How to explain the emergence of adaptations in organisms. Biology lesson

Adaptation is understood as a set of morphophysiological, behavioral, population and other features of a given biological species, which provides the possibility of its existence in certain conditions external environment.

General adaptations - adaptations to life in a wide area of ​​the environment ... General adaptations include, for example, the adaptation of the limbs of vertebrates to the terrestrial environment (most reptiles, mammals), swimming (fish, whalesdifferent, sea ​​turtles etc.), flight (birds, bats mammals).

Private adaptations - specializations for a specific lifestyle ... The adaptations of the private plan include, for example, the fitness of the limbs of vertebrates for running (antelopes, horses, ostriches, etc.), a burrowing way of life (moles, moggers, zokors, mole rats, etc.), climbing trees (monkeys, sloths, woodpeckers, piscuhi, etc.), different types flight (vultures, falcons, albatrosses, ducks, etc.; different wing structures are considered as adaptations to specific types of flight), various typesswimming pam (sharks, sea turtles, penguins, seals). Many examples of private adaptation are associated with the presence of a so-called protective coloration in animals.

There are conventionally distinguished several types of patronizing coloration (sometimes forms): disguise, mimicry, demonstration.

Disguise

Wasp fly imitates a wasp (mimicry)

Demo example

There are many transitions between the selected types.

Disguise is a device in which the shape of the body and color of animals merge with the surrounding objects. For example, the caterpillar of the moth butterfly looks like a twig, the stick insect looks like a dry branch, the Australian rag fish - on the coastal algae, distinguish the following main types of camouflage coloration: cryptic (provides similarity to the surrounding background); dismembering ("blurs" the contour of the animal; characteristic of the eggs, and sometimes the birds themselves, nesting openly on the ground - waders, ducks, nightjars, etc.); concealing (based on the principle of "counter-shadow").

Concealing coloring is especially important for the protection of the body in the early stages. individual development(eggs, larvae, chicks, baby mammals, etc.). In open nesting birds, females have this color, which is especially necessary during the period of incubation of the clutch. Dismembering coloration can be predators using long-term tracking of prey: tiger, leopard, jaguar, perch, etc. Some animals are capable of a rapid color change depending on changes in the surrounding background, for example different kinds flounders, chameleons.

Mimicry - the similarity of the defenseless and edible with one or more representatives of unrelated species, well protected from attack and eating by a predator (mimeticism) or plants and objects environment(mimesia). Various forms of mimetism are characteristic of a number of insect species (flies imitate wasps, bumblebees), snakes ( non-venomous snakes imitate the color and behavior of poisonous). Textbooks the following examples mimesias: some seahorses, such as the rag-horse, resemble algae; eggs of some waders (oystercatchers, plovers) are similar in color and shape to pebbles (nesting birds are closed, for example, in hollow nests, eggs are unpainted); the caterpillar of a moth butterfly resembles a dry twig; a stick insect looks like dry twigs; the name fish-leaf speaks for itself; some butterflies look like dry leaves and even imitate their fall during flight, etc.

There are two forms of mimicry: Bates's (named after G. Bates) and Müller's (F. Müller). An example of Bates's mimicry is the case of the similarity of certain species of butterflies to the whites with edible, brightly colored and foul-smelling heliconid butterflies. In the variant of Müllerian mimicry, several protected species of animals have a similar appearance and color - they form a set of species, called a "ring". So, many types of wasps are similar to each other. Poisonous insects(soldier bug, blister beetle, seven-point ladybug) have a frightening color - red with black spots. Insectivorous birds, developing a "disgust reflex" on one species, no longer touch the "ring" species.

Mimicry in plants serves to scare away or attract animals. For example, belozor flowers devoid of nectar are similar to melliferous flowers and likewise attract pollinating insects. The trapping devices of carnivorous plants "imitate" bright flowers other types and suchtrap insects in a way. It is believed that the emergence of mimicry is associated with the selective extermination of animals or plants.

Demonstration (threatening or warning coloration or form). An animal with poisonous teeth (poisonous snakes), a stinging device (stinging hymenoptera: bees, wasps), poisonous skin glands (amphibians: fire salamander, toads, etc.) usually "broadly announce" about it. Such specieshave a frightening color (Müllerian mimicry) or a special "pattern" (for example, in some snakes), which are well remembered by other animals. Row poisonous snakes notifies of its presence not so much by color as by sounds,

mainly of the so-called instrumental nature, i.e. emitted either by friction of scales (efa), or by means of a special "rattle" at the tip of their tail (rattlesnakes).

