n Various One of the most important ciliate stages in the evolution of the animal world was the transition of single-celled protozoa to a colonial lifestyle. All multicellular animals originate from colonial flagellates. flagellar sarcodae
Multicellular animals n From colonial unicellular animals, the Sponge type first arose, then the Coelenterate type (two-layer multicellular animals, consisting of two layers of cells (ectoderm and endoderm)
Coelenterates n The body of coelenterates also consists of two layers of cells. The outer layer is called ectoderm, and the inner layer is called endoderm. Between them there is a gelatinous structureless substance - mesoglea. 1 - siphonophore, 2 sea anemone, 3 - coral polyps, 4 - scyphoid jellyfish.
n n n The further history of the animal world goes in two different directions: the family tree is divided into two large trunks - protostomes and deuterostomes. In protostomes, the opening leading to the gastrula (primary mouth) turns into an oral opening, and in deuterostomes, into an anal; their mouth opening later forms anew, at the opposite end of the embryo. Let's follow up future fate each of these directions of evolution of the animal world.
The trunk of protostomes forms a series of branches, with a gradual complication of the organism. n n n The lowest branch are Flatworms. They develop bilateral symmetry and for the first time among multicellular organisms special excretory organs Nearby there is another branch of worms - the Roundworms type
n Annelids have the highest organization among worms; they have all the organ systems inherent in higher types of animals: a tubular intestine, a circulatory system, organs of excretion, movement, respiration, a nerve chain, a secondary body cavity, and the division of the body into segments appears
The complication of the body cavity can be traced in various worms n flatworms the body cavity is filled with parenchyma. In roundworms the primary is formed, and in annelids secondary body cavity.
n Mollusks are very close in origin to annelids. Their embryonic development proceeds in the same way. A characteristic feature of mollusks is a protective cover in the form of a shell covering the body.
Increasing complexity of animals in the process of evolution n An important evolutionary change is the complication of the nervous system. staircase nervous system flatworms is replaced by a ventral nerve cord in annelids and a scattered nodule in mollusks.
n n n Annelids gave rise to the phylum Arthropods, which have the highest organization among invertebrate animals ( exoskeleton, differentiation of muscles, formation of articulated limbs, complex mouth parts, division of the body into the head, chest and abdomen, complication of the respiratory system, nervous system, and sensory organs. Classes of Arthropods: The now extinct class of trilobites, crustaceans, arachnids, centipedes and insects. It is important to note that arthropods developed in two directions: trilobites and crustaceans are adapted to life in water (gill-breathing), while others are tracheal-breathing land animals.
Deuterostome trunk n n n This trunk of the animal kingdom in turn divided into two large branches. One of them formed the type Echinodermata. The second, more significant branch of deuterostomes formed the phylum Chordata.
Phylum Echinodermata n n These are exclusively marine animals with radial or radial symmetry of the body. They are characterized by the presence of a calcareous skeleton that develops in the connective layer of the skin.
Phylum Chordata n n One of the most primitive branches of chordates is the subphylum Lancelet. By the structure of the lancelet one can judge the distant ancestors of all chordates.
n n The most ancient representatives of the primary chordates gave rise not only to the skullless, but also to the primary cranial ones, from which the type Cranial or Vertebrates originated. First, the lowest branch of vertebrates was formed - jawless vertebrates (representative - extinct ostracoderms from the Silurian period.
Class Cyclostomes n Close to jawless modern class Cyclostomata, which include lampreys and hagfish. n. . New folder (2) lamprey. jpg
n n n Further evolutionary development of vertebrates is associated with the emergence of the jaw apparatus, which made it possible to intensify the process of food capture and thus significantly increase metabolism and all other life processes. The first gnathostomes were fish. In the class of fishes formed, not counting extinct armored fish, two main branches: cartilaginous fishes and bony fishes
Cartilaginous fish n K cartilaginous fish include sharks, rays and chimeras 1 - stingray, 2 manta rays, 3 - electric ray.
Bone fish n n Bone fish are diverse: 1 - beluga, 2 - Atlantic sturgeon, 3 sea sturgeon and stellate sturgeon. freshwater forms. These include: sturgeon, ray-finned, lungfish and lobe-finned fish, flounder, lionfish, tuna, sea bass
Lobe-finned fish n n Ancient representatives of lobe-finned fish gave rise to the first amphibians - stagocephalus, which began to colonize land from the end of the Devonian period. This direction of evolution was possible because lobe-finned fish had a certain skeletal structure of fins that formed five-fingered limbs, lung sacs, which made the transition to air breathing possible. The structure of the hand of an amphibian and lobe-finned fish
Class amphibians, or amphibians Representatives of the order of tailless amphibians n Stegocephalians gave rise to various modern orders of tailed, tailless and legless amphibians. Representatives of the order of tailed amphibians
Class reptiles n From the ancient stegocephalians, in addition to amphibians, reptiles, or reptiles, also arose, which are true terrestrial vertebrates.
