, so during the day they become noticeable to enemies and may die (the lower part of their wings is light). The protective coloring can also be observed in the shape of insects: the pupa of butterflies on a branch is very similar to a bud; a larva attached to a branch in a motionless state, similar to a tree branch, etc.
Protective coloring is especially useful in the initial stages individual development organism (eggs, larva, chick). Protective coloring is necessary for animals that move slowly or have entered a state of rest.
Many animals are able to quickly change color depending on the color of their environment, and this ability is inherited. For example: chameleon, flounder, agama.

Types of protective coloring:

protective painting;
attractive coloring;
threatening coloring;
imitative coloring.

1. Protective warning paint characteristic of poisonous, stinging or burning insects. For example, birds never peck a ladybug (red, yellow, brown, dark red, striped) because of the toxic, bitter yellowish liquid it secretes (Fig. 22). If the chicks accidentally peck this beetle, then next time they do not approach it. The carrion beetle secretes an unpleasant, burning liquid and is bright red striped in color. The coloring of bees, bumblebees, wasps, and poisonous snakes protects them from predators. Protective coloring also depends on the behavior of some insects and animals. Sometimes crawling beetles freeze in moments of danger. A bittern nesting in the reeds, accidentally seeing an enemy, stretches its neck, raises its head up and freezes. Warning coloration in animals is combined with behavior that scares away predators.

Rice. 22. Warning coloring: 1 - ladybug; 2 - blister

2. Attractive coloring. This coloration is especially important during breeding. The bright colors of red butterflies, blue-winged grasshoppers, jerboas, and the plumage of male birds attract females during the breeding season. On ordinary days, the color blends into the environment and becomes invisible to enemies (Fig. 23).

Rice. 23. Attractive coloring: 1 - red sash; 2 - blue-winged filly; 3 - jerboa

3. Menacing coloring. When in danger, animals take a threatening pose. For example, in moments of danger, a cobra raises its head straight, inflates its neck and takes a threatening pose; The darkling beetle raises its abdomen and emits an unpleasant odor. The long-eared roundhead instantly opens the folds of skin on its head and freezes with its mouth open. On the open wings of the praying mantis there are spots similar to eyes. In case of danger, by opening its wings, the praying mantis scares away its enemy. Moths have the same spots (Fig. 24).

Rice. 24. Menacing coloring: ocular spots on the wings of a butterfly (1) in a threat pose look like the eyes of an elf owl (2)

4. Imitating coloring -mimicry(Greek mimikos - “imitation”). This is the imitation of animals and plants by living organisms or certain inanimate objects of the environment. The warning coloration of unprotected organisms resembles one or more species. For example, in body shape, size, and bright color, a cockroach is similar to a ladybug. The body shape of the seahorse and fish resembles algae. White butterfly with an unpleasant odor and bright color it imitates inedible butterflies from the heliconid family (Fig. 25), and flies imitate wasps. The similarity of non-venomous snakes with poisonous ones helps them protect themselves from enemies and survive.

Rice. 25. Imitative coloration: the white butterfly (T) is similar to the poisonous heliconid butterfly (2)

Examples of imitative plant coloring.
Imitative coloration in plants is necessary to attract or intimidate animals. Usually there is no nectar on the belozor flower. To attract insects, it is similar to a honey plant. Insects, landing on a flower, contribute to its pollination. Flowers of an insectivorous plant (Nepenthes) have bright color. Insects, landing on a flower, instantly fall into a “trap” and die. An orchid resembles the female of some insects in its flower shape and smell, so male insects involuntarily land on the flower and pollinate it.
Mimicry arises “under the control” of natural selection. Its occurrence is associated with the accumulation of small beneficial mutations in edible species in conditions of their cohabitation with inedible ones. One of the main weapons of defense against enemies and adaptive characteristics is: in beetles and crabs - chitinous cover, in mollusks - shells, in crocodiles - scales, in armadillos and turtles - carapace, in hedgehogs and porcupines - quills.

