Common features of the chordate type. Chordate animals - general characteristics of the type and examples of animals

Chordates are a type of animal characterized by a variety of representatives who have achieved evolutionary progress. In our time, there are about 60 thousand species of chordates. These include fish, frogs, lizards, birds, animals, etc. Representatives of chordates live in water, on land, in air and soil. In the course of evolution, they have adapted to a wide variety of environmental conditions.

Despite their diversity, all chordates have a general body plan that resembles the general body plan of most invertebrates inverted in the dorso-abdominal direction. In chordates, the neural tube is located above the intestines (and notochord or spine), blood flows on the ventral side of the body from tail to head, on the dorsal side - from head to tail. And most invertebrates have an abdominal nerve chain, blood flows in the opposite direction compared to chordates (on the back - from tail to head, on the belly - from head to tail).

The main distinguishing feature of chordates is the presence of an internal axial skeleton. In the most primitive representatives (lancelet, some groups of fish), the chord plays the role of the axial skeleton, which looks like a dense elastic, but rather elastic longitudinal cord (rod). It is made up of cartilaginous tissue. In most of the more highly organized representatives of the chordates, in the process of embryonic development, the vertebral column (spine) develops in place of the chord. It can be cartilage or bone. The chord is formed from a longitudinal outgrowth of the intestinal tube from the dorsal side, that is, it has an endodermal origin.

It was in the chordate type that the nervous system reached its highest development. The tubular nervous system is characteristic. The neural tube is laid over the notochord and is of ectodermal origin. In most, the anterior neural tube expands to form the brain. In this case, the neurocoel (the cavity of the neural tube) is transformed into the ventricles of the brain.

The alimentary tube is located under the chord, and under the alimentary tube is the heart (or a vessel similar to it).

Gills are not formed on the surface of the body, but inside it - in the pharynx. Thus, the pharynx is permeated with gill openings. They are preserved in all primary aquatic chordates, in the rest - only embryos in the initial stages of their development have gills.

The circulatory system of chordates is closed.

Chordates belong to the group of deuterostomes, since in the process of embryonic development their mouth is formed not from the side of the protrusion of the blastula, as in most invertebrates, which are therefore called protostomes, but from the opposite side. An anus develops at the site of the invagination of the blastula in chordates.

All chordates belong to secondary cavities.

The phylum Chordata includes three subtypes. These are cephalochordates, or non-cranial (lancelets), larval-chordates (tunicates) and vertebrates, or cranial (all the rest). In tunicates, the notochord is present only at the larval stage. The Vertebrate subtype is the most numerous in terms of species composition and prevalence.

Chordates are animals with a high organization and a developed nervous system. Chordates are fast in movement, can easily get their own food, quickly adapt to a changing environment. About 40 thousand species of Chordates inhabit our planet.

There are representatives of Chordates of small size (ascidians), and large individuals (blue whale weighing up to 160 tons), live in water bodies, air, on the expanse of land, in the depths of the soil. They are diverse, but they are characterized by common properties.

Chordates have internal skeleton- chord. This is a support structure that stretches along the body like an elastic cord, is formed from the endoderm. It is present in the embryonic stage in all representatives. In the process of development, in highly developed Chordates it is replaced by inert tissue, forming the spine, in the lower ones it remains for the entire period of existence.

Nervous system Chordate animals are represented by the neural tube, which is located near the chord, inside there is a band formation - a neurocele. The anterior part of higher animals is transformed into hemispheres.

Bilateral symmetry(mirror reflection of internal organs) was formed evolutionarily as an adaptation to crawling on the surface, in actively moving individuals.

Visceral fissures located in the pharynx in the form of two holes. In the embryonic period, gills are located on their walls, which are preserved in lower animals, they do not function in other representatives.

Origin of Chordates

To this day, it has not been possible to form a single point of view on the origin of the Chordates. This question was asked by scientists in the 19th century. It was assumed that their ancestors may have been arthropods, but soon this hypothesis was refuted, due to significant differences between them in the embryonic period.

Next hypothesis: the origin of the Chordata from the coelenterates(due to the presence of gill slits, stomochord). Over time, it turned out that they have more differences than similarities. Modern biologists still cannot solve this problem.

A group of deuterostomes is distinguished, which have a number of similar features with Chordates:

• The structure of the digestive system;
• nervous system;
• circulatory system.

It is assumed that the predecessors of the Chordates were free-swimming animals, which were divided into inactive individuals Lancelet and Shell, and another branch gave Vertebrates, which actively began to develop. The sides of the body of vertebrates have made a coup: the transition from the ventral to the dorsal side. It is believed that this event became a key event in their further evolution.

Systematics of Chordates

The phylum Chordata is divided into three subtypes.

Subtype Tunicates (larval chordates) has about 1000 species that have a chord only in the initial stages of development.

Ascidian class leads a sedentary lifestyle, they cling to stones at the bottom of the sea, or to the base of ships, forming continuous layers of small individuals. Ascidians have openings: the mouth serves as a filter for the trapped water, the filtered food enters the intestines and then the products of digestion are excreted through the anus.

Salps and Appendiculars able to move freely in the water.

Tunicates are hermaphrodites(both testes and ovaries are present), larvae emerge from the eggs, which bear little resemblance to an adult, have signs of an internal skeleton, which indicates a relationship with vertebrates.

Subtype Cranial- marine inhabitants of the near-bottom territory, retained the signs of typical chordates (neural tube, gills, notochord). The brain is not developed, they lead a primitive way of existence, reaching a maximum size of 7 cm, representatives are dioecious individuals, spawn, live in the sands at the bottom of the sea depths and oceans, leaving only a part of the body with an oral cavity for food outside. Allocate one Class Lancelets.

Subtype Vertebrates- highly organized individuals, with the presence of developed hemispheres of the brain and cranium, the spinal column, which serves as a protective sheath for the spinal cord. In the process of evolution, they received a complex morphological structure, improved sense organs, switched from a sedentary lifestyle, began to easily move across the expanses of earth, air and water. Vertebrates include amphibians, fish, birds, reptiles, mammals and cyclostomes.

Classification of Chordates - scheme

Features of the structure of chordates

What features of the structure were formed in chordates in the process of evolution?

Skin in non-cranial they consist of a single-layer epithelium, in vertebrates it is fluff, feathers, scales, and also from derivatives of the epidermis - claws, horns, hooves. There are glands that secrete sweat, sebum, odorous substances. For example, in cows, goats, sheep, mammary glands are formed to feed offspring.

Phylogenesis circulatory system chordates comes from the mesoderm, a circle of blood circulation is formed (closed), the heart is in the abdominal region, the dorsal and abdominal arteries, which are connected by anastomoses. The walls of blood vessels are expelled by endothelial cells, which helps to maintain homeostasis, the amount of blood glucose and proteins has increased (rudiments of immunity).

Nervous system in the embryonic period, it looks like a layer of thickened ectoderm, its endings are closed and form a neural tube. The phylogenesis of the brain of chordates comes from the anterior end of the neural tube, the dorsal from the posterior. The formation of the brain (cephalization) has become a necessary condition for the evolutionary development of Chordates. They began to distinguish external stimuli, to perceive the world around them with the help of their senses. Higher chordates have a brain with five divisions, which were formed from three cerebral vesicles.

The development of the respiratory system and the digestive system is closely connected; there is a common laying under the guise of a straight tube, which in higher chordates is differentiated into two independent systems.