The order of the first bird, or Archeopteryx n Birds and mammals evolved from reptiles. An intermediate link between birds and ancient reptiles are the first birds (Archaeopteryx), who lived in the Jurassic period.
n An intermediate link between reptiles and mammals were common in the Permian and Triassic periods animal-like reptiles - beast-lizards.
Class mammals: subclass oviparous n Mammals in the Jurassic and Cretaceous periods were represented by several branches, in particular – proto-beasts or oviparous ones.
Class mammals: subclass marsupials n One of the branches of mammals gave rise to lower animals, or marsupials, and higher animals, or placentals. Opossum, wombat, koala, marsupial devil, giant red kangaroo
Class mammals: subclass placental or higher animals n During the tertiary and Quaternary periods were formed modern units higher animals: insectivores, chiropterans, rodents, carnivores, mammoth, woolly rhinoceros, saber-toothed cetaceans, tiger, peat deer, cave bear, ungulates, primates.
Order Homo sapiens n About a million years ago from great apes man emerged and the prehistoric period of human development began.
Any species of animal appears, spreads, conquering new territories and habitats, and lives for some time in relatively constant conditions of existence. When these conditions change, it can adapt to them, change and give rise to a new species (or new species), or it may disappear. The totality of such processes constitutes evolution organic world, historical development of organisms - phylogeny.
This essay is devoted to the topic “Development of the animal world.” In order to expand on the topic, the following questions are covered:
1. The reasons for the evolution of the animal world based on the ideas of Charles Darwin
2. Complication of the structure of animals. Diversity of species as a result of evolution.
3. Evidence of animal evolution.
Causes different levels animal organizations, differences today existing species from the extinct, manifestations of atavisms have long been of interest to scientists and church ministers.
The famous English scientist Charles Darwin (1809-1882) explained these phenomena most fully in his work “The Origin of Species”.
According to Darwin's teaching, the diversity of species was not created by God, but was formed due to constantly occurring hereditary changes and natural selection. In the process of survival of the fittest individuals, Darwin noted the presence of a struggle for existence, the result of which is the extinction of unadapted organisms and the reproduction of the most fit.
Heredity is the ability of organisms to transmit to their descendants their specific and individual characteristics or properties. Thus, a certain species of animal produces offspring that are similar to their parents. Some individual characteristics of animals can also be hereditary, for example, coat color and milk fat content in mammals.
Variation is the ability of organisms to exist in various forms, responding to environmental influences. Variability manifests itself in individual characteristics every organism. In nature, there are no two absolutely identical animals. The born cubs differ from each of their parents in coloring, height, behavior and other characteristics. Differences in animals, as C. Darwin noted, depend on the following reasons: on the quantity and quality of food consumed, on fluctuations in temperature and humidity, on the heredity of the organism itself. Charles Darwin identified two main forms of variability that influence the evolution of the animal world - definite, non-hereditary, and indefinite, or hereditary.
By certain variability, Charles Darwin understood the occurrence of identical changes in a number of related animals under the influence of identical environmental conditions. Thus, the thick fur of Transbaikal squirrels changed to sparse fur during their acclimatization in coniferous forests Caucasus. Keeping rabbits in conditions low temperatures leads to the thickness of their fur. Lack of food leads to stunted growth of wild and domestic animals. Consequently, a certain variability is a direct adaptation of animals to changed environmental conditions. Such variability is not passed on to descendants.
By uncertain hereditary variability, Charles Darwin understood the occurrence of various changes in a number of related animals under the influence of the same (similar) conditions. Indefinite variability, according to Charles Darwin, is hereditary and individual, since it arises by chance in one individual of the species and is inherited. An example of individual hereditary variability is the appearance of sheep with short legs, the absence of pigment in the feathers of birds or in the fur of mammals.