The origin of adaptations and their relativity ... Evolution is about the acquisition of gadgets. The priority of the scientific explanation of cases of adaptation of animals and plants belongs to Charles Darwin. J. B. Lamarck believed that organisms have an innate ability to change under the influencethe external environment and only in a direction useful to them. It is unlikely that the appearance of spines of porcupines, hedgehogs, tenrecs (Madagascar bristly hedgehogs) is directly related to the manifestation of environmental conditions. Charles Darwin showed that adaptations arise as a result of the action natural selection... Only those with sharper and stronger thorns survived the fight against predators and could leave viable offspring. So, from generation to generation, those beneficial hereditary changes that contributed to the preservation and prosperity of the species were accumulated and consolidated.

As a result historical development living beings, their entire organization turns out to be deeply adaptive. However, the adaptability of organisms to the environment, despite all its perfection, is not absolute, but relative. The relativity of adaptations is primarily associated with the fact that the conditions of the external environment often change much faster than the formation of certain adaptations. And already existing adaptations lose their value for the organism in a transformed environment.

The following examples provide evidence of the relativity of adaptations:

1) an organ useful in some conditions becomes useless and even relatively harmful in another environment: the relatively long wings of the swifts, adapted for rapid, long flight, create certain difficulties when taking off from the ground; long wings of a seabird - a frigate do not allow it to rise from the smooth surface of the sea; the wandering albatross is unable to take off from the deck of the ship;

2) protective devices from enemies are also relative: poisonous snakes (for example, vipers) are eaten by hedgehogs, pigs, which are not susceptible to their poison; large lizard- gray monitor lizard - not susceptible to cobra venom;

3) the manifestation of instincts may also turn out to be inappropriate: for example, a defensive reaction (releasing a jet of a foul-smelling liquid) of a skunk directed against a walking car (unfortunately, it happens that for this reason these animals die on the roads of the USA);

4) the observed "overdevelopment" of some organs, which become a hindrance to the body (the phenomenon of hypermorphosis): huge (up to 3 m and more in span) antlers of the extinct big-horned deer (Megaceros eurycerus); overdeveloped babirusa (wild pig) canines; fearsome dagger fangs of the extinct saber-toothed tigers(mahairods, smilodons), excessively long tusks of ancient proboscis — mastodons.

Evolution organic world - Tutorial(Vorontsov N.N.)

The emergence of adaptations is the result of the action of natural selection

Correspondence of the structure of organs to the functions performed (for example, perfection aircraft birds, bats, insects) has always attracted the attention of man and prompted researchers to use the principles of organizing living beings when creating many machines and devices. The harmonious relationship of plants and animals with their habitat is no less striking.

The facts testifying to the adaptability of living things to living conditions are so numerous that it is not possible to give any complete description of them. Here are just a few striking examples of adaptive coloration.

Examples of adaptation. Protective coloration is especially important for the protection of eggs, larvae, chicks. In open nesting birds (wood grouse, eider, black grouse), the female sitting on the nest is almost indistinguishable from the surrounding background (Fig. 26). The pigmented eggshells also match the background. It is interesting that in birds nesting in the hollow, the females often have bright colors (tits, woodpeckers, parrots).

A surprising resemblance to twigs is observed in stick insects. Caterpillars of some butterflies resemble knots, and the body of some butterflies resembles a leaf (Table 7). Here, patronizing coloration is combined with patronizing body shape. When the stick insect freezes, it is difficult to detect its presence even from close range - it merges so much with the surrounding vegetation. Whenever we find ourselves in the forest, in the meadows, in the field, we do not even

Rice. 26. The motley color of the eider hides it from enemies

we notice how many insects are hiding on the bark, leaves, in the grass.

In zebra and tiger, dark and light stripes on the body coincide with the alternation of shadow and light of the surrounding area. In this case, animals are hardly noticeable even in open space from a distance of 50-70 m. Some animals (flounder, chameleon) are even capable of a rapid change in protective color due to the redistribution of pigments in the chromatophores of the skin. The effect of protective coloration increases when it is combined with appropriate behavior: at the moment of danger, many insects, fish, birds freeze, taking a resting pose.

A very bright warning coloration (usually white, yellow, red, black) is characteristic of well-protected, poisonous, stinging forms. Having tried several times to taste the cloe-pa-"soldier", ladybug, wasp, the birds finally refuse to attack the victim with a bright color.