Fitness. Protective coloration. Protective painting. Attractive coloring. Menacing coloring. Imitative coloring (mimicry).

main reason various adaptations of organisms to environmental conditions is selection.
Protective coloration is an adaptation necessary to protect organisms leading an open lifestyle from enemies.
Protective coloration is a type of protective coloration characteristic of poisonous, stinging, burning insects.
Attractive coloration is a type of protective coloration during the reproduction period of organisms.
Menacing coloring is a way of protecting animals from enemies by adopting a threatening pose.
Imitation of living organisms and inanimate objects of the environment is an adaptation of organisms that are unable to defend themselves or are inactive.
What traits of organisms determine fitness?
How does fitness occur?
Name the types of protective coloring.
Give an example of protective paint.

What organisms are characterized by imitative coloration?
Give examples that prove the usefulness of attractive colors.
What are examples of mimic coloration in plants?

Exercise
Have you ever encountered insects in nature that freeze when touched? Pay attention to their actions, immobility. Pay attention to insects that produce an unpleasant odorous odor. Compare them. This activity will help you become more familiar with the protective and threatening colors of animals.
Try to complete the task.
What type of protective coloration are these examples? Enter accordingly in capital letters: "ZShch" - protective; "PR" - attractive; "PD" is imitative.

Ladybug. 5. Nepenthes (insectivorous plant).
Butterfly. 6. Bittern.
Darkling beetle. 7. Male pheasant.
Sea Horse. 8. Praying Mantis.

Sections: Biology

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

Tasks:

educational: the formation of knowledge about the various ways in which organisms adapt to the environment;

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

educational: promoting aesthetic education, forming a scientific worldview.

Equipment: table “Adaptability 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 beings to their environment?

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

3. Why does the organization of living beings increase during evolution?

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

Students in groups receive assignments and different objects to work on:

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

Students record the results of their work in a table.

Each group of students makes a report on the results of their work, showing objects. Generalizations are then made about the variety of adaptations in the same environment based on the findings from the groups.

Much attention should be paid to the explanation of the emergence of adaptations according to Darwin's doctrine of natural selection in comparison with Lamarck's explanation.

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

The description of the formation of long legs and a long neck according to Lamarck and Darwin is read and analyzed.

Students are then asked to explain the occurrence:

white coloration of polar animals;
hedgehog quills;
shells of mollusks;
wild rose aroma;
similarities between the moth caterpillar and a twig

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

The main attention is paid to elucidating the reasons why Lamarck's theory was 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 environment.

Examples of fitness

Causes	Types of devices	Examples
1. Protection from enemies	Protective coloration(makes organisms less noticeable against the background of the environment)	Ptarmigan, hare (changes color depending on the time of year), coloring of female open-nesting birds (grouse, hazel grouse), green color caterpillar larvae, coloring of moths, etc.
	Disguise(body shape and color merge with 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 species by a more protected organism of another species (or an environmental object)	Imitation of some flies by stinging hymenoptera (fly - hoverfly - bee)
	Warning coloring- bright coloring, warning of the toxicity of a living organism.	Bright coloring of ladybug, fly agaric, many poisonous frogs and so on.
	Threatening poses	The frilled lizard has a brightly colored hood, which opens when meeting an enemy, spectacled snakes, some caterpillars (hawkmoth)
Adaptations to environmental conditions	Streamlined body shape	Fish, marine mammals, birds.
	Adaptations for flight	Feathers and wings of birds, wings of insects.
Adaptations for reproduction	Mating behavior	Many animals (crane dances, deer fights)
	Adaptations for pollination	By wind, insects, self-pollination in plants
	Adaptations for seed transfer	Wind, animals, water

TO morphological adaptations include: protective coloring, camouflage, mimicry, warning coloring.

TO ethological or behavioral include threatening postures, stockpiling food.

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

Chemical interaction (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 sequential reflexes developed during the process of evolution, ensuring the preservation of the species.

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

Some species of frogs carry eggs and larvae in special brood pouches.

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

The origin of adaptations and their relativity

C. Darwin showed that adaptations arise as a result of the action of natural selection. The following examples can serve as proof 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 against 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 stream of foul-smelling liquid) of a skunk directed against a moving car

4) the observed “overdevelopment” of some organs, which becomes a hindrance for the body: the growth of incisors in rodents when switching to eating soft food.

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

Consolidation of knowledge

1. An example of a protective coloring is:

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

b) imitation of the less protected by the more protected;

c) alternating light and dark stripes on the tiger’s body.

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

a) camouflage;

b) demonstrating;

c) mimicry;

d) warning.