Charles Darwin considered one of the reasons for the evolution of the animal world to be the struggle for existence, which arises due to the intensive reproduction of organisms. A parent pair of any animal species produces numerous offspring. Out of the number of offspring born, only a few will survive to adulthood. Many will be eaten or die almost immediately after birth. Those who remain will begin to compete with each other for food, best places habitat, shelter from enemies. The descendants of those parents who are most adapted to the given living conditions will survive. Thus, the struggle for existence leads to natural selection - the survival of the fittest.
In nature, individuals of the same species differ from each other in many ways. Some of them may be useful, and, as Darwin noted, “individuals having even a slight advantage over the rest will have best opportunity survive and leave the same offspring.” The process occurring in nature that preserves organisms most adapted to environmental conditions and destroys those that are not adapted is called natural selection. According to Charles Darwin, natural selection is the main, leading cause of the evolution of the animal world.
2. INCREASING COMPLEXITY OF THE STRUCTURE OF ANIMALS. DIVERSITY OF SPECIES AS A RESULT OF EVOLUTION
Thus, birds have a streamlined body, a lightweight skeleton, which facilitates rapid movement in the air with the help of wings. Aquatic animals such as whales, dolphins, seals, have a torpedo-shaped body, adapted for rapid movement in the aquatic environment. Land animals have well-developed limbs for moving quickly on the ground. Underground animals, such as moles and mole voles, lead a burrowing lifestyle. Small animals are covered with short thick hair, which prevents particles of earth from getting on the skin, and have powerful forelimbs adapted for digging underground passages.
The existing vertebrates - fish, amphibians, reptiles, birds and mammals, characterized by a progressively more complex organization, arose on the basis of hereditary variability, the struggle for existence and natural selection during a long historical development.
Surrounding us animal world not only rich a large number individuals, but also the diversity of species. Each individual of any species is adapted to life in the conditions of its habitat. If large group Representatives of any species find themselves in different conditions or they switch to feeding on different foods, this may lead to the appearance of new characteristics or adaptations. If these new adaptations, under different conditions, turn out to be useful for the migrated animals, then, thanks to natural selection, the newly acquired characteristics will be preserved in their ranks and will be passed on from generation to generation. Thus, in the process of evolution, several new ones can be formed from one species. The process of divergence of characters in related organisms was called divergence by Charles Darwin.
An example of divergence is the small birds finches on the Galapagos archipelago. Darwinian species of finches differ in the shape and size of their beaks (Fig. 194). Darwin found that finches, which had a small sharp beak, fed on larvae and adult insects. Finches with a powerful massive beak fed on tree fruits. Gradual transitions in the variability of these beaks in finches were also noted. Thus, in the process of evolution, due to the divergence of characters determined by the direction of natural selection, speciation occurred. The emergence of a new species, as Darwin noted, is preceded by the formation of intermediate forms - varieties. Ends like this evolutionary process the formation of new species.
Through divergence and the directed action of natural selection, a variety of species is formed in nature.
2. Evidence of animal evolution
Paleontological evidence
Paleontology is the science of ancient organisms of past geological eras. She studies the fossil remains of those who lived on Earth tens and hundreds of millions of years ago. Fossil remains are fossilized shells of mollusks, teeth and scales of fish, egg shells, skeletons and other solid parts of organisms, prints and traces of their vital activity, preserved in soft silt, clay, sandstone (Fig.). These rocks once hardened and were preserved in a petrified state in various layers of the Earth. Using fossilized finds, paleontologists recreate the animal world of past eras. The study of paleontological samples that have reached us from the deepest layers of the Earth convincingly shows that the animal world of ancient times was significantly different from the modern one. The fossilized remains of animals located in shallower layers, on the contrary, bear structural features similar to modern animals. By comparing animals that lived in different eras, it has been established that the animal world has constantly changed over time. The relationship of modern animals from various systematic groups with extinct ones is established by the findings of so-called intermediate, or transitional, forms. For example, it became known that birds descended from reptiles, which are their closest relatives, but at the same time differ significantly from them.
In Europe, an animal print was found with characteristics that are characteristic of both reptiles and birds. The scientific name of the reconstructed animal is Archeopteryx. Features characteristic of reptiles are a heavy skeleton, powerful teeth (in modern birds they are missing), a long tail. Features characteristic of birds are wings covered with feathers. Using fossilized remains, scientists have fairly fully restored many transitional forms from distant ancestors to more modern animals.
Complete reconstruction of the appearance of organisms, transitional from distant ancestors to modern animals, serves as one of the paleontological evidence of the true picture of the evolution of living organisms on Earth.