In the lower chordates digestive tract has no departments, in lancelets, the mouth opening with many tentacles communicates with the pharynx, where the filtering apparatus is located, then the food is then sent through the posterior groove to the intestine and excreted by the anus, the glands are not developed. In vertebrates, the digestive system already consists of separate structures: the pharynx, esophagus, gastrointestinal tract, secreting glands appear: the liver and pancreas.

Breath carried out by gills and lungs (terrestrial vertebrates). After leaving the water, amphibians have formed lungs, but their functionality is insufficient, so additional gas exchange is carried out through the skin. Thus, for the Class Amphibians, skin-pulmonary respiration is characteristic.

The class Birds is characterized by the presence of double breathing.. The respiratory apparatus consists of the larynx, trachea, bronchi, lungs with air sacs. During the flight, birds use air sacs for gas exchange, the inhaled air passes through the lungs twice - both on inhalation and on exhalation - this is the mechanism of double breathing.

breeding system in chordates, it is represented by testes and vas deferens in males, ovaries and oviducts in females. Chordates, with the exception of larval-chordates, are dioecious.

Chordates ( Chordata listen)) is a phylum of animals that includes vertebrates, larval-chordates, and non-cranial. Vertebrates such as birds and fish are the best known, and are the subtype of animals to which humans belong.

Chordates are bilaterally symmetrical, which indicates the existence of a line of symmetry that divides their body into two halves that are almost mirror images of each other.

Bilateral symmetry is found not only in chordates, but also in and (although in the case of echinoderms they are bilaterally symmetrical only during the larval stage of their life cycle, and pentaradial symmetry is shown in adults).

All chordates have a notochord that is present during some or all of their life cycle. The chord (or dorsal string) is a semi-flexible rod to which the large muscles of the animal are attached. It also plays an important role in signaling and coordinating development.

The chord consists of flat, enclosed in a fibrous sheath. In vertebrates, the dorsal string is present only during the embryonic stage of development, and then the vertebrae develop around it and the spine forms. In tunicates, the notochord remains throughout the entire life cycle of the animal.

Chordates have a single hollow dorsal nerve cord that runs down the back of the animal and, in most species, forms the brain at the front of the body. They also have gill slits that serve as openings between the pharyngeal cavity and the external environment, as well as for filtering water.

Another characteristic of chordates is a structure called the endostyle, a groove-like organ that sits against the wall of the pharynx and secretes mucus and also catches small food particles that enter the pharyngeal cavity. Endostyle is present in tunicates and lancelets. In vertebrates, the endostyle is replaced by the thyroid gland, an endocrine gland located in the neck.

Main characteristics

• chord;
• neural tube (strand);
• gill slits;
• endostyle or thyroid gland;
• muscular tail.

Species diversity

More than 75,000 animal species belong to the chordate phylum.

Classification

Chordates are classified in the following taxonomic hierarchy:

• Domain: eukaryotes ( Eukaryota);
• Kingdom: Animals ( Animalia);
• Type of: Chordates ( Chordata).

Chordates, in turn, are divided into the following subtypes:

• Skullless ( Acrania) : now there are about 32 species of non-cranial. Representatives of this subtype have chords that persist throughout their life cycle. Lancelets are the only non-cranial family whose members are marine animals with long, narrow bodies. Earliest known fossil lancelet, Yunnanozoon, lived about 530 million years ago at the time. Fossils of these organisms have also been found in the famous Burgess Shale in British Columbia.
• Larval chordates, or tunicates ( Urochordata) : currently there are about 1600 species of tunicates. This subtype is subdivided into classes such as ascidians and appendiculars. Tunicates are marine filter feeders, most of which do not move, but attach themselves to rocks or other hard surfaces on the seabed.
• (Vertebrata) - Today there are about 57,000 species of vertebrates. Members of this group include lampreys, mammals, birds, amphibians, reptiles, and fish. During development, the notochord of vertebrates is replaced by the vertebral column.

1.General characteristics of the chordate type.Type Chordates combines animals that are very diverse in appearance, lifestyle and living conditions. Representatives of chordates are found in all the main environments of life: in water, on the land surface, in the thickness of the soil and, finally, in the air. They are geographically distributed throughout the world. The total number of species of modern chordates is approximately 40 thousand. The Chordata type includes non-cranial (lancelets), cyclostomes (lampreys and hagfish), fish, amphibians, reptiles, birds and mammals.

2. The main features of the type are chordates. Despite the huge diversity, all representatives of the Chordata type are characterized by common features of organization that are not found in representatives of other types. Let's consider the main features of the type using an interactive scheme: The body is two-sided - symmetrical. Intestine through. Above the intestines is a chord. Above the chord, on the dorsal side of the body, is the nervous system in the form of a neural tube. The walls of the pharynx have gill slits. The circulatory system is closed. Heart on the ventral side of the body, under the alimentary canal. They live in all environments.

3. General taxonomy of the Chordata type. Of the four subtypes of chordates - hemichordata, larval-chordate Urochordata, non-cranial Acrania and vertebrate Vertebrata - we will focus on the last two, related to the progressive direction in the evolution of this type of animal. The subtype Cranial consists of only one class - Cephalochordata, which includes the lancelet; The subphylum Vertebrates includes the following classes: Cyclostomata Cyclostomata, Chondrichthyes Cartilaginous Fishes, Osteichthyes Bony Fishes, Amphibia Amphibians, Reptilia Reptiles, Aves Birds and Mammalia Mammals.

4. Origin of the Chordate type. Chordates are one of the largest types of the animal kingdom, whose representatives have mastered all habitats. This type includes three groups (subtypes) of organisms: tunicates (including marine sessile organisms living at the bottom - ascidians), non-cranial (similar to small fish sea creatures - lancelets), vertebrates (cartilaginous and bony fish, amphibians, reptiles, birds and mammals). Man is also a representative of the chordate type. The origin of the chordate type is the most important stage in the historical development of the animal world, which means the emergence of a group of animals with a unique structural plan, which made it possible in further evolution to achieve the maximum structural and behavioral complexity among living beings.

5.General characteristics of the subtype Shellers.hullers, or larval-chordates(lat. Tunicata, Urochordata listen)) is a subphylum of chordates. Includes 5 classes - ascidians, appendiculars, salps, fire-bearers and marrowers. According to another classification, the last 3 classes are considered units of the class Thalacea. More than 1000 species are known. They are found in seas around the world. The body is bag-shaped, surrounded by a shell or mantle ( Tunica) from tunicin, a material similar to cellulose. The type of food is filtering: they have two openings (siphons), one for the absorption of water and plankton (oral siphon), the other for its release (cloacal siphon). The circulatory system is not closed, a notable feature of the tunicates is a regular change in the direction in which the heart pumps blood.

6. Organization of Ascidians as typical representatives of tunicates. Ascidians are benthic animals leading an attached lifestyle. Many of them are single forms. Their body sizes are on average several centimeters in diameter and the same in height. However, some species are known among them that reach 40-50 cm, for example, the widespread Cione intestinalis or the deep-sea Ascopera gigantea. On the other hand, there are very small sea squirts, less than 1 mm in size. The alimentary canal of ascidians begins with a mouth located at the free end of the body on the introductory, or oral, siphon.