3. The variety of devices is explained by:

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

b) interaction of genotype and environmental conditions;

c) only by the characteristics of the genotype.

4. Example of mimicry:

b) bright red color of the ladybug;

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

5. Masking example:

a) green coloration of the singing grasshopper;

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

c) bright red color of the ladybug;

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

6. Any fitness of organisms is relative, because:

a) life ends in death;

b) adaptation is appropriate 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 specialization. textbook institutions – 5th ed., erased. – M.: Higher. school, 2003.
General biology: textbook. for students Educated institutions prof. education / V.M. Konstantinov, A.G. Rezanov, E.O. Fadeeva; edited by V.M. Konstantinov. -M.: Publishing Center “Academy”, 2010.

The environment includes:

natural - appeared on Earth regardless of human activity;
technogenic - created by people;
external is everything that is around the body and also affects its functioning.

How do living organisms change their environment? They contribute to changes in the gas composition of the air (as a result of photosynthesis) and take part in the formation of relief, soil, and climate. Thanks to the influence of living beings:

oxygen content increased;
the amount of carbon dioxide has decreased;
the composition of the waters of the World Ocean has changed;
rocks of organic content appeared.

Thus, the relationship between living organisms and their habitat is a strong circumstance that provokes various transformations. There are four distinct living environments.

Ground-air habitat

It includes air and ground parts and is excellent for the reproduction and development of living beings. This is a rather complex and diverse environment, which is characterized by a high degree of organization of all living things. Soil exposure to erosion and pollution leads to a decrease in the number of living beings. In the terrestrial world, organisms have a fairly well developed external and internal skeleton. This happened because the density of the atmosphere is much less than the density of water. Quality and structure are considered one of the most important conditions for existence. air masses. They are in continuous motion, so the air temperature can change quite quickly. Living things that live in this environment must adapt to its conditions, so they have developed an adaptation to sudden temperature fluctuations.

The air-terrestrial habitat is more diverse than the aquatic one. Pressure drops are not so pronounced here, but a lack of moisture occurs quite often. For this reason, terrestrial living creatures have mechanisms that help them with the supply of water to the body, mainly in arid areas. Plants develop a strong root system and a special waterproof layer on the surface of the stems and leaves. Animals have an exceptional structure of external integument. Their lifestyle helps maintain water balance. An example would be migration to watering holes. The composition of the air also plays an important role for terrestrial living beings, providing the chemical structure of life. The raw material source for photosynthesis is carbon dioxide. Nitrogen is required to connect nucleic acids and proteins.

Adaptation to the environment

The adaptation of organisms to their environment depends on their place of residence. Flying species have developed a certain body shape, namely:

light limbs;
lightweight design;
streamlining;
presence of wings for flight.

In climbing animals:

long grasping limbs, as well as a tail;
thin long body;
strong muscles that allow you to pull up your torso and throw it from branch to branch;
sharp talons;
powerful grasping fingers.

Running living creatures have the following features:

strong limbs with low mass;
reduced number of protective horny hooves on the toes;
strong hind legs and short forelimbs.

In some species of organisms, special adaptations allow them to combine the characteristics of flight and climbing. For example, having climbed a tree, they are capable of long jumps and flights. Other types of living organisms can run fast and also fly.

Aquatic habitat

Initially, the life activity of creatures was associated with water. Its features include salinity, flow, food, oxygen, pressure, light and contribute to the systematization of organisms. Pollution of water bodies has a very bad effect on living creatures. For example, due to a decrease in water level in the Aral Sea, most of the flora and fauna, especially fish, have disappeared. A huge variety of living organisms live in the expanses of water. From water they extract everything they need for life, namely food, water and gases. For this reason, the entire diversity of aquatic living creatures must adapt to the basic features of existence, which are formed by chemical and physical properties water. The salt composition of the environment is also of great importance for aquatic inhabitants.

A huge number of representatives of flora and fauna, which spend their lives in suspension, are regularly found in the thickness of the water body. The ability to soar is ensured by the physical properties of water, that is, the force of buoyancy, as well as by the special mechanisms of the creatures themselves. For example, multiple appendages, which significantly increase the surface of the body of a living organism compared to its mass, increase friction with water. The next example of inhabitants of an aquatic habitat is jellyfish. Their ability to stay in a thick layer of water is determined by the unusual shape of the body, which looks like a parachute. In addition, the density of water is very similar to the density of the body of a jellyfish.