Many animals that lived before have no analogues in the modern animal world - they are extinct. Today paleontologists are trying to unravel the reasons why they disappeared. The largest extinct animals were dinosaurs.
Embryological evidence
Feature Comparison embryonic development representatives various groups vertebrates, such as fish, newts, turtles, birds, rabbits, pigs and humans, showed that all embryos in the early stages of development are very similar to each other. The subsequent development of embryos retains similarity only in closely related groups, for example, in a rabbit, a dog, a person, who have a common structural plan in adulthood. Further development leads to the disappearance of similarities between the embryos.
Each representative of a species has only its own characteristics. character traits buildings. At the end of embryonic development, signs characteristic of a particular animal species appear.
Studying the successive stages of development of each embryo makes it possible to reconstruct the appearance of a distant ancestor. For example, the early stages of development of mammalian embryos are similar to fish embryos: they have gill slits. Apparently, the distant ancestors of animals were fish. In the next stage of development, the mammalian embryo is similar to the newt embryo. Consequently, among their ancestors there were also amphibians (Fig. 1).
Thus, the study of the embryonic development of various groups of vertebrate animals shows the relationship of the organisms being compared, clarifies the path of their historical development and serves as evidence in favor of the existence of the evolution of living organisms.
Comparative anatomical evidence
Comparing vertebrates of different classes, it was found that they all have a single structure plan. The bodies of amphibians, reptiles, birds and mammals consist of a head, trunk, anterior and hind limbs. They were characterized by similar skin eternities and were quadrupeds. Organs that have lost their function as a result of their long-term non-use are called vestigial. The presence of vestigial organs in animals is irrefutable evidence of the existence of evolution.
STAGE I
STAGE II
Fish Salamander Turtle Rat Human
Rice. 1 Similarity of vertebrate embryos
Rice. 2. Vestigial animal organs
If the process of embryonic development is disrupted for any reason, certain features of the animal's body structure may differ sharply from other individuals of the same species. However, their presence and similarity with other representatives of this class of animals indicates the related origin and evolution of each species. Cases of manifestation of ancestral characteristics in modern individuals are called atavism. Examples of it include: three-toedness in modern horses; additional pairs of mammary glands in those who always had one pair; Availability hairline all over the body.
Comparative anatomical series showing the directions of historical development in species belonging to the same class, family, or genus are considered significant evidence of evolution. For example, the methods of reproduction in oviparous, marsupials and placentals show the directions of development of reproductive systems; limbs of equids show the emergence of a one-toed foot in connection with changed living conditions, etc.
CONCLUSION
Thus, we have examined the basic principles of the development of the animal world based on the theory of Charles Darwin, according to which the diversity of species was formed due to constantly occurring hereditary changes and natural selection. One of the reasons for the evolution of the animal world according to Darwin is the struggle for existence, as a result of which the extinction of unadapted organisms occurs and the reproduction of the most adapted.
The amazing diversity of forms and body structures of animals is the result of natural selection, as a result of which there is a constant accumulation in descendants of characteristics that are useful to them in given conditions of existence, and this process, in turn, leads to a complication of the structure of animals. Moreover, in the process of evolution, several new ones can be formed from one species. The process of divergence of characters in related organisms was called divergence by Charles Darwin.
The diversity of extinct reptiles serves as an example of their divergence based on different living conditions.
Animals of the same species living on large territory, are usually heterogeneous. Their study shows the divergence of characters in individuals and the beginning of the formation of new systematic groups.
Literature
Akimov O. S. Natural science. M.: UNITY-DANA, 2001.
Gorelov A. A. Concepts of modern natural science. - M.: Center, 2002.
Gorokhov V.G. Concepts of modern natural science. - M.: INFRA-M, 2000.
Dubnischeva T.Ya. and others. Modern natural science. - M.: Marketing, 2000.
Basic concepts of modern natural science. - M. : Aspect - Pr, 2001
Petrosova R.A. Natural science and basic ecology. - M.: Academy, 2000.
Tchaikovsky Yu.V. Elements of evolutionary diagnostics. - M., 1999.
Natural selection as a guiding factor determines the path of evolution. The Russian evolutionist scientist A.N. Severtsov established the following evolutionary paths: aromorphosis, idioadaptation, degeneration.
Aromorphoses (from the Greek airo - to raise, raise and morphe - form) represent major evolutionary changes that lead to a general rise in the level of organization. Scientists include the emergence of photosynthesis, the appearance of multicellular organisms, sexual reproduction, a four-chambered heart in birds and mammals, and flowers and fruits in angiosperms as aromorphoses.