8. General characteristics of the subtype Cranial. Skullless- marine, mainly bottom animals that retain the main features of the Chordata type throughout their lives. Their organization represents, as it were, a diagram of the structure of a chordate animal: as an axial skeleton, they have chord, the central nervous system is represented neural tube, throat pierced gill slits. Available secondary mouth and secondary body cavity in general. In a number of organs, there is metamerism. Skullless animals are characterized bilateral (bilateral) symmetry body. These signs point to the phylogenetic relationship of the non-cranial with certain groups of invertebrates (annelids, echinoderms, etc.).

9.External and internal structures of the lancelet as a representative of the non-cranial subtype . lancelet (Amphioxus lanceolatus This small animal (6 - 8 cm long) lives in the shallow waters of the seas, burrowing into the bottom soil and exposing the front part of the body. The non-cranial, and in particular the lancelet, are characterized by a number of specific primitive features that distinguish them well from other representatives of the Chordata type. The skin of the lancelet is formed by a single layer of epithelium (epidermis) and is covered by a thin cuticle. The central nervous system is not differentiated into the brain and spinal cord. Due to the lack of a brain, there is no skull. The sense organs are poorly developed: there are only tactile cells with sensitive hairs (these cells are scattered over the surface of the body) and light-sensitive formations - eyes Hesse located in the walls of the neural tube. The gill slits do not open outwards, but into the atrial, or peribranchial, cavity resulting from the fusion of the lateral (metapleural) skin folds. The digestive system consists of a poorly differentiated tube, in which only two sections are distinguished - pharynx and intestine. The blood of the lancelet is colorless, the heart is missing. The reproductive organs - the testes and ovaries - are similar in external structure and are rounded bodies.

11. General characteristics of the subtype Vertebrates. External features of the structure. The cranial subphylum includes all known vertebrates, whose likely evolutionary relationships are shown in. existence on land. Thus, reptiles are the first fully terrestrial vertebrates. Zoologists sometimes use the collective term amniotes for all wholly terrestrial vertebrates (reptiles, birds, and mammals), in contrast to anamnia (amphibians and fish), in which the amniotic membrane is absent, and therefore they are necessarily forced to spend part of their life cycle or all of them in water. . The highest subtype of the chordate type, whose representatives have a bony or cartilaginous internal skeleton. It is divided into superclasses of fish and (jawless, cartilaginous fish and bony fish) and tetrapods (amphibians, reptiles, birds and mammals). The vertebrate subtype includes the following classes: fish, amphibians, reptiles, birds, and mammals.

13. Primitive, peculiar and specialized features of the class Cyclostomes. The only surviving representatives of the jawless - lampreys (Petromyzones) and hagfish (Myxini) - make up the class of cyclostomes (Cyclostomata), the most ancient of modern vertebrates. In contrast to the representatives of all higher classes, they do not have real jaws and their mouth does not open directly outward, but is placed in the depths of a kind of suction funnel, which is supported by a special ring-shaped cartilage. Their skin is bare and slimy. True teeth are absent; instead, the oral funnel is armed with horny teeth. Paired limbs cyclostomes are deprived. The nasal opening is one, unpaired, since the organs of smell are combined into one nasohypophyseal sac. The visceral skeleton looks like an openwork lattice and is not divided into separate segmented arches. Finally, the respiratory organs of cyclostomes are represented by 5-15 pairs of peculiar gill sacs of endoderm origin.

15. Systematics of the section Jawless. (up to representatives). Jawless(lat. Agnatha) - an archaic group (superclass or clade) of chordate cranials, almost completely extinct in our time, with the exception of 39 lamprey species and 76 hagfish species. Jawless are characterized by the absence of jaws, but they have a developed skull, which distinguishes them from non-cranial. Mixins and lampreys have traditionally been considered a monophyletic group and have been grouped together under the name cyclostomes (Cyclostomata). But there is also an alternative hypothesis, according to which minohyphylogenetically is closer to gnats than to hagfishes.

16. General characteristics of the class Cartilaginous fish in connection with an active lifestyle. CLASS CHONDRICHTHYES. Cartilaginous fish originated in the Upper Silurian from jawless fish, moving to faster, longer swimming and more successful capture of prey with armed jaws by the mouth. They were the first jawed vertebrates and dominated, gradually evolving, until the middle of the Mesozoic era, when they began to be replaced by higher bony fish. Currently, there is only one small group of carnivorous cartilaginous fish called elasmobranchs. They are widely distributed in the seas. The elasmobranchs include sharks - excellent swimmers - and rays, leading a sedentary lifestyle at the bottom. Sharks are about 350 species, stingrays are about 340 species. Most cartilaginous fish are large in size. The length of the largest sharks reaches 15-20 m, rays - 6-7 m. There are few small species.

17. Systematics of the class Cartilaginous fishes. class Cartilaginous fishes (lat. Chondrichthyes). It is one of two existing classes of fish. The class of cartilaginous fishes is divided into the subclass Elasmobranchii or laminobranchs and the subclass Holocephali or whole-headed fishes. The best-known members of this class are the Selachii or sharks and the Batoidea or rays. Both those and others belong to the subclass of laminabranchs.

20. Primitive Featuresstructures of organ systems of cartilaginous fishes. All cartilaginous fish are characterized by the following primitive features: the skin is either covered with placoid scales or naked (in chimeras and some rays), gill slits open outward, like lampreys, and only chimeras have skin membranes covering the gill slits. The skeleton has no bones and is formed exclusively by cartilage (which, however, is often saturated with lime), unpaired fins and the distal part of paired fins are supported by elastin (“horny”) rays, there are wide interbranch septa, usually reaching the surface of the body, there is not a swim bladder, no lungs.

18. The external structure of the shark as the first jawed vertebrates. sharks(lat. Selachii) - above the order of cartilaginous fish (Chondrichthyes), belonging to the subclass of gill plates (Elasmobranchii) and having the following distinctive features: an elongated body of a more or less torpedo-shaped shape, a large heterocercal caudal fin, usually a large number of sharp teeth on each jaw. The word "shark" comes from the Old Norse "hákall". The most ancient representatives already existed about 420-450 million years ago. To date, more than 450 species of sharks are known: from the deep-sea shallow Etmopterus perryi, only 17 centimeters long, to the whale shark (Rhincodon typus) - the largest fish (its length reaches 20 meters). Representatives of the above detachment are widespread in the seas and oceans, from the surface to a depth of more than 2000 meters. They mainly live in sea water, but some species are also able to live in fresh water. Most sharks are so-called real predators, but 3 species - whale, giant and large-mouthed sharks - filter feeders, they feed on plankton, squid and small fish.

19. Progressive features of the structure of the organ systems of cartilaginous fish. These most primitive fish include sharks, rays and peculiar chimeras that inhabit the seas and oceans everywhere. Some live in fresh water. Along with very ancient features of organization, modern cartilaginous fish have a highly developed nervous system and sensory organs and a very perfect biology of reproduction. The characteristic features also include the following progressive features of organization that bone fish do not have: brain, males have peculiar copulatory organs, representing modified parts of the ventral fins, insemination is internal, and females either lay large eggs covered with a dense horn-like membrane, or give birth to live cubs, the development of which occurs in the "womb".