Living organisms whose habitat is water, different ways adjusted to the movement. For example, fish and dolphins have a streamlined body shape and fins. They are able to move quickly thanks to the unusual structure of the outer integument, as well as the presence of special mucus, which reduces friction with water. In certain species of beetles that live in an aquatic environment, the exhaust air released from the respiratory tract is retained between the elytra and the body, thanks to which they are able to rapidly rise to the surface, where the air is released into the atmosphere. Most protozoa move using cilia that vibrate, for example, ciliates or euglena.

Adaptations for the life of aquatic organisms

Different habitats for animals allow them to adapt and exist comfortably. The body of organisms is able to reduce friction with water due to the characteristics of the cover:

hard, smooth surface;
the presence of a soft layer present on the outer surface of the hard body;
slime.

Limbs represented:

flippers;
membranes for swimming;
fins.

The shape of the body is streamlined and has a variety of variations:

flattened in the dorso-abdominal region;
round in cross section;
laterally flattened;
torpedo-shaped;
teardrop-shaped.

In an aquatic habitat, living organisms need to breathe, so they developed:

gills;
air intakes;
breathing tubes;
bubbles that replace the lung.

Features of habitat in reservoirs

Water is able to accumulate and retain heat, so this explains the absence of strong temperature fluctuations, which are quite common on land. The most significant property of water is the ability to dissolve other substances in itself, which are subsequently used both for respiration and for nutrition by organisms living in it. water element. In order to breathe, oxygen is necessary, so its concentration in water is of great importance. The water temperature in the polar seas is close to freezing, but its stability has allowed the formation of certain adaptations that ensure life even in such harsh conditions.

This environment is home to a huge variety of living organisms. Fish, amphibians, large mammals, insects, mollusks, and worms live here. The higher the temperature of the water, the less diluted oxygen it contains, which dissolves better in fresh water than in sea water. Therefore, few organisms live in tropical waters, while polar waters contain a huge variety of plankton, which is used as food by fauna, including large cetaceans and fish.

Breathing is carried out over the entire surface of the body or through special organs - gills. For successful breathing, regular renewal of water is required, which is achieved by various vibrations, primarily by the movement of the living organism itself or its adaptations, such as cilia or tentacles. Great importance The salt composition of water also supports life. For example, mollusks and crustaceans require calcium to build their shells or shells.

Soil environment

It is located in the upper fertile layer of the earth's crust. This is a rather complex and very important component of the biosphere, which is closely connected with its other parts. Some organisms remain in the soil their entire life, others - half. For plants, soil plays a vital role. What living organisms have mastered the soil habitat? It contains bacteria, animals, and fungi. Life in this environment is largely determined by climatic factors such as temperature.

Adaptations for soil habitats

For a comfortable existence, organisms have special body parts:

small digging limbs;
long and thin body;
digging teeth;
streamlined body without protruding parts.

The soil may lack air and be dense and heavy, which in turn has led to the following anatomical and physiological adaptations:

strong muscles and bones;
resistance to oxygen deficiency.

The body coverings of underground organisms must allow them to move both forward and backward in dense soil without problems, so the following characteristics have evolved:

short wool, resistant to abrasion and able to be ironed back and forth;
lack of hair;
special secretions that allow the body to slide.

Specific sense organs have developed:

the ears are small or completely absent;
there are no eyes or they are significantly reduced;
tactile sensitivity has become highly developed.

It is difficult to imagine vegetation without soil. Distinctive feature The soil habitat of living organisms is considered to be that creatures are associated with its substrate. One of the significant differences in this environment is regular education organic matter, as a rule, due to dying plant roots and falling leaves, and this serves as a source of energy for the organisms growing in it. The pressure on land resources and environmental pollution negatively affect the organisms living here. Some species are on the verge of extinction.

Organismal environment

The practical impact of humans on the environment affects the size of animal and plant populations, thereby increasing or decreasing the number of species, and in some cases, their death. Environmental factors:

biotic - associated with the influence of organisms on each other;
anthropogenic - associated with human influence on the environment;
abiotic - refers to inanimate nature.