Let's get acquainted with the complication of the heart of vertebrates in the process of evolution.
Fish have a two-chambered heart. Venous blood enters the atrium, then into the ventricle, from which it goes into the aorta and then into the branchial vessels. Here the blood is enriched with oxygen and distributed to all organs of the body.
In amphibians, the atrium during evolution was divided into two halves - in the right half there is venous blood, and in the left half there is arterial blood. Blood enters the ventricle from both atria and mixes. In most reptiles, further complication of the heart occurs, and incomplete septum in the ventricle. In the left half of the heart the blood is almost entirely arterial, and in the right half it is venous.
In birds and mammals, complete septa have formed in the atrium and ventricle, so arterial blood does not mix with 1000 enous blood. As a result, arterial, oxygen-rich blood enters all organs of the body, which increases the metabolic rate, releases more energy, and warm-bloodedness occurs.
Idioadaptation (from the Greek idios - peculiar and from the Latin adaptape - to adapt) are minor evolutionary changes due to which organisms become adapted to certain environmental conditions, but there is no general rise in the level of organization.
Idioadaptations include, for example, changes in the beak of birds of different species of the same genus, associated with the type of food and the method of obtaining it.
Other examples of idioadaptation are all types of coloration in animals, the streamlined body shape of a number of aquatic animals, Various types limbs in insects and mammals.
Adaptations to pollination of flowers by wind and insects, modifications of leaves are examples of idioadaptations in plants.
* The powerful development of the body and individual organs in animals can be considered as special case idioadaptations For example, extinct saber-toothed cats had fangs that were 15 cm long, which allowed them to hunt large, thick-skinned mammals.
Aromorphoses, idioadaptations, and degenerations are closely related. Large systematic groups arise through aromorphoses. Idioadaptations and degeneration determine the emergence of smaller systematic groups.
Each large systematic group of organisms arises through aromorphosis. Its further evolution follows the path of idioadaptations or degeneration. Individuals of a large group inhabit different habitats, and they begin to develop adaptations to specific environmental conditions. Within a large group, smaller systematic groups arise.
The phylum chordates include bilaterally symmetrical animals with an internal skeleton, which is represented by the axial rod - chord. Lower chordates– lancelet, lamprey, hagfish (subtype skullless class lancelets (lancelet), subtype cranial or vertebrate class cyclostomes (lamprey, hagfish) have a notochord in the form of an elastic elastic cord located on the dorsal side of the bodies from the head to the tail. Higher chordates– fish, amphibians, reptiles, birds, mammals (including humans) have a notochord in the embryonic state. As these organisms grow and develop, it is replaced by a cartilaginous or bony spine. The notochord or spine is the support for muscle attachment.
Why are lancelets interesting, and why is it worth starting to talk about them when we touch on the issue of evolution? The structure of lancelets is like a diagram of the structure of all chordates. Overall plan their buildings include everything characteristic features this type:
→presence of chord
→gill slits piercing the pharynx
→nervous system in the form of a neural tube; the notochord is located between the neural tube and the intestine
→the circulatory system of chordates is closed, the heart is located above the chord.
Now let’s move on to the transformations that occurred in the chordate type over the course of evolution:
1. The first higher chordates. Cartilaginous and bony fish. The ancestors of chordates are bilaterally symmetrical animals similar to annelids. Active lifestyle of the first chordates. The origin of two groups of animals from them: sedentary (including the ancestors of modern lancelets) and free-swimming ones, with a well-developed spine, brain and sense organs. Origin from ancient free-swimming chordate ancestors of cartilaginous and bony fish.
2. More high level organization of bony fish compared to cartilaginous fish: the presence of a swim bladder, a lighter and stronger skeleton, gill covers, a more advanced method of respiration, which allowed bony fish to spread widely in fresh water bodies, seas and oceans.
3. Origin ancient amphibians. One of the groups of ancient bony fishes is lobe-finned fish. As a result of hereditary variability and the action of natural selection, the formation of lobe-finned fish dismembered limbs, adaptations to air breathing, development of a three-chambered heart. Origin from lobe-finned fishes of ancient amphibians.
4. Origin ancient reptiles. Habitat of ancient amphibians - wet places, shores of reservoirs. Penetration into the interior of the land by their descendants - ancient reptiles, which acquired adaptations for reproduction on land; instead of the mucous glandular skin of amphibians, a horny covering was formed, protecting the body from drying out.