Interesting examples of adaptation are associated with mimicry (from the Greek. Mimos - actor). Some defenseless and edible animals mimic species that are well protected from predators. For example, some spiders resemble ants, and wasp flies are outwardly similar to wasps (Table 7).

These and many other examples speak of the adaptive nature of evolution. What are the reasons for the emergence of various adaptations?

The origin of fitness (adaptation) in organisms. For the first time, a scientific explanation of fitness was given by Charles Darwin. From the very Darwinian doctrine of natural selection, as the process of survival and reproduction of the fittest, it follows that selection is the main reason for the emergence of various adaptations of living organisms to their environment.

Let us show this by the example of the formation of adaptations in grouse birds to life in the lower layer of the forest. To do this, remember some of the features external structure and the way of life of these birds: a short beak, which allows pecking berries and seeds from the forest litter, and in winter from the surface of the snow, horny fringes on the fingers, providing walking in the snow, the ability to escape from the cold, burying in the snow at night, short and wide wings, making it possible to quickly and almost sheer take off from the ground.

Let us assume that the adaptations described above were not developed in the ancestors of grouse birds. However, when the habitat changed (due to a cold snap or due to some other circumstances), they were forced to winter in the forest, nest and feed on the forest floor.

The continuous process of the emergence of new mutations, their combination during crossing, and waves of abundance ensured the genetic heterogeneity of the population. Therefore, the birds differed from each other in a number of hereditary characteristics: the absence or presence of fringes on the fingers, the size of the wings, the length of the beak, etc.

The intraspecific struggle for existence contributed to the survival of individuals in which the signs of the external structure were more consistent with the living conditions. In the process of natural selection, it was these birds that left fertile offspring and their number in the population increased.

Birds of the new generation again carried a variety of mutations. Among the mutations there could be those that enhanced the manifestation of previously selected traits. The owners of these traits again had a better chance of surviving and leaving offspring. And so, from generation to generation, on the basis of amplification, accumulation of beneficial hereditary changes, the features of the adaptation of grouse birds to life in the lower tier of the forest were improved.

The explanation of the emergence of fitness, given by C. Darwin, is fundamentally different from the understanding of this process by J. B. LaMarc, who put forward the idea of ​​the innate ability of organisms to change under the influence of the environment only in a direction useful to them. All known hedgehogs have sharp thorns that reliably protect them from most predators. It is difficult to imagine that the formation of such spines is caused by the direct influence of the environment. Only the action of natural selection can explain the emergence of such a device: even a slight coarsening of hair could help the distant ancestors of the hedgehog to survive. Gradually, over millions of generations, only those individuals remained alive, which by chance turned out to be the owners of more and more developed thorns. It was they who managed to leave offspring and pass on their hereditary characteristics to him. Madagascar went along the same path of the emergence of needles instead of hair

"Bristly hedgehogs" - tenrecs and some spiny-haired species of mice and hamsters.

Considering other examples of adaptation in living nature (the appearance of thorns in plants, various hooks, hooks, flies in plant seeds in connection with their spread by animals, etc.), we can assume that the mechanism of their occurrence is common: in all cases, adaptations arise not immediately in a finished form as something given, but for a long time are formed in the process of evolution through the selection of individuals that have a characteristic in the most pronounced form.

Fitness relativity. In the pre-Darwinian period of the development of biology, the fitness of living beings served as proof of the existence of God: without an omnipotent creator, nature itself could not so reasonably arrange living things and so wisely adapt them to the environment. The prevailing opinion was that each individual device is absolute, since it corresponds to a specific goal laid down by the creator: the mouth parts of the butterfly are extended into the proboscis so that they can get the nectar hidden in the depth of the rim; a thick stem of a cactus is necessary for storing water, etc.

The adaptation of organisms to the environment is developed in the process of long historical development under the influence of natural causes and is not absolute, but relative, since the conditions of the environment often change faster than adaptations are formed. Corresponding to a specific habitat, adaptations lose their meaning when it changes. The following facts can be evidence of the relative nature of fitness:

Protective devices against some enemies are ineffective against others (for example, poisonous snakes, dangerous for many animals, are eaten by mongooses, hedgehogs, pigs);

The manifestation of instincts in animals may turn out to be inappropriate (moths collect nectar from light flowers, clearly visible at night, but they also fly into the fire, although they die at the same time);

An organ useful in some conditions becomes useless and even relatively harmful in another environment (membranes between the toes of mountain geese, which never sink into the water);

More perfect adaptations to this habitat are also possible. Some species of animals and plants multiplied rapidly and spread widely in completely new areas for them. the globe, where they were accidentally or deliberately brought by man.