Industry is the largest sector in the economy modern society plays a vital role. It affects the environment at all stages of the industrial cycle, from the extraction of raw materials to the disposal of products due to their further unsuitability. Main types negative influence leading industries on the environment of living organisms:

Energy is the basis for the development of industry, transport, Agriculture. The use of almost every fossil (coal, oil, natural gas, wood, nuclear fuel) negatively affects and pollutes natural systems.
Metallurgy. One of the most dangerous aspects of its impact on the environment is considered to be the technogenic dispersion of metals. The most harmful pollutants are: cadmium, copper, lead, mercury. Metals enter the environment at almost all stages of production.
The chemical industry is one of the dynamically developing industries in many countries. Petrochemical production emits hydrocarbons and hydrogen sulfides into the atmosphere. The production of alkalis produces hydrogen chloride. Substances such as nitrogen and carbon oxides, ammonia and others are also released in large volumes.

Finally

The habitat of living organisms influences them both directly and indirectly. Creatures constantly interact with the environment, receiving food from it, but at the same time releasing the products of their metabolism. In the desert, the dry and hot climate limits the existence of most living organisms, just as in the polar regions, only the hardiest representatives can survive due to the cold. In addition, they not only adapt to a particular environment, but also evolve.

Plants release oxygen and maintain its balance in the atmosphere. Living organisms influence the properties and structure of the earth. Tall plants shade the soil, thereby helping to create a special microclimate and redistribute moisture. Thus, on the one hand, the environment changes organisms, helping them improve through natural selection, and on the other, the species of living organisms change the environment.

Having explained the origin of species on the basis of natural selection as a grandiose and all-encompassing process of successive changes in adaptations, Darwin's theory also explained the phenomenon of the purposeful structure of organic forms. The forms of devices as a reflection of expediency are infinitely varied: the swim bladder in the body of a fish is filled with air and lightens the weight of its body; it is more convenient to cross swamps on long legs with widely spaced toes, like a heron, or with wide hooves, like an elk; Jumping animals have more developed hind limbs (kangaroo, grasshopper, frog). Animals that lead an underground lifestyle have spade-shaped limbs and are adapted for digging the ground. There are expedient adaptations in plants and animals to daily and annual fluctuations in temperature and humidity.

Adherents of idealistic views and ministers of the church saw in the phenomena of the adaptability of organisms and their purposeful structure an expression of the general harmony of nature, supposedly emanating from its creator. C. Darwin's theory rejects any participation in the emergence of adaptations of supernatural forces; it convincingly proved that all animals and vegetable world Since its appearance, it has been improving along the path of expedient adaptations to living conditions: water, air, sunlight, gravity. The amazing harmony of living nature, its perfection is created by nature itself: the struggle for survival. This struggle is the force that gives strength to roots, sophisticated beauty to flowers, causes a bizarre mosaic of leaf arrangement and sharpens teeth, gives powerful muscle strength, visual acuity, hearing and sense of smell to many animals.

Adaptability as an expression of expediency is manifested in everything. For example, predators have claws, fangs, beaks, and poisonous teeth, from which it can be very difficult for the victim to escape. But in the struggle for life, means of defense were also developed: some respond to force with force, others are saved by their legs, others developed shells, shells, needles, etc. Many weak and defenseless insects, being harmless or edible, long years the actions of natural selection took on the color and shape of hornets and wasps and became similar to poisonous or inedible forms. Their imitative coloring or shape is at the same time protective, since it coincides with the background of the environment: it makes predators invisible and helps them sneak up on prey, and it gives hunted species the opportunity to hide from enemies. If the insects pursued by birds were not colored to match the color of green grass or tree bark, they would be exterminated by birds. The plumage of the tundra partridge merges with the tone of the rocks and peaks covered with lichens, the woodcock is invisible among the dried and fallen oak leaves, etc. The ability of animals to take on a “threatening” or “frightening” color and pose is of a pronounced adaptive nature: the caterpillar of the wine hawk moth has eye-like spots; at the moment of danger, it raises the front part of the body, thereby scaring away the birds.

Various adaptations exclude the possibility of self-pollination in most plants, allow them to distribute fruits and seeds, or, thanks to their spines, resist being eaten by herbivores. The aroma and bright color of flowers arose as adaptations to attract insects, which, visiting the flowers, cross-pollinate these plants, or as an adaptation to more efficiently absorb sunlight of a certain length.