21. Systematics of the class Bony fish. Bone fish(lat. Osteichthyes) is a group of classes in the superclass Pisces ( Pisces). Bony fish have paired limbs (fins). The mouth of these fish is formed by grasping jaws with teeth, the gills are located on the gill arches with an internal skeletal support, the nostrils are paired. From the oral cavity, food passes into the pharynx, from it into the esophagus, and then into the voluminous stomach or immediately into the intestines. Partial digestion of food occurs in the stomach under the influence of gastric juice. The final digestion of food takes place in the small intestine. The duct of the gallbladder, liver and pancreatic duct flows into the initial section of the small intestine. In the small intestine, nutrients are absorbed into the blood, and undigested food debris is removed through the anus. Gill breathing. From the oral cavity, water passes through the gill slits, washes the gills and exits from under the gill covers. Gills are made up of gill arches, which in turn are made up of gill filaments and gill rakers. The circulatory system of fish is closed, the heart consists of 2 chambers: the atrium and the ventricle. From the ventricle to the gills, a large blood vessel departs - aorta, branching into smaller ones - arteries. In the gills, the arteries form a dense network of tiny vessels - capillaries. Substances that are unnecessary for the body are excreted from the blood when they pass through the excretory organs - the kidneys. Two ureters depart from the kidneys, through which urine flows into the bladder, and is removed outward through the opening behind the anal. In most species, fertilization is external. In species with internal fertilization, the copulatory organ of males is formed by a modified part of the anal fin.

22. Features of the progressive organization of the class Bony fish. In bony fish, the cartilage in the skeleton is to some extent replaced by bone tissue: the main or replacement bones are formed. In addition, integumentary bones appear in the skin, which then sink under the skin and are part of the internal skeleton. The skeleton of bony fish is subdivided into the axial skeleton, the skull (cerebral and visceral), the skeleton of unpaired fins, the skeleton of paired fins and their belts.

24. Features of the structure of organ systems of bony fish, as progressive aquatic vertebrates. They have scales of the ganoid, cycloid or ctenoid type. The skeleton is bony. In the internal cavity of bony fish are the organs of digestion, blood circulation, excretion and reproduction. The complex of progressive features in the structure of bony fishes is especially clearly and fully expressed in the youngest and most progressive branch of this class, Teleostei bony fishes, which includes the vast majority of living forms of this class.

26.Subclass Ray-finned as the main group of the class bony fish, its characteristics. ray-finned fish(lat. Actinopterygii listen)) is a class of fish from the superclass bony fish. The vast majority of known modern fish species (over 20,000 or about 95%) are ray-finned. Representatives of this particular subclass inhabit water bodies of all types: from many kilometers deep ocean and salt lakes to streams and underground sources. Fish scales are ganoid or bony. Some scales, merging, form bony plates, while others have bare skin. A well-developed notochord has been preserved only in a few species, usually fish have bony vertebrae. In ray-finned swim bladders, in a few species it is secondarily reduced.

27. General characteristics of the Amphibian class, as the first terrestrial vertebrates. Amphibians, or amphibians (lat. Amphibia) - a class of vertebrate tetrapods, among others including newts, salamanders, frogs and caecilians - in total more than 6700 (according to other sources - about 5000) modern species, which makes this class relatively few. In Russia - 28 species, in Madagascar - 247 species. The group of amphibians belongs to the most primitive terrestrial vertebrates, occupying an intermediate position between terrestrial and aquatic vertebrates: reproduction and development in most species occurs in the aquatic environment, and adults live on land. All amphibians have smooth thin skin, relatively easily permeable to liquids and gases. The structure of the skin is characteristic of vertebrates: a multilayered epidermis and the skin itself (corium) stand out. The skin is rich in skin glands that secrete mucus. In some, the mucus may be poisonous or facilitate gas exchange. The skin is an additional organ for gas exchange and is supplied with a dense network of capillaries. Horn formations are very rare, and ossification of the skin is also rare: Ephippiger aurantiacus and the horned toad of the species Ceratophrys dorsata have a bone plate in the skin of the back, legless amphibians have scales; in toads, sometimes, under old age, lime is deposited in the skin.

23. External structure of bony fish and its diversity. The movement of bony fish is carried out with the help of fins. The mouth is armed with movable jaws. New features of a higher organization in this class are manifested primarily in the ossification of their internal skeleton and in the appearance of various bone formations in the skin in many species. This makes the musculoskeletal system of the body stronger, protects the internal organs. Significant changes are noticeable in the structure of the gill apparatus: bony fish have developed gill covers that protect the respiratory organs.

29. Systematics of the Amphibian class. Amphibians are the smallest class of vertebrates, including only about 2100 modern species. Of all classes of vertebrates, amphibians occupy the most limited space on the globe, being associated with the coastal parts of only fresh water bodies, and are absent both in the sea and on oceanic islands. Modern amphibians are represented by three orders, very different in number of species. The most numerous are tailless amphibians (Ecaudata, or Anura), which have adapted to moving on land by jumping with the help of elongated hind limbs (hence their name jumping - Salientia) and distributed throughout all continents. More primitive are the tailed amphibians (Caudata, or Urodela), whose typical representatives are newts and salamanders, which are much rarer and distributed almost exclusively in the northern hemisphere (about 280 species). Finally, the third, smallest order of the legless (Apoda) contains only tropical worms, which are apparently the remains of very ancient armored amphibians that have survived to this day due to specialization in a burrowing lifestyle (about 55 species).

28. Features of the class Amphibians as animals leading a dual lifestyle. Most amphibians spend their lives in wet places, alternating between being on land and in water, but there are some purely aquatic species, as well as species that spend their lives exclusively on trees. Insufficient adaptability of amphibians to living in a terrestrial environment causes drastic changes in their lifestyle due to seasonal changes in living conditions. Amphibians are able to hibernate for a long time under adverse conditions (cold, drought, etc.). In some species, activity can change from nocturnal to diurnal as temperatures drop at night. Amphibians are active only in warm conditions. At a temperature of +7 - +8 ° C, most species fall into a stupor, and at -1 ° C they die. But some amphibians are able to tolerate prolonged freezing, drying out, and also regenerate significant lost parts of the body. Some amphibians, such as the sea toad Bufo marinus can live in salt water. However, most amphibians are found only in fresh water. Therefore, they are absent on most oceanic islands, where conditions are favorable for them in principle, but which they cannot reach on their own.

38. Systematics and features of the subclass Archosaurs. Archosaurs lat. Archosauria are reptiles that are very diverse in appearance, structure, size, lifestyle and habitat. Their common feature is the diapsid type of skull (two temporal windows) and the presence in it of additional eye holes (windows), thecodont teeth that do not have roots and form in separate cells (alveoli). The subclass of archosaurs is divided into four superorders: thecodonts, dinosaurs, pterosaurs and crocodiles. Archosaurs appeared in Perm and exist to this day. Thecodonts existed from the Late Permian to the Triassic, dinosaurs from the Middle Triassic to Cretaceous, pterosaurs from the Late Triassic to Cretaceous, and crocodiles from the Late Triassic to the present day.

31. General characteristics and taxonomy of the subclass Arcuvertebral amphibians. The first subclass of the arcuate (Apsidospondyli) contains 4 orders, bearing the common name of the superorder of labyrinthodonts (Labyrinthodontia). The most ancient detachment of Devonian stegocephalians - ichthyostegs (Ichtyostegalia) - preserved the remains of the gill cover of fish. The labyrinthodonts include the detachment of embolomeric stegocephals (Embolomeri), which was widespread in the Carboniferous period, the Permian rachitomous (Rachitomi), and the stereospondylic stegocephals (Stereospondyli4o), which separated from them in the Triassic. This whole group of labyrinthodonts disappeared at the border of the Jurassic period.

