Possible path for the emergence of any device. Educational objectives: to promote students’ assimilation of knowledge about the mechanism of emergence and formation of devices (adaptations)
DEVELOPMENT OF A LESSON ON THE TOPIC
APPEARANCE ADAPTATION
Today we will talk to you about the adaptation of organisms to living conditions. Let's 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 conditions environment arise as a result of natural selection, so let's remember:
1. what is it natural selection?
Survival and reproduction of the fittest organisms.
2. What forms of natural selection do you know?
Moving, disruptive, stabilizing.
3. What is driving selection?
- a form of natural selection that operates under directed changes in conditions external environment.
4. Give an example of driving selection?
Dark color birch moth butterflies 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 the intermediate, average state of a trait.
6.Give an example.
Two races of the great rattle in hay meadows, polymorphism of 2 forms of ladybird flowers
7.What is stabilizing selection?
Stabilizing selection is a form of natural selection; individuals with characteristics that do not deviate from the norm are preserved.
8.Give an example
The average number of chicks in a nest, the optimal sizes and shapes of flowers and inflorescences in insect-pollinated plants.
Now we open our notebooks and write down the topic: “The emergence of devices.”
As a result of natural selection, plants and animals develop adaptations that are appropriate to the environment in which they are constantly found. It is known that birds have devices for flight - wings. Such adaptations to the conditions of existence have long attracted human attention. No wonder they say that “birds are given wings to fly.” TO aquatic environment The fish are perfectly adapted. 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 biological species, which ensures the possibility of its existence in certain environmental conditions. Typically adaptations are divided into general and specific.
General adaptations- These are adaptations to life in a wide area of environmental conditions. An example is the adaptation of vertebrate limbs to the terrestrial environment.
Particular adaptations are adaptations to a particular way of life. Examples include the ability of monkeys to climb trees, or the ability of sharks to swim.
Many examples of private adaptations are associated with the presence of so-called protective coloring in animals; it is conventionally divided into several types: camouflage, mimicry, and demonstration.
You will become more familiar with each type of protective coloring as you work with the text.
We divide into 3 groups, each group answers 4 questions that are in front of you. Write down the answers in your notebook. Each group representative then dictates their answers to the other groups, and the others write them down.
Now we will check how you have learned this topic, in front of you are illustrations - you need to name what form of protective coloring is presented in the illustration.
QUESTIONS
1. What is camouflage?
2.What types of camouflage exist?
3.Give an example of camouflage?
4. What is the significance of camouflage coloring?
DISGUISE
Camouflage is a device in which the body shape and color of animals merge with surrounding objects. There are several types of camouflage: cryptic coloring, dismembering, hiding. The cryptic coloration (CC) of an animal ensures that the individual resembles the surrounding background. Animals that live in grass are green in color (lizards, grasshoppers, caterpillars), while desert dwellers are yellow or brown (desert locust, long-eared roundhead, saiga). Disruptive, or dismembered, coloring is characterized by the presence of contrasting spots and stripes that disrupt 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 coloration, that is, spots in the animal’s coloration are in harmony with the background. Disruptive coloring is characteristic of many animals (locusts, butterflies, longhorned beetles, lizards, chipmunks, zebras). Concealing coloring is based on the countershadow effect: the most brightly illuminated areas of the body are colored darker than the less illuminated ones: in this case, the coloring seems more monotonous, and the outlines of the animal merge with the background. This coloration (“dark back - light belly”) is characteristic of most fish and other inhabitants of the water column, 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 type and form of mimicry?
4. What is the significance of mimicry?
MIMICRY
Mimicry is the similarity of a defenseless and edible animal species with one or more representatives of unrelated species. In nature, there are 2 types of mimicry: 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 imitate wasps. Textbook examples of mimesia are some seahorses; for example, the rag-horse resembles algae.
There are 2 forms of mimicry: Batesian, described by G. Bates, and Müllerian, described by F. Müller. An example of Batesian mimicry is the case of resemblance individual species white butterflies with inedible brightly colored and foul-smelling heliconid butterflies. In a variant of Müllerian mimicry, several protected species have external resemblance and coloration, for example some types of wasps.