5. Origin birds and mammals. Ancient reptiles are the ancestors of ancient higher vertebrates - birds and mammals. Signs of their higher organization: a highly developed nervous system and sensory organs; four-chambered heart and two circles of blood circulation, eliminating the mixing of arterial and venous blood, more intense metabolism; highly developed respiratory system; constant body temperature, thermoregulation, etc. The development of primates, from which man descended, is more complex and progressive among mammals.
The root cause of all evolutionary transformations in the living world is changing environmental conditions. If it didn’t adapt, the individual→species died out, etc. According to science, it is natural selection due to the struggle for existence. Here it is worth considering all three types: intraspecific, interspecific, fight against unfavorable conditions. Initially, the habitat was aquatic, then life moved to land. The number of individuals and species increased in the original environment, and the amount of resources (food) per unit of individuals decreased. Landing is a very important evolutionary step. What allowed them to do this? Transformations in the musculoskeletal system: cartilaginous → bone skeleton, muscles are difficult to differentiate for complicated movements. Plus the force of gravity and the density of the medium are different than in water. Body coverings: scales covered with mucus, breathing with gills of oxygen dissolved in water (fish) → skin covered with mucus, but breathing is already cutaneous + pulmonary, and also with atmospheric oxygen (amphibians). At this stage, the connection with water has not yet been lost, both in terms of breathing and in terms of reproduction. Reptiles are a transitional link in evolutionary transformations: scaly skin, without glands, saves body moisture from evaporation, reproduction is no longer associated with water. And a complete transition to ground-air environment these are birds and mammals. The only difference is that birds are a specialized branch for flight. That. evolution proceeded from the aquatic to the ground-air environment, and all organ systems were transformed to suit new conditions. Causes? Lack of space, food, strong pressure own and other species →struggle for existence→natural selection→adaptability to new environment a habitat.
Lesson type - combined
Methods: partially search, problem presentation, reproductive, explanatory and illustrative.
Target: mastering the ability to apply biological knowledge in practical activities, use information about modern achievements in the field of biology; work with biological devices, instruments, reference books; conduct observations of biological objects;
Tasks:
Educational: the formation of cognitive culture, mastered in the process of educational activities, and aesthetic culture as the ability to have an emotional and value-based attitude towards objects of living nature.
Educational: development of cognitive motives aimed at obtaining new knowledge about living nature; cognitive personality traits associated with mastering the basics scientific knowledge, mastering methods of studying nature, developing intellectual skills;
Educational: orientation in the system moral standards and values: recognition of the high value of life in all its manifestations, the health of one’s own and other people; environmental consciousness; nurturing love for nature;
Personal: understanding of responsibility for the quality of acquired knowledge; understanding the value of adequately assessing one’s own achievements and capabilities;
Cognitive: ability to analyze and evaluate the impact of environmental factors, risk factors on health, the consequences of human activities in ecosystems, the impact of one’s own actions on living organisms and ecosystems; focus on continuous development and self-development; ability to work with various sources information, convert it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.
Regulatory: the ability to organize independent completion of tasks, evaluate the correctness of work, and reflect on one’s activities.
Communicative: formation of communicative competence in communication and cooperation with peers, understanding of the characteristics of gender socialization in adolescence, socially useful, educational and research, creative and other types of activities.
Technologies: Health conservation, problem-based, developmental education, group activities
Types of activities (content elements, control)
Formation in students of activity abilities and abilities to structure and systematize the subject content being studied: collective work - study of text and illustrative material, compilation of a table “Systematic groups of multicellular organisms” with the advisory assistance of student experts, followed by self-test; pair or group performance laboratory work with the advisory assistance of a teacher followed by mutual verification; independent work based on the material studied.