In this way, relative character fitness contradicts the assertion of absolute expediency in living nature.

CHECK YOURSELF

1. Give your examples of the adaptability of organisms to the environment.

2. A discussion arose about the results of natural selection. Some argue that fitness in the structure and. the behavior of organisms of any kind has already reached the limit, there will be no further improvement of modern species. Others express the opposite opinion: the adaptations of species are not always perfect, and environmental conditions are constantly changing, so that selection can always continue where there is life. What is your opinion? Based on what facts can you end the dispute?

3- How to explain the appearance of rudimentary eyes in a mole?

4. How is the woodpecker adapted to life in trees? Explain the origin of some device, such as a chisel-shaped beak.

5. What is the relative fitness of plantain, nettle, dandelion?

LESSON DEVELOPMENT ON THE TOPIC

APPARATUS APPARATUS

Today we will talk with you about the adaptation of organisms to the conditions of existence. Let us find out what adaptation is and what types of adaptations exist, define the main types of adaptations in nature and select examples for them. Adaptations to environmental conditions are the result of natural selection, so let's remember:

1.what is natural selection?

Survival and reproduction of the fittest organisms.

2. What forms of natural selection do you know?

Motive, disruptive, stabilizing.

3. What is driving selection?

- a form of natural selection that acts in a directional change in environmental conditions.

4. What is an example of driving selection?

Dark coloration of the birch moth butterfly in industrial areas

5. What is disruptive selection?

A form of natural selection in which conditions favor two or more extreme variants (directions) of variability, but do not favor an intermediate, average state of the trait.

6. Give an example.

Two races in a large rattle in hay meadows, polymorphism of 2 forms of flowers of ladybugs

7. What is stabilizing selection?

Stabilizing selection is a form of natural selection; individuals with traits that do not deviate from the norm are preserved.

8. Give an example

Average number of chicks in the nest, optimal sizes and the shape of flowers and inflorescences in insect pollinated plants.

And now we open notebooks and write down the theme: "The emergence of adaptations."

As a result of natural selection, plants and animals develop adaptations corresponding to the environment in which they are constantly encountered. It is known that birds have flight devices - wings. Such adaptations to the conditions of existence have long attracted the attention of man. No wonder they say that "wings are given to a bird for flight." TO aquatic environment perfectly adapted fish. Here it is appropriate to recall the expression: "to feel like a fish in water."

Now let's write down what adaptation is. Adaptation is understood as a set of morphophysiological, behavioral, population and other characteristics of a biological species, which ensures the possibility of its existence in certain environmental conditions. Usually adaptations are distinguished into general and specific.

General adaptations are adaptations to life in a wide area of ​​environmental conditions. An example is the adaptation of the limbs of vertebrates to the terrestrial environment.

Private adaptations are adaptations to a particular lifestyle. Examples would be the ability of monkeys to climb trees, or the ability of sharks to swim.

Many examples of private adaptations are associated with the presence in animals of the so-called protective coloration, which is conventionally divided into several types: disguise, mimicry, demonstration.

You will get to know each type of patronizing coloration in more detail while working with the text.

We are divided into 3 groups, each group answers 4 questions that lie in front of you. Take notes of the answers in your notebook. Then each representative from the group dictates their answers to the other groups, and the rest write down.

Now we will check how you learned this topic, before you are illustrations - you need to name what form of patronizing coloration is presented in the illustration.

QUESTIONS

1. What is disguise?

2. What types of disguises are there?

3. What is an example of disguise?

4. What is the value of camouflage coloring?

DISGUISE

Disguise is a device in which the shape of the body and color of animals merge with the surrounding objects. There are several types of camouflage: cryptic, dismembering, hiding. The cryptic coloration (K. o.) Of the animal ensures the similarity of the individual with the surrounding background. Animals living in the grass are green (lizards, grasshoppers, caterpillars), desert dwellers are yellow or brown (desert locust, eared roundhead, saiga). Disruptive, or dismembered, coloration is characterized by the presence of contrasting spots and stripes that violate the visual impression of the contours of the body, as a result of which the animal becomes invisible against a background with alternating spots of light and shadow. Disruptive coloration is often combined with cryptic, that is, spots in the color of the animal are in harmony with the background. Disruptive coloration is characteristic of many animals (locusts, butterflies, barbel beetles, lizards, chipmunks, zebras). Creeping coloration is based on the counter-shade effect: the most brightly illuminated parts of the body are colored darker than the less illuminated ones: the coloration seems to be more monotonous, and the outlines of the animal merge with the background. This color ("dark back - light belly") is typical for most fish and other inhabitants of the water column, for many birds and some mammals (deer, hares).