There are many animals that use both defense mechanism sound imitation. Mostly this phenomenon found among birds. For example, a rabbit owl, living in rodent burrows, can imitate the hissing of a snake.
Mimicry in plants serves to repel or attract animals. For example, the nectar-less flowers of the bellozor are similar to honey-bearing 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 demonstration?
2. Give examples of threatening colors or shapes?
3.Give examples of warning colors or shapes?
4. What is the importance of demonstration?
DEMONSTRATION
Display - the shape or color of animals that makes them noticeable against the background of the environment. There are two types of demonstration: threatening and protective form or color. Menacing coloring is very different from the background of the environment, is demonstrated suddenly in case of danger and is usually combined with threatening pose and sounds. For example, some species of butterflies (from the genera of hawk moths, ribbon moths), cicadas, locusts, mantises, etc. have ocellated spots or bright bands on the hind wings. Warning coloration, a type of protective coloration and form in which inedible animals have a bright, usually variegated, color. Such animals are clearly visible due to contrasting color combinations (black, red, white; orange, white, black, etc.). Among vertebrates, warning coloration is characteristic of some fish, salamanders, and toads.
Row poisonous snakes notifies of its presence not so much by color as by sounds, mainly of a so-called instrumental nature, i.e. produced either by friction of scales, or by means of a special “rattle” at the end of the tail (rattlesnakes).
The display ensures that the animals are visible, which is an advantage because, once recognized, they are not attacked by predators.
According to the teachingCharles DarwinUnder conditions of natural selection, the fittest survives. Consequently, it is selection that is the main reason for the emergence of various adaptations of living organisms to their environment. Let us show this using the example of the formation of adaptations in grouse birds to life in lower tier forests. To do this, let us recall some features of the external structure and lifestyle of these birds: a short beak, which allows them to peck berries and seeds from the forest floor, and in winter from the surface of the snow; horny fringes on the fingers provide walking on the snow, the ability to escape the cold by burying yourself in the snow at night; short, wide wings, making it possible to take off quickly and almost vertically from the ground.
Let us assume that the adaptations described above were not developed in the ancestors of grouse birds. However, when their habitat changed (due to cold weather or due to some other circumstances), they were forced to winter in the forest, nesting and feeding on the forest floor.
The continuous process of the emergence of new mutations, their combination during crossing, and waves of numbers 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 whose external structural features were more consistent with their habitat conditions. In the process of natural selection, it was these birds that left fertile offspring and their numbers 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. Those with these traits were again more likely to survive and leave offspring. And so, from generation to generation, based on the strengthening and accumulation of useful hereditary changes, the adaptability of grouse birds to life in the lower tier of the forest was improved.
Charles Darwin's explanation of the emergence of fitness is fundamentally different from the understanding of this processJean Baptiste Lamarck, who put forward the idea of the innate ability of organisms to change under the influence of the environment only in a direction beneficial to them. Everyone has famous hedgehogs sharp spines 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 an adaptation: even a slight coarsening of hair could have helped the hedgehog’s distant ancestors survive. Gradually, over millions of generations, only those individuals survived that happened to have more and more developed spines. It was they who managed to leave offspring and pass on their hereditary characteristics to them. The Madagascan “bristle hedgehogs” - tenrecs and some spiny-haired species of mice and hamsters - followed the same path of the appearance of needles instead of hair.
Considering other examples of adaptation in living nature (the appearance of spines in plants, various hooks, hooks, and flies in plant seeds due to their dispersal by animals), we can assume that the mechanism of their occurrence is common: in all cases, adaptations do not appear immediately in a ready-made form as something given, but are formed over a long period of time in the process of evolution through the selection of individuals who have the trait in the most pronounced form.
6. The emergence of devices. Relative adaptability.
Adaptation is the harmony of the organism with its environment (in in a broad sense). Adaptation is a special morphophysiological property that can ensure the survival and reproduction of organisms in a concert environment (in the narrow sense). Adaptation group - means passive protection- these are such wasps, by their very presence alone, that determine the greater likelihood of survival of individuals in the struggle for existence. a) hard protective covers; b) the ability to curl into a ball (centipede, armadillo); c) needles and spines; d) burning hairs in plants, stinging cells in animals; e) adaptive coloration and structure (shape) of the body - protective coloration (seasonal coloration (partridge)); dismembering coloring (tiger); countershade (fish); brightly colored individuals (warning coloration); mimicry - imitative coloring and behavior, camouflage, resemblance to inedible objects; f) complex adaptations (arising through minor hereditary deviations) insectivory in plants, symbiosis.