Protective coloration. Protective coloration is developed in species that live openly and may be accessible to enemies. This coloration makes the organisms less noticeable against the background of the surrounding area. Some have a bright pattern (the coloring of a zebra, tiger, giraffe) - alternating light and dark stripes and spots. This dismembering coloration seems to imitate the alternation of spots of light and shadow.

Disguise. Camouflage is a device in which the body shape and color of an animal blends in with surrounding objects. For example, the caterpillars of some butterflies resemble twigs in body shape and color.

Mimicry. Mimicry is the imitation of a less protected organism of one species by a more protected organism of another species. This imitation can manifest itself in body shape, coloring, etc. Thus, some types of non-venomous snakes and insects are similar to poisonous ones. Mimicry is the result of selection of similar mutations in various types. It helps unprotected animals survive and helps preserve the body in the struggle for existence.

Warning (threatening) coloring Species often have bright, memorable colors. Having once tried to taste an inedible ladybug or a stinging wasp, the bird will remember their bright color for the rest of its life.

(Based on materials from Andrey Ivanov’s personal page)

In the doctrine of natural selection, Darwin not only materialistically substantiated the fitness of organisms (their expedient structure), but also showed its relative nature. Thus, warning and protective coloring and various other protective devices do not affect all pursuers, but, having devices, individuals are less likely to be attacked. Those with stings - wasps, bees, hornets - are easily eaten by flycatchers and bee-eaters. A flying fish, jumping out of the water into the air, deftly escapes from predatory fish, but the albatross takes advantage of this, overtaking its prey in the air. The tortoise's shell is a good defense, but the eagle lifts it into the air and throws it onto the rocks; the shell breaks and the eagle eats the turtle.

Every animal and plant cannot be fully adapted to all conditions that have developed throughout life on Earth. Any adaptation persists as long as it is supported by natural selection, but disappears as soon as it ceases to be useful. As an example of a change in adaptations, one can cite the development of protective coloration in the birch moth butterfly.

Thus, the basis of Darwin's theory is the doctrine of natural selection - the main and guiding factor of evolution. In the struggle for existence based on hereditary variability, sequential shift adaptations and the survival of the fittest, the diversity of forms of living nature increases, the process of speciation occurs and the general progressive development of the plant and animal world takes place. In this theory, two problems were resolved: the mechanism of speciation and the origin of the purposiveness of the organic world.

Adaptability of organisms as a result of evolution (T.A. Kozlova, V.S. Kuchmenko. Biology in tables. M., 2000)

Fitness indicators	Plants	Animals
Methods of obtaining food	The absorption of water and mineral salts is ensured by the intensive development of roots and root hairs; absorption of solar energy is carried out most successfully by wide and thin leaves; capture and digestion of insects and small amphibians by marsh plants	Eating leaves on tall trees; capture using a trap net and lying in wait for food items; the special structure of the mouthparts ensures catching insects from long, narrow burrows, biting grass, and catching flying insects; Grasping and holding prey predatory mammals and birds
Anti-eating	They have spines that provide protection from herbivores; contain toxic substances; the rosette shape of the leaves is not available for grazing	They escape by running quickly; have needles, shells, a repellent odor, and other protection; protective coloring saves in certain conditions
Adaptation to abiotic factors (cold)	Falling leaves; cold resistance; preservation; vegetative organs in the soil	Flight to the south; thick coat; hibernation; subcutaneous fat
Expansion into new territories	Light, winged seeds; tenacious hooks	Bird flights; animal migration
Reproduction efficiency	Attracting pollinators: flower color, smell	Attracting a sexual partner: bright plumage, sexual attractants

Biology knows many cases when a group that accidentally splits off from the main population can, after a few centuries, form a completely the new kind. Sometimes it even happens that individuals of the maternal species continue to live in the same territory.

There are also many examples where species are forced to live in a constantly changing external environment. Often, “change” refers to a permanent deterioration in some vital sign. When going beyond this range, the species most often simply goes extinct.

Prerequisites for survival

Scientists have come to the conclusion that the species has a chance of survival only if it begins to actively change, adapting to dramatically changed conditions. This phenomenon is called phyletic speciation. In this case, not only the adaptability of organisms to their environment is formed, but also completely new characteristics for living beings develop.