QUESTIONS

1. What is mimicry?

2. What types and forms of mimicry exist in nature?

3. Give examples of each of the types and forms of mimicry?

4. What is the significance of mimicry?

MIMICRY

Mimicry is the resemblance of a defenseless and edible animal to one or more members of an unrelated species. In nature, 2 types of mimicry are distinguished: mimetism - similarity with another animal and mimesia - similarity with plants and environmental objects. Various forms of mimetism are characteristic of a number of insect species - flies mimic wasps. Textbook examples of mimesia are some seahorses, for example, the rag-horse resembles algae.

There are 2 forms of mimicry: Bates, described by G. Bates and Müller, described by F. Müller. An example of Bates's mimicry is the case of the similarity of certain species of white butterflies with inedible, brightly colored and foul-smelling heliconid butterflies. In a variant of Müllerian mimicry, several protected species have outward resemblance and coloring, for example, some species of wasps.

There are many animals using both defense mechanism sound imitation. This phenomenon is mainly found among birds. For example, a rabbit owl, living in rodent burrows, can mimic the hissing of a snake.

Mimicry in plants serves to scare away or attract animals. For example, belozor flowers, devoid of nectar, are similar to honey flowers and similarly attract pollinating insects. It is believed that the emergence of mimicry is associated with the selective extermination of animals or plants.

QUESTIONS

1. What is a demo?

2. What are some examples of threatening colors or shapes?

3. What are some examples of warning colors or shapes?

4. How important is the demonstration?

DEMONSTRATION

Demonstration - the shape or color of animals that makes them noticeable against the background of the environment. There are two types of demonstration: menacing and patronizing form or color. Threatening coloration is very different from the background of the environment, is shown suddenly in danger and is usually combined with a threatening posture and sounds. For example, some species of butterflies (from the genera of hawk moths, tapeworms), cicadas, locusts, praying mantises, etc. have ocular spots or bright bands on their hind wings. Warning coloration, a type of protective coloration and form in which inedible animals have a bright, usually variegated, coloration. Such animals are clearly visible due to contrasting color combinations (black, red, white; orange, white, black, etc.). Among vertebrates, warning coloration is inherent in some fish, salamanders, toads, toads.

A number of poisonous snakes notify of their presence not so much by color as by sounds, mainly of the so-called instrumental nature, i.e. emitted either by friction of scales, or by means of a special "rattle" at the end of the tail (rattlesnakes).

The demonstration provides the animals with visibility, which is an advantage because, once recognized, they are not attacked by predators.

Ending. See No. 21/2006

The fitness of organisms is the result of the action of evolutionary factors.
The relative nature of adaptations

11th (9th) grade (2 hours)

Lesson 2. The mechanism of the emergence of adaptations and their relative nature

Methodological support

In the second lesson on this topic, elements of group technology are used mental activity. Target its applications:

- enhancing the mental activity of students in the classroom;
- development of the ability to apply knowledge in a new situation;
- the formation of skills to establish cause-and-effect relationships.

Applied teaching techniques: "Clusters"; “Thought in a circle”; work on the algorithm; "Business card report".

Stages of work:

- checking homework;
- motivation for learning activities: creating problem situation, individual work students;
- teacher's story; teaching students a scheme for analyzing the mechanisms of the emergence of adaptation;
- joint discovery of knowledge (student activities: division into groups; work in groups on the instructions of the teacher (as a variant of laboratory work), teacher activities: correction of students' answers, direction of the work of groups);
- independent application of knowledge: presentation of their material by each group and brainstorming;
- summing up the lesson ("Business card report", joint formulation of conclusions, students making changes to their notes).

Planned result: show the need to know the mechanisms of the emergence of adaptations to explain the action of natural selection.

Lesson grades: for homework; for the performance from the group; for the "Business card report"; for laboratory work - based on the results of checking notebooks.

Lesson materials:

- didactic cards with statements corresponding to the points of view of Linnaeus, Lamarck, Darwin;
- schemes for analyzing the mechanisms of the emergence of adaptation for each group;
- tables, live objects or herbaria and stuffed animals for laboratory work.

DURING THE CLASSES

To live is to react, not to be a victim.

Homework check

Option 1. Mutual adaptations of predators and prey.

Predators

Development of organs for capturing, holding, killing prey (teeth, beak, claws).