The adaptability of organizations is the result of the action of the driving forces of evolution in the given conditions of existence. Any adaptation helps org-mothers to survive only in those conditions in which it was formed under the influence driving forces evolution. In these conditions, it is relative (on a bright day in winter, a white partridge reveals itself as a shadow in the snow. A white hare, invisible in the snow in the forest, visible against the background of dark trunks.). Orgs have unnecessary organs and signs. All these many and other factors say that fitness is not absolute, but relative.
7. Microevolution. Speciation. Results of evolution.
Microevolution is evolutionary processes occurring within a species and leading to new, intraspecific groups: populations and subspecies. A population is an elementary evolutionary structure. Subspecies is a group of populations of a given species that are morphophysiologically different from all other populations within the species. Mutation is an elementary, evolutionary material.
An elementary evolutionary phenomenon is a change in the gene pool of a population. The gene pool is the totality of genotypes of all individuals in a population. Genotype is the totality of genes of an individual. The elementary evolutionary factor directing the evolutionary process is natural selection.
The formation of new species in nature occurs under the influence of the driving forces of evolution. When the conditions of existence within a species change, a process of divergence of signs of divergence occurs, which leads to the formation of new groups, individuals within the species. Initial stages evolutionary process, occur within the species and lead to the formation of new intraspecific groups - populations of subspecies (this process is called microevolution). Geographic speciation is associated with the expansion of the range of the original species or with its division into isolated parts - physical barriers (rivers, lakes, mountains, climate...). Ecological speciation occurs in cases where populations of one species remain within the same area, but their living conditions are different (their genetic composition changes).
Results of evolution. Evolution has 3 closely related important consequences:
1) Gradual complication and increase in the organization of living beings.
2) The relative adaptability of organisms to environmental conditions.
3) Variety of types.
Type criteria: 1.Morphological criterion - similarity of external and internal structure. 2. Ecological criterion - plants have different places of growth. 3.Geographical criterion - area. 4. Physiological criterion: the impossibility of crossing species is the main meaning. They are limited by their physiological capabilities. 5.Genetic complex - determines the entire essence of the species (set of chromosomes). It does not play a huge role, i.e. it is indistinguishable from sight.
8. Evidence of evolution organic world.
Macroevolution is the process of creating new genera from species, new families from genera, etc. It occurs over large periods of time and is not accessible to direct study. The same processes operate in macroevolution - natural selection and associated extinction, the struggle for existence. Macroevolution has a divergent character, just like microevolution.
Embryological documents.
Charles Darwin also noted that there are relationships between individual development organizations and their evolutionary development. These connections were then studied in detail by other scientists. Similarity of embryos. Very similar internal organization embryos of fish, rabbit, lizard and man: all first have a notochord, then a spine of cartilaginous vertebrae, circulatory system with one circle cut. As subsequent development progresses, the similarity between embryos weakens. All of the above speaks about the origin of all chordates from one trunk, which split into many branches in the course of evolution. Biogenetic law. German scientists established the law of correlation of ontogenesis. According to him, each individual in ontogenesis is a brief repetition of phylogeny (the history of the development of its species). For example, the tadpoles of tailless amphibians develop a tail - a repetition of the characteristics of their tailed ancestors.
Paleontological documents.