Planned results
Subject
understand the meaning of biological terms;
describe the structural features and basic life processes of animals of different systematic groups; compare the structural features of protozoa and multicellular animals;
recognize organs and organ systems of animals of different systematic groups; compare and explain reasons for similarities and differences;
establish the relationship between the structural features of organs and the functions they perform;
give examples of animals of different systematic groups;
distinguish the main systematic groups of protozoa and multicellular animals in drawings, tables and natural objects;
characterize the directions of evolution of the animal world; provide evidence of the evolution of the animal world;
Metasubject UUD
Cognitive:
to Work with different sources information, analyze and evaluate information, transform it from one form to another;
write theses, different kinds plans (simple, complex, etc.), structure educational material, give definitions of concepts;
carry out observations, perform elementary experiments and explain the results obtained;
compare and classify, independently choosing criteria for the specified logical operations;
build logical reasoning, including establishing cause-and-effect relationships;
create schematic models highlighting the essential characteristics of objects;
identify possible sources of necessary information, search for information, analyze and evaluate its reliability;
Regulatory:
organize and plan your educational activities— determine the purpose of the work, the sequence of actions, set tasks, predict the results of the work;
independently put forward options for solving assigned tasks, anticipate the final results of the work, choose the means to achieve the goal;
work according to plan, compare your actions with the goal and, if necessary, correct mistakes yourself;
master the basics of self-control and self-assessment for making decisions and making informed choices in educational, cognitive and educational and practical activities;
Communicative:
listen and engage in dialogue, participate in collective discussion of problems;
integrate and build productive interactions with peers and adults;
adequately use speech means for discussion and argumentation of one’s position, compare different points point of view, argue your point of view, defend your position.
Personal UUD
Formation and development of cognitive interest in the study of biology and the history of the development of knowledge about nature
Techniques: analysis, synthesis, inference, translation of information from one type to another, generalization.
Basic Concepts
Concepts: divergence, variety, speciation.
During the classes
Updating knowledge ( concentration when learning new material)
Choose the correct answer option in your opinion.
1. What two main factors of evolution did Darwin identify?
heredity and variability
natural selection and heredity
hereditary changes and natural selection
2. What is the ability of organisms to transmit their characteristics and developmental characteristics to their offspring?
variability
heredity
natural selection
3. What is the name of the main evolutionary process, as a result of which the number of individuals with maximum fitness increases in a population, and those with unfavorable fitness decrease?
natural selection
variability
evolution
4. What is the name of the natural process of development of living nature??
evolution
revolution
heredity
5. How many types of variability are observed?
6. What are the changes caused by the occurrence of different types of mutations and their combinations in subsequent crosses called?
hereditary
quality
non-directional
7. What are the changes in the body associated with a change in phenotype called?
hereditary variability
non-directional variability
modification variability
8. What is the name of a persistent transformation of the genotype that occurs under the influence of the external or internal environment?
mutation
metamorphosis
inheritance
9. How many types of natural selection are there?
10. What is the change in gene allele frequency from generation to generation called?
heredity
variability
genetic drift
Learning new material(teacher's story with elements of conversation)
Complication of the structure of animal organisms
The complication of the structure of animal organisms occurred throughout the entire period of development of the animal world on Earth. Let's turn the pages of this story again and denote major milestones in the evolution of animals.
The first animals on Earth were also the most ancient prokaryotes. Later, protozoa appeared, from which modern unicellular organisms originate (ciliates, Sarcoflagellates, etc.). Colonial forms of ancient unicellular organisms gave rise to the first multicellular organisms, consisting of specialized cells.
The next stage in evolution was the appearance of three-layered animals similar to planaria. Unlike the two-layer ones, these new forms of animals had organ systems: digestive, circulatory, nervous, excretory, reproductive, and muscular. The nervous system evolved from a diffuse one in two-layer animals to a stem system in three-layer animals.
The appearance of the body cavity - first primary and then secondary - is the next important stage in the evolution of animals. Ancient ringed worms with their closed circulatory system, the ventral nerve cord was opened new page in the history of the development of the animal world. Then, according to scientists, events developed in two directions: the evolution of arthropods and mollusks began from some annelids, and the evolution of chordates from others. Evolving in these directions, animals “acquired” respiratory organs. The structure of their nervous systems has also become more complex, and, consequently, the way of life of these animals.
The next milestone in evolution was the exploration of land by animals. Animals developed tracheas and lungs - organs adapted to gas exchange in atmospheric air, as well as a second circle of blood circulation. Adaptations to life on land were changes in the reproduction and development of animals: internal fertilization, the appearance of eggs covered with a durable shell in reptiles and birds, intrauterine development of embryos in mammals, care for offspring. Life on land requires adaptations that protect the body from excessive loss of water, so the coverings of animals have changed. The organs also underwent changes musculoskeletal system: limbs appeared that allow you to run, jump, and fly. The nervous system and forms of animal behavior have become more complex. Warm-blooded animals and birds have colonized different parts of the planet.
Diversity of species as a result of evolution.
The amazing variety of forms and body structures of animals is the result of natural selection. This occurs due to the constant accumulation in descendants of traits that are useful to them in given conditions of existence. The accumulation of such characteristics useful for the species leads to a complication of the structure of animals.