Concealing coloring.

Development of organs for pursuit (fast and agile running, swimming or flying).

Isolation of paralyzing poisons.

Development of special ways of behavior (pursuit, waiting in ambush).

Weaving trapping nets (for example, spider webs).

Victims

Development of defense organs (sting, needles).

Development of mechanical defense organs (carapace).

Protective coloration or deterrent patterns (eg "eyes").

Development of organs to escape the predator (fast and agile running, swimming or flying).

Release of poisons, repelling and irritating odors.

Development of special ways of behavior (hiding, fast movement).

Construction of shelters (for example, caddis houses).

Lack of locomotion organs and remote sensory organs.

Lack of mouth, intestines.

Special attachment organs (suction cups, hooks).

Lack of pigmentation.

Anaerobicity.

Big number descendants, there is no care for the offspring.

Change of generations, complex metamorphosis.

Change of owners.

Examples of organisms: roundworm, tapeworm, echinococcus, etc.

No active movement (eg insects without wings).

Special organs for eating (piercing proboscis, sucking organs).

Organs of attachment to the host.

Numerous offspring.

Examples of organisms: lice, fleas, leeches, bed bugs, etc.

Reduction of the organs of assimilation.

Heterotrophic type of food.

Sucking root formation.

Numerous flowers and seeds.

Motivation for learning activities

The "Cluster" technique is used (from the English. clustery- growing in bunches, brushes, bunches). This is one of the ways to organize information, usually in the form of a diagram, a working model of a situation, a tree of concepts, and a terminological map.

What factors are necessary for the emergence of adaptations? (All students' proposals are recorded on the board.)

Teacher. As you know, the most significant contribution to the development of evolutionary concepts in the XVIII-XIX centuries. contributed by K. Linney, J. B. Lamarck, Charles Darwin. Darwin's evolutionary theory served as the basis for the creation of the modern synthetic theory of evolution (STE).
Try to categorize your proposed statements into three categories:

- corresponds to the views of Linnaeus;
- corresponds to the views of Lamarck;
- corresponds to the views of Darwin (STE).

(Students work independently.)

Assertions

1. Adaptations arise as a result of new mutations.
2. The fitness of organisms is a manifestation of the original purposefulness.
3. Organisms have an innate ability to change under the influence of the external environment.
4. Adaptations are fixed by natural selection.
5. One of the driving forces of evolution is the striving of organisms for perfection.
6. Driving force evolution - the natural laws of nature.
7. One of the driving forces of evolution is the exercise and non-exercise of organs in certain environmental conditions.
8. The driving force behind the emergence of fitness is God.
9. The characters acquired in the course of interaction with the environment are inherited.

Answer: Linnaeus - 2, 8; Lamarck - 3, 5, 7, 9; STE - 1, 4, 6.

Checking the completion of the task is carried out using the "Thought in a circle" technique. The goals of this technique are: not to be afraid of mistakes; learn to listen to another; be able to analyze and summarize the material heard.

Statement numbers are written on the board, then the first student of any row (at the teacher's choice)

names whose views, in his opinion, the first statement corresponds. The answer is written in abbreviated form opposite No. 1. The survey is carried out in the same way, up to the last student. Then the number of votes for each item is calculated, the truth is determined, on the basis of which the table "The emergence of adaptations" is filled.

Table. The emergence of devices

According to Karl Linnaeus	By Jean Baptiste Lamarck	According to Charles Darwin
1. The fitness of organisms is a manifestation of the original purposefulness. 2. The driving force behind the emergence of fitness is God.	1. Organisms have an inherent ability to change under the influence of the external environment. 2. The driving forces of evolution are the striving of organisms for perfection and the exercise and non-exercise of organs in certain environmental conditions. 3. Traits acquired in the course of interaction of an individual with the environment are inherited.	1. Adaptations arise as a result of mutations and are fixed by natural selection. 2. The driving force of evolution is the natural laws of nature.

Using the data in the table, try to answer the question: what is the mechanism of the emergence of adaptations?

After the discussion, the teacher writes on the blackboard the title of the topic of the lesson and the diagram of the analysis of the mechanisms of the emergence of adaptation.

Changes are made to the original cluster: the factors most important for the formation of adaptations are framed, the rest are erased.