32. The external structure of the frog as a representative of the class of amphibians. The pond frog has a short and wide body, gradually turning into a flat head. The neck is not pronounced. The tail is missing. Above the large mouth are the nostrils, and above them are the bulging eyes. The nostrils have valves that close the access of water to the lungs when the animal is immersed in water. Behind each eye are the organs of hearing, consisting of the inner ear and the middle ear (closed by the eardrum). The body rests on two pairs of dissected limbs. The hind limbs are the most developed. With their help, the frog moves by jumping on land and swims well. Between the fingers of the hind limbs there is a swimming membrane.

33. Features of the internal structure of a frog as a representative of the class of amphibians. The skeleton of amphibians consists of the same main sections as the skeleton of fish. It is based on the skull, spine, bones of free limbs and their belts. Unlike fish, the skull of a frog is movably articulated with the spine, and the ribs are not developed. The main distinguishing features in the structure of the skeleton are associated with the emergence of amphibians on land and with movement on a solid surface with the help of free limbs - front and hind legs. The bones of their belts serve as a support for the skeleton of the fore and hind limbs. In the skeleton of the forelimb, the humerus, bones of the forearm and hand are distinguished. In the skeleton of the hind limb - the femur, the bones of the lower leg and foot. The movable articulation of the bones in the limbs allows the frog to move not only in water, but also on land. The structure of the muscular system in a frog is also more complicated than that of a fish. In connection with movement on land, amphibians develop the muscles of free limbs, especially the hind limbs.

34. Features of the structure of amphibians that arose as adaptations for living on land. Frogs live almost throughout the entire territory of our country, except for the Far North of Siberia and high mountain regions. They live in damp places: in swamps, wet forests, meadows, along the banks of freshwater reservoirs or in water. On land, mostly adults are found, and reproduction, growth, and development of larvae occur in water. The behavior of frogs is largely determined by humidity. In dry weather, some species of frogs hide from the sun, but after sunset or in wet, rainy weather, it is time for them to hunt. Other species live in the water or near the water itself, so they hunt during the day. Frogs are active in the warm season. With the onset of autumn, they leave for the winter. For example, the common frog hibernates at the bottom of non-freezing reservoirs, in the upper reaches of rivers and streams, accumulating in tens and hundreds of individuals, they freeze along with the water, and with the onset of heat they begin an active lifestyle.

35 . Reptiles as the first class of true terrestrial vertebrates. Class REPTILES OR REPTILIA (Reptilia) Compared to amphibians, reptiles represent the next stage in the adaptation of vertebrates to life on land. These are the first true terrestrial vertebrates, characterized by the fact that they reproduce on land with eggs, breathe only with the lungs, their breathing mechanism is of a suction type (by changing the volume of the chest), the conducting airways are well developed, the skin is covered with horny scales or scutes, the skin glands are almost no, in the ventricle of the heart there is an incomplete or complete septum, instead of a common arterial trunk, three independent vessels depart from the heart, the pelvic kidneys (metanephros). In reptiles, mobility increases, which is accompanied by a progressive development of the skeleton and muscles: the position of various parts of the limbs in relation to each other and to the body changes, the limb belts become stronger, the spine is divided into cervical, thoracic, lumbar, sacral and caudal sections, head mobility increases. The skull of reptiles, like that of birds, unlike other vertebrates, is connected to the spine by one (unpaired) condyle. In the skeleton of free limbs, intercarpal (intercarpal) and intertarsal (intertarsal) joints are characteristic. In the girdle of the forelimbs, they have a kind of integumentary bone, the sternum. Now there are about 7,000 species of reptiles, that is, almost three times more than modern amphibians. Reptiles living today are divided into 4 orders: Scaly; Turtles; Crocodiles; Beakheads.

36. General characteristics of the Reptile class. Features of the organization. Reptiles - the first class of real primary terrestrial vertebrates (Amniota). Relatively large, rich in yolk and protein eggs covered with a thick parchment-like shell. Fertilization only internal. Embryonic development goes in the air with the formation of germinal membranes - amnion and serosa - and allantois; the larval stage is absent. A young animal hatched from an egg differs from adults only dimensions.Dry leather reptiles are almost devoid of glands. The outer layers of the epidermis become keratinized; horny scales and scutes form in the skin. Breath only lung. Airways are formed - the trachea and bronchi. Breathing is carried out with movements of the chest. Heart three-chamber. Three blood trunks independently depart from the ventricle divided by an incomplete septum: two aortic arches and a pulmonary artery. The carotid arteries supplying the head arise only from the right aortic arch. The large and small circles of blood circulation are not completely separated, but the degree of their separation is higher than that of amphibians. Selection and water exchange is provided by metanephric (pelvic) kidneys. An increase in the relative size of the head brain, especially due to the increase in the hemispheres and cerebellum. Skeleton completely ossified. The axial skeleton is subdivided into five sections. Elongation of the neck and specialized first two cervical vertebrae (atlas and epistrophe) provide high head mobility. Scull has one occipital condyle and well developed integumentary bones; the formation of temporal pits and the bone temporal arches limiting them is characteristic. limbs ground type with intercarpal and intertarsal articulations. The girdle of the forelimbs is connected to the axial skeleton through the ribs, the pelvic girdle articulates with the transverse processes of the two sacral vertebrae. reptiles populate various ground habitat predominantly in warm, partly in temperate latitudes; some of the species reverted to water lifestyle.

30. General characteristics and taxonomy of the subclass Thin Vertebrates. The second subclass of amphibians - thin vertebrae, or lepospondyli (Lepospondyli) - combines several groups for the most part small stegocephalians (Microsauria), very numerous in the Carboniferous, but already extinct in the Permian period. Recently, lepospondylic stegocephalians are considered the ancestral group for two modern orders of amphibians: caudate (Caudata, or Urodela) and legless (Apoda). However, there is no direct connection between them, since the fossil remains of modern orders were found only in the Cretaceous period, and the lepospondylia died out already in the Permian.

37 . Systematics and features of the subclass Anapsida. Anapsids (lat. Anapsida) are amniotes, whose skull does not have temporal windows. Traditionally, anapsids were considered as a monophyletic taxon of reptiles, however, it was hypothesized that some groups of reptiles with anapsid skulls can only be distantly related to each other. Many modern paleontologists believe that turtles evolved from diapsid reptiles that lost the holes in their cheek bones, although this hypothesis is not shared by everyone. Of the modern anapsids, tortoises are the only living representatives. Turtles were first noted in the Upper Triassic, however, at that time they already had almost all the anatomical features of modern turtles, with the exception of the carapace, that is, their formation should have begun much earlier - in particular, they already had joints inside the rib cage. Most other reptiles with anapsid skulls, including the millerettids, nyctifuretes, and pareiasaurs, died out in the Late Permian in a mass extinction event.

39. Systematics and features of the subclass Scales. scaly(lat. Squamata) - one of the four modern orders of reptiles, including snakes, lizards, as well as lesser-known amphisbaena, or two-legged. Animals of this order are widespread in all parts of the world on the continents and islands; they are absent in the polar and circumpolar regions. The body is covered on top with horny scales, scutes or grains. The quadrate bone is usually movably articulated with the cranium. Of the temporal arches, only one upper one is preserved, or it is also absent. The pterygoids do not articulate with the vomer. The transverse bone is usually present. The teeth are attached to the upper or inner surface of the jaws. The vertebrae are amphicoelous or procoelous. There are two or three sacral vertebrae, if they are expressed. Ribs with one head. The ventral ribs are absent or rudimentary. The pineal opening is present or absent.