Paleontology studies the fossil remains of extinct organisms and reveals their similarities and differences with modern organisms. Paleontologists based on fossil remains will recover appearance and the history of extinct organisms, learn about the plant and animal world of the past. Paleontological findings speak of connections between various systematic groups. In some rows they were able to establish transitional forms, in others - phylogenetic series (series of species that successively replace one another). Fossil transitional forms. A group of animal-toothed reptiles was found. They combine the characteristics of reptiles and mammals. Such organisms are classified as transitional forms. Animal-toothed reptiles are similar to mammals in the structure of the skull, limbs and vertebrae, as well as in the division of teeth into molars, incisors and fangs. Archeopteryx is an animal the size of a dove and had the characteristics of a bird, but also retained the features of reptiles. The signs of birds were obvious: the resemblance of the hind limbs to the tarsus, the presence of feathers. Signs of a premise: abdominal ribs, caudal vertebrae and the presence of teeth. Ar-ks could hardly fly well, because... he has a sternum without a keel, weak pectoral muscles and wing muscles. Phylogenetic series. Paleontologists managed to reconstruct the phylogenetic series of animals. An example is the evolution of the horse. Her largest ancestor was the size of a fox, her limbs were four-fingered, etc. , moved in leaps and bounds. But then living conditions changed for the worse and he could now only escape from enemies by running fast. In the process of struggling for existence, his legs lengthened and the number of fingers reaching the ground decreased, his spine strengthened, which made it possible to run quickly, etc.
The system of plants and animals is a reflection of evolution.
The evolution of life on earth is carried out by micro- and macro-evolutionary processes in their unity. Now organisms are divided into groups using systematic categories: type (division - for plants), class, order (order for plants), family, genus, species. For extensive systematic groups, intermediate categories are added: under types, under classes, etc. The multiplicity of systematic categories is caused by the extraordinary diversity of species and the desire of scientists to provide such a system, which would reflect family ties between groups of organisms. Each highest systematic group, starting from the genus, unites groups that are lower in rank and have a common ancestor. The genus unites species that descended from one ancestor and turned out to be, and have turned out to be, as a result of the struggle for existence and natural selection, capable of existing and successfully reproducing in different geographies and conditions. Evolution has 3 closely related important consequences: 1. Gradual complication and increased organization of living beings. 2. Relative adaptability of organisms in the external environment. 3. Variety of types.
The adaptation of an organism to its environment plays a role great value in the process of survival of living beings 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.
Adaptability - 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 characteristic of all creatures on the planet from bacteria to higher forms life.
This adaptation mechanism manifests itself in a very diverse manner. Plants, animals, fish, birds, insects and other representatives of flora and fauna are quite inventive in choosing means to help preserve their species.
The result is a change in color, body shape, organ structure, methods of reproduction and nutrition.
Traits of adaptation to the environment and their results
For example, the frog's body blends with the color of water and grass and makes it invisible to predators. The 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 the champion in camouflage practice. But, alas, the idea that it adapts 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, solar UV rays, and even depends on mood.
A ladybug Instead of camouflage, it uses another color selection strategy - scaring. Its rich red color with black dots gives a signal that this insect may be poisonous. This is not true, but what difference does it make if such a move helps you survive?
The woodpecker's head is an excellent example of the formation a certain shape body, structure and functioning of organs. The bird has a powerful but elastic beak, a very long thin tongue and a shock absorption system that protects the brain from injury when the bird’s beak hits a tree trunk with strong force.
An interesting finding is “aggression” in plants. Stinging nettle petals - great way protection from herbivores. Camel-thorn modified leaves and roots, thanks to which it successfully retains moisture in desert conditions. The feeding method of the sundew, which eats flies, allows it to obtain 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 all large areas. Or with the fact that the territory is divided by natural barriers - rivers, mountains, etc.
In such a situation, a collision occurs with new conditions and new “neighbors” - species with which one must learn to interact. Over time, this leads to the fact that, thanks to the ability to adapt, the species begins to form and genetically consolidate new advantageous traits.
Representatives of geographically isolated populations do not interbreed. As a result, they begin to have a number of quite striking differences from their relatives. So, marsupial wolf and the wolf from the order of carnivores, as a result of selection, diverged quite widely in their features.
Ecological speciation
Not associated with direct expansion of range. It occurs as a result of the fact that within the same habitat, living conditions may vary.
Thus, among plants an example would be species diversity dandelion, which varies across Eurasia.
Relative nature of cactus fitness
The plant demonstrates amazing ability survival in the harshest drought conditions: waxy film and spines minimize evaporation, well developed root system is able to go deep into the soil and accumulate moisture; the needles protect against herbivores. But, in a situation of torrential downpours, the cactus dies from excess moisture due to rotting of the root system.