Teacher. In large populations, natural selection is the guiding factor of evolution, and in small populations, gene drift, the effect of which is weakened in large populations. It should be borne in mind that gene drift does not always lead to adaptation of organisms: it can even turn out to be fatal for the population, worsening its adaptability to environmental conditions.
In addition, it must be remembered that Charles Darwin emphasized that all devices, no matter how perfect they are, are relative character. Natural selection forms adaptation to specific conditions of existence (in the given time and in a given place), and not to all possible environmental conditions.
The following facts (writing in notebooks) can serve as evidence of the relativity of adaptations:

1. Protective devices turn out to be ineffective in unusual conditions: for example, when the snowfall is delayed, the white hare that has molted for the winter is clearly visible against the background of the dark ground.

2. The manifestation of instincts in animals may be impractical: for example, small birds continue to spend energy on feeding the cuckoo, which threw their offspring out of the nest.

3. Useful organs and structures for some purposes may turn out to be harmful in other conditions - for example, the wings of a swift provide it with a very fast and maneuverable flight, but do not allow it to take off if the bird accidentally ends up on the ground (swifts nest only on high cliffs); the bright coloration of the male peacock ensures his success with females, but at the same time attracts predators.

Then the teacher advises the students to make changes to the title of the topic being studied: "The mechanism of the emergence of adaptations and their relative nature."

Further, each student is randomly given a card containing an ideogram (drawing, short note) of a certain organism. The guys who received the same cards are united in groups and receive an assignment.

Exercise: using the knowledge acquired in the lesson, explain how they could arise:

- stripes on the skin of a tiger (1st group);
– long ears a hare (group 2);
- protective coloration in a grasshopper (3rd group);
- an elephant's trunk (4th group);
- thick fox fur (group 5).

Note: the set of tasks may be different - depending on the manuals available in the biology office (tables, illustrations, living plants or herbariums and stuffed animals).

On the blackboard, the teacher writes an algorithm according to which it is necessary to analyze the object.

Students work in groups: make notes in notebooks; prepare and then present their material (any student can be a delegate from the group). After each presentation, a collective discussion is organized.

At the final stage of the lesson, the "Business card report" technique is used: and conclusions are formulated and written down in the notebook, corresponding to the materials of this and the previous lessons, i.e. on the topic as a whole).

Business card report:

- a set of “ business cards»With surnames and first names;
- before the start of the lesson, all business cards are shuffled and placed in a pile on the teacher's table;
- the owner of the top card should speak at the end of the lesson with a summary on the topic of the lesson.

Until the end of the lesson, the speaker is not known, so the technique captivates the children with its playful side and assumed responsibility. Interest also increases if the teacher acts as a participant in this game and puts his business card in a common pile.

After the mini-report, a joint formulation of conclusions is carried out:

- any kind of living organisms is adapted to the conditions in which it lives;
- adaptation of organisms to the environment is manifested at all levels of organization - biochemical, cytological, histological, anatomical;
- physiological adaptations - an example of the reflection of the structural features of the organization in the given conditions of existence;
- taking care of the 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 physiological adaptations;
- any adaptations are relative and appropriate only in specific conditions of existence.

Thus, fitness is the relative expediency of the structure and functions of the organism, which is the result of natural selection, which eliminates individuals unadapted to these conditions of existence.

Homework

1. Analyze the following terms and write down the associations that arise in a notebook:

1st option - pre-adaptation;
2nd option - maladjustment.

2.

1st option - the presence of a shell in land turtles;
2nd option - constant growth of incisors in rodents.

Note: some classes have difficulty teamwork, so the lesson can be done in the form independent work with the tutorial, it will be useful to use the table "Occurrence of fixtures".

3. Explain how a striped coloration could have arisen in a tiger, long ears in a hare, and an elephant's trunk in terms of:

1st option - Linnaeus;
2nd option - Lamarck;
3rd option - the synthetic theory of evolution.

4. Explain the relativity of the following devices:

1st option - absence or underdevelopment of sense organs in cave animals;
2nd option - cactus leaves-needles;
Option 3 - a thick layer of fat in northern whales.

Methodology for working with mazes:

a maze consists of statements with which the student either agrees or disagrees;

depending on the decision, he moves through the maze according to the arrows, finding the correct answer or getting to a dead end;

after reaching the last statement, the student should receive a certain code - digital or, as in this case, alphabetic.

Note: with the correct execution of this labyrinth, the word "adaptation" is obtained, written in reverse order to exclude guessing ("eggsatpada").

The adaptability of an organism to its environment is of great importance in the process of survival of living things and is the result of natural selection.

The existence of an evolutionary fitness mechanism ensures maximum adaptation to the conditions in which the species lives.

Fitness - what is it

It consists in the correspondence of the structural features, physiological processes and behavior of a living organism to the environment in which it lives.