40. The external structure of the lizard. Signs associated with the development of land. The body of the lizard is divided into sections: head, trunk, tail, 2 pairs of limbs. The body is covered with dense dry skin with horny scales (there is a molt). The head is oval in shape with large horny shields. On the head are the sense organs, a pair of through nostrils, a mouth with teeth and a long thin tongue. Eyes with movable eyelids. There is a neck. The body is slightly flattened, soft. The tail is long, elastic, can break off and then recover (regenerate). Two pairs of legs are widely spaced on the sides of the body, toes with claws. When moving, lizards crawl - they touch the ground with their bodies.

41. The structure of the circulatory digestive, respiratory and excretory systems of the lizard.The circulatory system of reptiles. Like amphibians, reptiles have two circulations and a three-chambered heart. But unlike amphibians, the ventricle of the reptile heart has a septum that separates it into two parts. One of them receives venous blood, and the other - arterial. Respiratory system reptiles consists of the lungs and airways. The lungs are formed by a large number of cells, so they have a large gas exchange surface. Through the respiratory tract - nasal openings, larynx, trachea, bronchi - air enters the lungs. Digestive system in reptiles (Fig. 39.6) almost the same as in amphibians. However, in the digestion of food in a lizard, not only the substances of the digestive glands are involved, but also beneficial bacteria symbionts. They live in a small outgrowth of the intestine - the caecum. excretory system reptiles consists of the kidneys, ureters and bladder, connected to the cloaca.

42. The structure of the skeleton, nervous system and sensory organs of the lizard. The skeleton of a lizard consists of the same sections as those of amphibians. But in the spine of reptiles, five sections are distinguished: cervical, thoracic, lumbar, sacral and caudal. The first vertebra of the cervical region is connected to the skull so that the lizard can easily turn its head. Like most chordates, the central nervous system of reptiles is represented by the brain (from 5 departments) and the spinal cord. The brain is located inside the skull. A number of important features distinguish the brain of reptiles from the brain of amphibians. Often they talk about the so-called sauropsid type of brain, which is also inherent in birds, in contrast to the ichthyopsid type in fish and amphibians. The olfactory organ is represented by internal nostrils - choanas and vomeronasal organ. Compared to the structure of amphibians, the choanae are located closer to the pharynx, which makes it possible to breathe freely while food is in the mouth. The sense of smell is better developed than that of amphibians, allowing many lizards to find food under the surface of the sand at a depth of up to 6-8 cm. The organ of taste is taste buds located mainly in the throat. The organ of thermal sensitivity is located on the facial fossa between the eye and nose on each side of the head. Especially developed in snakes.

43. The reproductive system of reptiles. Reproduction. The concept of anamnia and amniotes. Reptiles are dioecious animals, bisexual reproduction. male reproductive system consists of a pair of testes that are located on the sides of the lumbar spine. From each testicle departs the seminal canal, which flows into the Wolfian canal. With the appearance of the trunk kidney in reptile wolfs, the canal in males acts only as a vas deferens and is completely absent in females. The Wolffian duct opens into the cloaca to form the seminal vesicle. Reptiles breed on land. Crocodiles, sea snakes and turtles, which are mainly aquatic, are no exception. Fertilization in reptiles is internal. In most species, increased activity is observed during the breeding season: battles of males are not uncommon. Amnion - as an important embryonic adaptation to development in terrestrial life, is formed not only in reptiles, but also in other higher vertebrates in the embryos of birds and mammals. According to the presence or absence of this embryonic organ, all vertebrates can be divided into two groups - into amniotes (Amniota - reptiles, birds and mammals) and anamnia (Anamnia), that is, without an amnion (cyclostomes, fish and amphibians).

44. General characteristics of birds, as animals adapted to flight. Birds are warm-blooded vertebrates adapted to flight, therefore the main features of the external and internal organization of their bodies are associated with flight. This is a streamlined "drop-shaped" body shape, and forelimbs in the form of wings, and a body cover of feathers, and powerful muscles on the chest that provide flight. The purpose of the flight is the thinness and pneumaticity of the bones, as well as the disappearance of the heavy dental apparatus and the development of a horny beak instead; the absence of the rectum and bladder, due to which there is no accumulation of waste products inside the body. With the acquisition of the ability of birds to fly, the whole evolution proceeded in the closest connection with this ability of theirs. Paleontological materials show that the ancestors of birds were primitive archosaurs that lived in the Triassic or even in the Permian period. The ancestors of birds were terrestrial running reptiles and, apparently, medium-sized animals.

46. ​​General taxonomy of birds (up to and including orders). Birds, which include about 8,600 species, are the most species-rich class of vertebrates after fish. However, being extremely diverse in the details of the structure, in terms of the main features of the organization, all birds are very homogeneous. In this respect, birds are the exact opposite of reptiles. This is explained by the fact that reptiles are an ancient, almost extinct class, the main modern groups of which, in the process of evolution, managed to disperse far, while birds are the youngest class of vertebrates, which immediately received a magnificent flowering in the latest era of the history of the Earth. The class of birds is divided into two subclasses: lizard-tailed and fan-tailed.

47. General characteristics and biology of the superorder swimming birds. From a biological point of view, the most characteristic features of birds are, on the one hand, the intensity of metabolism, the intensity of the course of life processes, and on the other hand, movement through the air by flight. These two main features of birds largely determine their biology. It is these properties of birds that fundamentally distinguish them from other groups of vertebrates. Despite the common evolutionary origin of birds and reptiles, the biological differences between these two groups of animals are enormous.

49. General characteristics and systematics of the superorder Keel-breasted.Predatory(lat. Carnivora- "carnivores") - detachment (Pinnipedia).

50. The external structure of a dove. Features of the feather cover . The feather cover is inherent only to birds, which is why they are sometimes called birds. The tightly fitting plumage gives the bird's body a streamlined shape. Feather cover, light and warm, serves as a good thermal insulator, promotes incubation of eggs, and individual feathers (primaries and tail feathers) provide the possibility of flight. In the vast majority of birds, plumage does not completely cover the entire surface of the body. The only exceptions are some flightless birds, whose entire body is evenly covered with feathers. The body of a dove is divided into the same sections as those of reptiles - head, neck,torso and limbs. The pigeon's head is small, rounded, with a fairly long and thin head extended forward. beak, dressed in a horn case. The beak consists of two parts: the upper - mandibles and bottom- mandibles. At the base of the mandible open nostrils. On the sides of the head are round eyes, somewhat lower and back from them under the feathers are hidden ear holes. The pigeon's head sits on a movable neck, which allows the bird not only to deftly collect food and look around, but also clean the feathers of the abdomen, wings, back and tail with its beak. The forelimbs are wings that serve for flight: their planes support the bird in the air.

51. The internal structure of a dove as a flying vertebrate. Features in organ systems. The internal structure of the dove is the same as that of other birds. It consists of: digestive, respiratory and excretory systems. Also present: oral cavity, trachea, crop, esophagus, air sac, stomach, lungs, liver, kidneys, pancreas and cloaca. The stomach of pigeons consists of two sections. In the first of them - glandular- secretion of gastric juice, under the influence of which the food softens. Second department - muscular- has thick walls, food is frayed in it. The bones of the jaws are covered on the outside with horny sheaths that form the beak. The beak is diverse in size and shape, depending on the type of food and methods of obtaining it. There are no teeth, and the food is swallowed whole, but if its volume is very large, then the bird can pinch off pieces with its beak. The esophagus can become very distended.