There are currently millions of species living on our planet. Isn't this evidence of the power of life, its constant variability?! Unfortunately, several million years ago there were much more living creatures. Several ice ages and constant climate fluctuations have led to a sharp decline in species diversity. Only the most adaptable survived.

Important examples of adaptations

From time immemorial, the ingenious correspondence between the organs of living beings and the function they perform has attracted the attention of people: attempts to create gliders with a bird-shaped wing, the construction of ships with contours resembling bodies sea fish. But what is much more striking is the ideal, harmonious correspondence appearance animals and plants with their natural habitat.

Of course, the examples can be continued endlessly. Therefore, within the framework of this article, it is possible to talk about only some living beings, whose features of adaptability to their environment most clearly and clearly prove Darwin’s correctness.

Birds

Thus, people have long known about the importance of protective coloring for birds, as well as their chicks and eggs in particular. In wood grouse, black grouse and partridges (which nest openly), the shells of eggs blend almost perfectly into the background of the surrounding area. In general, the female’s back is also indistinguishable from the surrounding landscape when viewed from the side. All the more interesting is the fact that the females and eggs of birds that nest in hollows and other hidden places often have very bright colors (the same parrots, for example).

Insects

What features of adaptation to the environment do insects have? Well, they are even more numerous than all the representatives of this class. We think that everyone knows the striking similarity between stick insects and dry twigs. Some research in this area is still used by the military in the creation of “forest” camouflage suits.

However, the bodies of many caterpillars closely resemble twigs, and the wings of butterflies can pass for the leaves of trees in the area where they live. It should be noted here that in this case there is a harmonious combination of a protective body shape and a protective coloring. Some butterflies, when they blend into their surroundings, are difficult to distinguish from leaves even at point-blank range. If you know biology more or less, then you have a great idea of the diversity of the insect class. When you get into a forest or field, you see no more than 2-3% of their total number. The rest are simply disguised.

But! One should not assume that examples of organismal adaptation are limited to banal camouflage. Remember about adaptive coloration, when brightly colored, “colorful” insects are not popular with predators, since they are well aware of their sharply negative nutritional qualities. Thus, a tit or a sparrow, having tried to eat a soldier bug a couple of times in their youth, remembers their caustic, poisonous taste for the rest of their lives.

In addition, features of organisms’ adaptation to the environment include mimicry. This phenomenon resembles a patronizing connotation, but “on the contrary.” Thus, some defenseless and edible species can perfectly imitate those insects that are poisonous or have a disgusting taste. For example, wasp flies are very similar to wasps, which even many birds are afraid of. All this suggests that the adaptability of organisms to environmental conditions is precisely adaptive, adaptive in nature.

Higher mammals

All this can be seen in the example of higher mammals. The coloring of zebras seems bright and even somewhat ridiculous to us, but it perfectly follows the alternation of light and shadow in the grass thickets, which allows these animals to camouflage perfectly in the savannah. Eyewitnesses confirm that untrained people sometimes do not notice zebras even in open areas, from a distance of only 50-70 m.

Other Features

Some living creatures have an even more amazing and effective adaptation. We are talking about chameleons and flounder, which can change the color of their body by redistributing organic pigments in the chromatophores of the skin. Do not forget that protective coloring and other protective factors dramatically improve their effectiveness provided that they behave accordingly. This includes the freezing reflex, adopting a resting pose, which is typical for a huge number of animal species.

Where do living beings have this ability?

In general, where did the adaptation of organisms to their environment come from? In general, in the previous part we already expressed the opinion of the great Darwin: if an animal or plant can survive a sharp change in climate or other conditions, then its descendants will become the most common. Thus, the main reason for the emergence of some new adaptations in living beings is precisely natural selection. Let's illustrate this with a practical example by discussing the life of the family of grouse birds that live in the lower canopy of the forest.

Structural features

Let's remember the main features external structure these birds: the beak is short, does not interfere with pecking food directly from the forest floor (including from the snow cover); on their paws there is a thick fringed backing, with the help of which they can walk calmly even in deep snow. The structural features of the feather allow them to spend the night with their heads buried in the snow, and short, wide wings make black grouse few of the birds that can take off directly, almost vertically.