Relative fitness patterns of the polar bear
In Latin this bear is called Ursus maritima, which means sea bear. Its coat is perfectly adapted to cold water.
It does not allow water to pass through during swimming and almost completely blocks the transfer of heat from the animal’s skin. But if you put polar bear in the warmer living conditions of its brown relatives, it will die from overheating.
Relative nature of mole fitness
This animal lives mainly in the ground. It has streamlined shape bodies, powerful spade-shaped limbs with developed claws. He very skillfully digs multi-meter tunnels.
And at the same time, he is not at all oriented on the surface: his visual system is undeveloped, and he can only move by crawling.
Relative nature of camel fitness
The camel's hump is its pride! Precious water accumulates there in drought conditions. Of course, not in the literal sense, water is H2O molecules associated with lipid and fat cells.
An animal can endure hunger for a long time, lie on hot sand, and sweating is minimized. It was not for nothing that the nomads of the Sahara rode camels. But, alas, in snowy conditions this hardy beauty cannot cope with movement, nutrition and maintaining body temperature.
What characterizes the adaptability of plants to pollination by insects?
The flowers of the plants are beautiful, different from each other, you want to admire them! Is it true, biological significance This beauty is not at all about pleasing a person.
The main task of a flowering plant is to attract pollinating insects. Several main ways are used for this: the bright color of large flowers, a pleasant aroma for insects, crowding of small flowers into inflorescences and, of course, nutritious nectar inside the flower.
Conclusion about the adaptability of organisms to their environment
Identification of patterns and study of adaptations of the animal world in various forms land, water, air life is important and limitless interesting topic for researchers. Because it reveals the main paths of the evolutionary process of modification of living beings.
Relative character fitness
Development of organs for capturing, holding, killing prey (tentacles).
Masking coloring.
Release of paralyzing poisons.
Output special ways behavior (waiting in ambush).
The mechanism of occurrence of adaptations
According to the teachings of Charles Darwin, natural selection is the survival of the fittest. Consequently, it is selection that is the main reason for the emergence of various adaptations of living organisms to their environment. The explanation of the emergence of fitness given by Charles Darwin is fundamentally different from the understanding of this process by Jean Baptiste Lamarck, who put forward the idea of the innate ability of organisms to change under the influence of the environment only in a direction that is beneficial for them. All known octopuses have changing colors that reliably protect them from most predators. It is difficult to imagine that the formation of such changing colors is caused by the direct influence of the environment. Only the action of natural selection can explain the emergence of such an adaptation: even simple camouflage could have helped the distant ancestors of the octopus survive. Gradually, over millions of generations, only those individuals remained alive that accidentally turned out to have more and more developed coloration. It was they who managed to leave offspring and pass on their hereditary characteristics to them.
Corresponding to a specific habitat, adaptations lose their significance when it changes. The following facts can be evidence of the relative nature of fitness:
protective devices against some enemies are ineffective against others;
the manifestation of instincts in animals may be inappropriate;
an organ that is useful in one environment becomes useless and even relatively harmful in another environment;
More advanced adaptations to a given habitat are also possible.
Some species of animals and plants multiplied quickly and spread widely in completely new areas globe, where they were accidentally or intentionally introduced by humans.
Thus, the relative nature of fitness contradicts the statement of absolute expediency in living nature.
Adaptations such as protective coloration arose through the gradual selection of all those small deviations in body shape, in the distribution of certain pigments, in innate behavior that existed in the populations of the ancestors of these animals. One of the most important characteristics Natural selection is its cumulativeness - its ability to accumulate and strengthen these deviations over a series of generations, composing changes in individual genes and the systems of organisms controlled by them.
Natural selection picks up all those minute changes that increase the similarity in color and shape with the substrate, the similarity between edible form and so inedible form which he imitates. It should be taken into account that different types predators enjoy different methods search for prey. Some pay attention to shape, others to color, some have color vision, others do not. Therefore, natural selection automatically enhances, as far as possible, the similarity between the imitator and the model and leads to those amazing adaptations that we observe in nature.