52. Description of the class Mammals as the most progressive and highly organized. Peculiarities. Mammals are the most highly organized class of vertebrates. They are characterized by a high level of development of the nervous system, primarily the brain. Most mammals have a constant high body temperature. The hair cut usually contributes to the preservation of heat. In almost all mammals, the embryo develops in the womb, which gives birth to live babies. All mammals feed their young with milk produced by the mammary glands of the mother (hence the name of the class of mammals). The combination of many progressive features determined the high level of general organization and allowed mammals to spread widely across the Earth. Terrestrial species predominate among them. In addition, there are flying, semi-aquatic, aquatic and soil inhabitants.

53. The main features of the class mammals. reproduction features. The reproduction of mammals differs significantly from that of other vertebrates. A huge number of animals viviparous. The viviparity observed in some reptiles, amphibians, and even fish differs essentially from that of mammals. Hairline, intrauterine development of the embryo, breastfeeding, care for offspring.

54. General taxonomy of the class Mammals. The class of mammals (Mammalia), containing about 4,000 modern species, is divided into 3 subclasses, which differ greatly in volume. have a cloaca and a number of other reptilian features and have survived to this day only in Australia, the fauna of which is generally distinguished by its antiquity. The marsupial subclass (Metatheria) is a relatively small group, its representatives already have a separate anus and give birth to cubs, but they appear underdeveloped and carry their mother in a bag (hence the name of the subclass). Marsupials also survived to our time only in Australia and in South America, the fauna of which, in its antiquity, occupies the next place after the Australian. Finally, the subclass higher, or placental (Eutheria), includes the vast majority of mammals. They are characterized by the fact that the embryo is equipped with a special organ - the placenta, with the help of which it communicates with the mother's body, and the cubs are born more or less well developed. The placental brain has a significantly higher development.

First animals are a small group of species distributed in the Australian region. According to a number of features, the subclass of the first beasts and the infraclass of cloacae are considered the most archaic and primitive among the infraclasses of mammals. infraclass ( Zaglossus) Barton's prochidna ( Zaglossus bartoni)Bruyne's prochidna ( Zaglossus bruijni) the Attenborough prochidna ( Zaglossus attenboroughi)Zaglossus hacketti Zaglossus robustus family family Steropodontidae.

56. General characteristics, characteristics and distribution of marsupials. Systematics. Marsupials (Marsupialia) - a detachment of viviparous mammals, includes 15–16 families: opossums, predatory marsupials, marsupial anteaters, bandicoots, marsupial moles, climbing marsupials, coenolests, wombats, jumping marsupials (kangaroos), unites more than 250 species. Marsupials have been known in North America since the Lower Cretaceous, apparently descended from panthotheres. In Europe, they existed from the Eocene to the Miocene and were replaced by placental animals. Marsupials are divided today into two superorders with 7 modern orders. Superorder (Marsupialia). A hallmark of placental is the birth in a relatively advanced stage. This is possible due to the presence of the placenta, through which the embryo receives nutrients and antibodies from the mother and gets rid of waste products.

58. The external structure of mammals, on the example of a representative. In the body of mammals, the same sections are distinguished as in other terrestrial vertebrates: head, neck, trunk, tail and two pairs of limbs. The limbs have departments typical of vertebrates: shoulder (thigh), forearm (shin) and hand (foot). The legs are not located on the sides, as in amphibians and reptiles, but under the body. Therefore, the body is raised above the ground. This expands the possibilities in the use of limbs. Among the animals known climbing trees, plantigrade and digitigrade animals, jumping and flying.

59. Progressive features of the internal structure of mammals, system by system. The internal structure of insects- this is a set of features of the structure and location of organs by which representatives of this class differ from other living organisms. Insect organs are located in the body cavity - its internal space, which is divided by level into three sections, or sinus. This separation is possible due to the presence of horizontal partitions (diaphragms) in the cavity. The superior or dorsal diaphragm delimits the pericardial region, inside which is the dorsal vessel (heart and aorta). The lower diaphragm separates the space of the perineural sinus; it contains the ventral nerve cord. Between the diaphragms is the widest visceral (visceral) section, in which the digestive, excretory, reproductive systems and structures of the fat body lie. Elements of the respiratory system are found in all three departments.

1. Type Chordates

Chordates are divided into lower (Cranial and Tunic) and higher (Vertebrates).

Typical signs of chordates:

1) the presence throughout life or 1 of the period of the dorsal string - a chord that acts as an internal axial skeleton. During ontogenesis, it is replaced by the spinal column, which becomes a vertebra.

2) The central nervous system has the form of a tube, its internal cavity is a neurocoel, it is connected by a neuropore to the external environment. The neural tube lies above the chord, is divided into 2 sections - the spinal cord and the brain.

3) the digestive tube - its anterior section - the pharynx - performs 2 functions - digestive and respiratory. The pharynx is pierced by gill slits, in water gills appear in their place, in terrestrial ones, lungs appear as protrusions of the pharyngeal wall.

4) the circulatory system is in the form of a tube, the heart is located on the ventral side under the chord and digestive tube.

Features that unite with invertebrates:

Secondority, is formed by breaking through the wall of the gastrula. In place of the gastropore, a posterior opening is formed.

The secondary cavity of the body - the whole

The presence of metamerism - the segmental arrangement of organ systems

Bilateral, bilateral symmetry

Subtype Cranial

Origin:

According to A.N. Severtsov, the ancestors of the non-cranial were free-swimming, bilaterally symmetrical animals. This group gave rise to two branches. One retained a free-swimming lifestyle and led to vertebrates. The other has adapted to a sedentary, near-bottom or burrowing lifestyle. Subsequently, some non-cranial animals moved to life in the bottom soil, they developed metallural folds and a peribranchial (atrial) cavity (lancelets and epigonichths). The other part remained to live in the water column (amphioxides).

Systematics. Class Cephalothordates

Sem. Brachiostomy- lancelets (European, Asian)

Sem. Amphioxide- signs of larvae are characteristic, 1.5 cm.

Sem. Epigonichthids- differ in asymmetry, small lancelets up to 5 cm.

The body is elongated, laterally compressed. The body is covered with a fin fold, in the back region it is called the dorsal fin, which passes into the caudal fin, then into the caudal fin, metapleural folds pass along the gods of the body, they merge with the caudal folds. The skin of the lancelet consists of 2 layers:

Single layer epidermis (unicellular glands, f mucus - protective)

Thin gelatinous connective tissue - cutis, or corium

Muscular system: 50-80 segments are adjacent to the chord - myomers. The segments are separated by myoseptae (septa).

CNS: There is only a chord in the head. The neurocoel is the rudiment of the ventricle of the brain. In larvae, it communicates with the external environment through the neuropore. In adults, in place of the neuropore - the fossa of Kelliker - the organ of smell. The spinal and abdominal nerves depart from the neural tube.

Digestive system. Breath: The pharynx performs 2 functions - it is an organ of digestion and respiration. The walls of the pharynx are pierced by gill slits. They breathe oxygen dissolved in water. At the bottom of the pharynx there is a groove - endostyle, on which there is a glandular and ciliary epithelium: it secretes a large amount of mucus. The intestines are in the form of a straight tube, ending with an anus.

excretory system: Nefridial. In the anterior part above the pharynx lies about 100 pairs of nephridia (a short strongly curved tube with holes).