It would be quite logical to assume that their distant ancestors had no trace of such devices. Most likely, after a number of environmental factors changed (it simply got colder), they were forced to adapt to a dramatically changed habitat, including cold.

Change process

New mutations constantly arose, their various combinations occurred during crossing, and wave numbers made the population more heterogeneous and stable. It is not surprising that the birds were distinguished from each other by a number of characteristics: some had fringes on their fingers, some individuals had a shortened beak or wings.

What was the adaptation of organisms to their environment? The fact is that during the constant process, only those birds survived whose structural parameters were most consistent with the surrounding world. During the selection process, only they left more offspring, and it was they who survived most often and in quantities sufficient to form a new population. The new generation brought with it new mutations and the whole process was repeated from the very beginning.

Consolidation of useful traits and qualities

Surely among the mutations there were those that strengthened and consolidated the manifestation of signs that had appeared earlier. Naturally, the birds that exhibited these changes had a significantly greater chance of not only surviving, but also subsequently producing offspring. Over the course of generations, all these characteristics accumulated and became fixed until the grouse we know today appeared.

Contradictions of Lamarck's theory

As is known, Darwin's theory is fundamentally different from the assumption put forward by Jean Baptiste Lamarck. The latter said that all living organisms can change under the influence of the environment, but only in the direction that is exclusively beneficial for them. But this is absurd: what kind of influence could have contributed to the appearance of spines in hedgehogs?

Only the influence of natural selection can explain the emergence of such a useful adaptation. It is assumed that the very distant ancestors of hedgehogs were able to survive, becoming covered with increasingly coarsening hair. Staying alive and producing offspring was an advantage for those “proto-hedgehogs” who were lucky enough to have the longest and toughest spines.

Other “prickly” examples

“Bristly hedgehogs” from Madagascar followed exactly the same path. We are talking about tenrecs and a few species of spiny-haired mice and hamsters.

Does the adaptability of organisms to their environment have at least some general signs? Scientists suggest that the mechanism for the emergence of this kind of adaptation remains common in all cases: the fact is that they do not appear immediately, not in one or two generations. On the contrary, their emergence is a long and complex process. We should never forget that the evolutionary path is full of dead-end branches and unsuccessful “technical solutions” of nature. This is what we will talk about now.

Relativity of fitness

In the period before Darwin, the adaptability of animals to their environment served as unanimous proof of the existence of God and the immeasurable wisdom of the Creator: how could nature, without such “guidance,” organize itself independently? the world in such a reasonable, balanced way!?

The prevailing opinion was that every feature of any living organism was absolutely perfect and exactly corresponded to the task that was assigned to it. Thus, an elongated proboscis helps her obtain nectar from even the most “complex” flowers, and the plants’ adaptation to the habitat in the form of thick trunks of cacti and other succulents are ideally suited for storing water for a long time.

Unfortunately, even many modern scientists continue to treat nature as a brilliant sculptor, each of whose creations is perfect and infallible. But! It is important to clearly realize that this is far from the case!

Modern studies of adaptation to the environment have shown that any changes are always relative, since they are formed much more slowly than the actual changes in environmental conditions. Accordingly, many traits may turn out to be unnecessary, or even directly harmful to the body, if the world around changes.

Evidence of relativity

Proof of the fact that the fitness of living organisms is a very, very relative concept is provided by the following examples:

Protective devices are very effective against some enemies, but they are not particularly good at saving animals from other enemies. Cone snails eat with pleasure, and the cuckoo includes poisonous hairy caterpillars in its diet.
Not all animal reflexes are truly appropriate and adequately correlate with environmental conditions. Remember about moths that collect pollen from light flowers that are clearly visible at night: they just as quickly fly towards the flames of fires and candles, although they die in the process.
Organs of adaptation that are truly useful in one environment turn out to be harmful and even dangerous in other conditions. So, those who have never been in the water in their lives have webbed paws.
Beavers, one of the best “engineers” in nature, actively build dams even in stagnant ponds and pools, which is a waste of energy.

Relativity is especially pronounced in the case of those animals whose homeland is located at the other end Globe, but which were brought by humans into a completely new habitat for them. Simply put, it is the most revealing and convincing proof that nature is not always infallible.