This mechanism increases the chances of survival, optimal nutrition, mating and raising healthy offspring. This is a universal feature common to all creatures on the planet from bacteria to higher forms life.

This adaptation mechanism manifests itself in a very diverse way. Plants, animals, fish, birds, insects and other representatives of flora and fauna are quite creative in the choice of means to help preserve their species.

The result is a change in color, body shape, organ structure, methods of reproduction and nutrition.

Traits of adaptability to the environment and their result

For example, the body of a frog merges with the color of water and grass and makes it invisible to predators. White hare changes color from gray to white in winter, which helps him to be invisible against the background of snow.

The chameleon is considered a champion in camouflage practice. But, alas, the opinion that it adjusts to the color of the place in which it is located somewhat simplifies the real picture. Changing the color of this amazing lizard is a response to the effects of air temperature, sun UV rays, and even depends on the mood.

And the ladybug, instead of disguising, uses a different strategy for choosing a color - scaring away. Its deep red color with black dots signals that this insect may be poisonous. This is not true, but what difference does it make if such a move helps to survive?

The woodpecker's head is an excellent example of the formation of a certain body shape, structure and functioning of organs. The bird has a powerful but resilient beak, a very long thin tongue and a shock absorption system that protects the brain from injury when the bird's beak hits the tree trunk.

A curious find is “aggression” in plants. Stinging nettle petals - great way protection from herbivores. The camel's thorn has changed the leaves and roots, thanks to which it successfully retains moisture in the desert. The way a sundew eats flies allows it to receive nutrients in a very uncharacteristic way for a plant.

Geographic speciation

It is also appropriate to use the term "allopatric" formation of species. It is associated with the expansion of the habitat, when the species occupies more and more territories. Or with the fact that the territory is divided by natural barriers - rivers, mountains, etc.

In such a situation, there is a collision with new conditions and new "neighbors" - species with which you need to learn to interact. Over time, this leads to the fact that, thanks to the ability to adapt, new beneficial traits are formed and genetically fixed in the species.

Representatives of geographically isolated populations do not interbreed with each other. As a result, they begin to possess a number of rather striking differences from their relatives. Thus, as a result of selection, the marsupial wolf and the wolf from the order of carnivores have diverged quite far in their features as a result of selection.

Ecological speciation

Not associated with direct expansion of the area. It occurs as a result of the fact that living conditions within the same area may differ.

So, among plants, an example can be species diversity dandelion, which differs across Eurasia.

The relative fitness of the cactus

The plant demonstrates amazing ability survival in the harshest drought conditions: waxy film and thorns minimize evaporation, well developed root system able to go deep into the soil and accumulate moisture, the needles protect against herbivores. But, in a situation of heavy downpours, the cactus dies from an excess of moisture due to rotting of the root system.

The relative fitness of the polar bear

In Latin, this bear is called Ursus maritima, which means sea bear. Its coat is well adapted to cold water.

It does not let water through during swimming and almost completely delays the transfer of heat from the skin of the animal. But if you put polar bear in more warm conditions habitat of his brown relatives, he will die from overheating.

The relative fitness of the mole

This animal lives mainly in the ground. It has a streamlined body, powerful spade-shaped limbs with developed claws. He is very dexterous in digging tunnels of many meters.

And at the same time he does not orient himself at all on the surface: his visual system is undeveloped, and he can only move by crawling.

The relative nature of the camel's fitness

The hump of a camel is its pride! Water, precious in drought conditions, accumulates there. Of course, not in the literal sense of water, these are H2O molecules associated with lipid, fat cells.

The animal can endure hunger for a long time, lie on the hot sand, sweating is minimized. It is not just that the nomads of the Sahara moved exactly on camels. But, alas, in snowy conditions, this hardy handsome man cannot cope with movement, nutrition and maintaining body temperature.

What characterizes the adaptability of plants to insect pollination

The flowers of plants are beautiful, unlike each other, you want to admire them! True, the biological significance of this beauty is not at all in pleasing a person.

the main task flowering plant- attract a pollinator insect. For this, several main ways are used: bright color of large flowers, a pleasant aroma for insects, crowding of small flowers in inflorescences and, of course, nutritious nectar inside the flower.

Conclusion on the adaptability of organisms to the environment

Identifying patterns and studying the adaptations of the animal world in different forms terrestrial, aquatic, aerial life is important and limitless interesting topic for researchers. Since it reveals the main ways of the evolutionary process of modification of living beings.