Thus, birds have a streamlined body, a lightweight skeleton, which facilitates rapid movement in the air with the help of wings. Aquatic animals, such as whales, dolphins, and fur seals, have a torpedo-shaped body, adapted for rapid movement in the aquatic environment. Land animals have well-developed limbs for moving quickly on the ground. Underground animals, such as moles and mole voles, lead a burrowing lifestyle. Small animals are covered with short thick hair, which prevents particles of earth from getting on the skin, and have powerful forelimbs adapted for digging underground passages.
The existing vertebrates - fish, amphibians, reptiles, birds and mammals, characterized by a progressive complication of organization, arose on the basis of hereditary variability, the struggle for existence and natural selection in the course of long historical development.
The fauna around us is rich not only in a large number of individuals, but also in the diversity of species. Each individual of any species is adapted to life in the conditions of its habitat. If a large group of representatives of any species finds themselves in different conditions or they switch to feeding on different foods, this may lead to the appearance of new characteristics or adaptations. If these new adaptations, under different conditions, turn out to be useful for the migrated animals, then, thanks to natural selection, the newly acquired characteristics will be preserved in their ranks and will be passed on from generation to generation. Thus, in the process of evolution, several new ones can be formed from one species. The process of divergence of characters in related organisms was called divergence by Charles Darwin.
An example of divergence is the small birds finches on the Galapagos archipelago. Darwin's finch species differ in the shape and size of their beaks. Darwin found that finches, which had a small sharp beak, fed on larvae and adult insects. Finches with a powerful massive beak fed on tree fruits. Gradual transitions in the variability of these beaks in finches were also noted. Thus, in the process of evolution, due to the divergence of characters determined by the direction of natural selection, speciation occurred. The emergence of a new species, as Darwin noted, is preceded by the formation of intermediate forms - varieties. This evolutionary process ends with the formation of new species.
Through divergence and the directed action of natural selection, a variety of species is formed in nature.
Do you know that:
The diversity of extinct reptiles serves as an example of their divergence based on different living conditions. Animals of the same species living over a large area are usually heterogeneous. Their study shows the divergence of characters in individuals and the beginning of the formation of new systematic groups. Thus, the common fox, which lives almost throughout Russia, has about 20 subspecies.
Independent work
Let's give examples of useful signs.
In birds: streamlined body shape, feather cover, lightweight skeleton, wings.
In aquatic animals: a torpedo-shaped body, flippers, fins - modified forelimbs.
Underground animals have short, thick hair, powerful digging forelimbs.
2. Let's write about the formation of new species.
When living conditions change for some representatives of one species, new characteristics will appear that will be useful and will be preserved in the descendants of the representatives, will be fixed in them due to natural selection and will be passed on from generation to generation. This process of divergence of characteristics is called divergence.
3. Finish the sentence.
The process of divergence of characters, according to Charles Darwin, is called divergence.
4. Let's explain the situation.
When representatives of one species find themselves in other conditions, they will develop new characteristics that will be useful, and will be preserved in the descendants of these representatives, will be fixed in them thanks to natural selection and will be passed on from generation to generation. As a result, several new species may arise from one.
5. Let us describe the beaks of finches feeding
Insects: small sharp beak.
By seeds: larger, more powerful beak.
Cacti: large and sharp beak.
Let us draw a conclusion about the differences in their structure.
The beaks of finches have acquired differences due to different types nutrition in birds. There was a divergence and the formation of varieties of finches.
Diversity of species in nature
Reasons for evolution. Evolution and diversity
Results of evolution: diversity of species and adaptability of organisms to their environment
Biology lesson "Species diversity as a result of evolution"
Resources
Biology. Animals. 7th grade textbook for general education. institutions / V.V. Latyushin, V.A. Shapkin.
Active formsAndbiology teaching methods: Animals. Kp. for the teacher: From work experience, -M.:, Education. Molis S. S.. Molis S. A
Work program in biology 7th grade for teaching materials V.V. Latyushina, V.A. Shapkina (M.: Bustard).
V.V. Latyushin, E. A. Lamekhova. Biology. 7th grade. Workbook to the textbook V.V. Latyushina, V.A. Shapkina “Biology. Animals. 7th grade". - M.: Bustard.
Zakharova N. Yu. Tests and tests in biology: to the textbook by V. V. Latyushin and V. A. Shapkin “Biology. Animals. 7th grade” / N. Yu. Zakharova. 2nd ed. - M.: Publishing house "Exam"
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