Reproduction: Dioecious. There are sex glands. Females have ovaries, males have testes. There are no genital ducts. Mature germ cells enter the atrial cavity through cell ruptures. Fertilization is external, the development of the egg in water.

2. Subtype larval-chordata (tunicates)

Tunicates are a branch of chordates. All typical signs of chordates are developed only in the larval stage. Some species lead a sedentary lifestyle, while others move slowly in the water column. All marine animals feed passively by filtering water flows. Hermaphrodites. Asexual reproduction by budding. The circulatory system is of an open lacunar type.

Ascidia class. 3 Squads:

Neg. solitary sea squirts- gastroascidia or spherical.

Neg. Synascidia, or Colonial- colonies are connected with other bases, united by a common tunic, have independent oral siphons. Fertilization is possible between different colonies.

Neg. Pyrosomats, or Firemen- an ascidian-like zooid is formed from a fertilized egg. there is an oral and cloacal siphon. there is a sole. The body is covered with a tunic.

Tunic layers:

1) hard cuticle outside, under the cuticle - a fibrous network impregnated with tunicin (methane-like substance.

2) two-layer mantle, or musculoskeletal sac: 1. layer - epithelium, skin, two-layer. 2. transverse muscle fibers.

Digestive system, nutrition: Mouth → huge pharynx (gill openings - stigmas; endostyle). The pharynx is a respiratory organ. There is a heart - tubular, the edges are reduced alternately, creating a pendulum-like movement of blood.

Organs of excretion and reproduction: renal vesicles, throughout life there is an accumulation of urea crystals. Sex cells enter the water through the cloacal siphon. They are captured by the oral siphon of another individual. Fertilization is external. A tailed larva is formed, which differs sharply from the adult organism in structure. The larva breaks the egg membranes → goes out into the environment. Swimming 2-3 hours. attached to the substrate → regressive metamorphosis.

Salpa class- floating, sea.

Neg. True salps- colonies exist for a short time.

Neg. kegs- polymorphic colonies

Outwardly, the body resembles a cucumber or a barrel, dressed in muscular ribbons. The entire body is occupied by the atrial and pharyngeal cavities, separated by a dorsal outgrowth. The successive contraction of the muscle bands from the anterior end of the body drives water from the pharynx into the atrial cavity and pushes it out with force → the salpa jerkily moves forward. Salps are characterized by alternation of sexual and asexual reproduction - metagenesis. The asexual salpa develops from the fertilized egg. A kidney stolum is formed on the ventral side of the body, it grows, buds form on the sides, and turns into a chain of daughter individuals. One egg matures in the ovary. Sperm enters the cloacal siphon and fertilizes the egg there. The egg matures in the ovary, breaks the egg shells and comes out. The mother's body dies. The fetus is growing.

Appendicular class- floating. A small oval body from which a tail extends. 1 pair of gill openings. From the base to the tail stretches the chord, neural tube, muscle cords. There is no real tunic. The ectodermal cells of the mantle secrete mucus with a chitin-like substance. With the movement of the tail, the mucus is knocked into a kind of house. Opposite the oral siphon, a lattice of thickened threads of mucus is built. With a blow of the tail, he breaks the house and leaves it. Floats for a while. Builds a new house in 2 hours.

Development and reproduction: In sexually developed individuals, the spermatozoa come out. Eggs mature in the ovary. Sperm enters the ovary, fertilization occurs. An embryo is formed in the eggs, it grows, leaves the mother's body. Comes out. It looks like an adult, differs only in size.

3. Subtype Vertebrate or Cranial

The main features of the organization of vertebrates

Body Shape: In aquatic vertebrates, the body is divided into the head, trunk, and tail. Terrestrials have a variety of body shapes. The cervical region appears, the mobility of the head increases. Unpaired fins are reduced, paired ones turn into limbs. In aquatic limbs, they again turn into fins.

Skin covers: two-layer skin: 1) outer - epidermis, (from ectoderm) 2) inner - corium (dermis) (from mesoderm). Function: protection, metabolism, thermoregulation.

Skeleton: Represented by departments: skull, axial, limb girdles, skeleton of free limbs

Axial skeleton: in the evolutionary series - the chord is replaced by the vertebral column. The spinal column is differentiated, the cervical, thoracic, lumbar, sacral, caudal regions appear.

skull skeleton: The medulla closes the brain. On the sides of the chord, parachordalia are formed, in front of the lateral cartilages and trabeculae. In bony fish, the skull remains cartilaginous, and a shell forms on top. In bony bones, ossification occurs, primary or cartilaginous bones are formed. There are 2 types of brain skull: platybasal - a wide base of the skull, the brain is located between the eyes (fish, amphibians, some reptiles) and tropibasal - the eye sockets are close together, the brain part is behind the eyes (birds, mammals). There are several types of attachment of the brain apparatus to the brain skull:

1) protostyle - the jaw and hyoid arches are suspended from the skull (primitive maxillary)

2) hyostylia - the pendant is attached to the auditory part of the brain skull

3) amphistyly - the upper element of the jaw arch is connected to the skull with the help of special processes (sharks, bone ganoids)

4) autostyly - the upper element of the jaw arch fuses with the skull.

Musculature: Skeletal, smooth, cardiac. Water has a segmental structure (metomeric). With the transition to the ground image, ribbon-like muscles (muscles) are formed. In higher vertebrates, the metomeric structure remains only in the location of the muscles of the spinal column.

CNS: It consists of the brain and spinal cord. The neural tube is differentiated into 2 sections: the head and dorsal. In the anterior part, 3 brain bubbles are formed: anterior, middle, posterior. Further differentiation leads to the formation of 5 departments. From the anterior part of the anterior cerebral bladder, the brain is formed. The back of the anterior cerebral bladder turns into the diencephalon. There are 12 pairs of cranial nerves. Aquatic - 10.

Sense organs: Vision - twin eyes. Organs of hearing: anatomically connected with the organ of balance. In higher, the spiral coiled canal (cochlea) is the organ of hearing. The organs of smell are immersed in the skin. The organs of taste: taste buds are an accumulation of sensitive and supporting cells. In fish on the fins, in others in the mouth.

Digestive system: Starting with the ancient jaws, the oral apparatus is sucking, in modern cyclostomes it is a suction funnel, in fish, a mouth apparatus armed with teeth is being formed. At the bottom of the oral cavity, a tongue with its skeleton (sublingual apparatus) is formed. In the oral mucosa scattered taste buds. The pharynx in aquatic is permeated with gill slits, in terrestrial ones the lungs are connected with it. Pharynx-esophagus-stomach. Sections of the stomach: the cardial part (the esophagus empties), the bottom or fundus part, the pilar intestine (differentiates). Intestines: large intestine, small intestine, rectum. It ends either in the cloaca or the anus.

Respiratory system: Gill slits develop in aquatic animals, gill sacs develop in jawless fish, and gill filaments develop between the gill slits, which together make up the gills. The main function is gas exchange. Amphibians have respiratory organs - lungs.

Circulatory system: Skullless - closed. The heart first appears in cyclostomes as an expansion of the abdominal aorta. First, the heart is 2-chambered. Further 3-chamber (amphibians, reptiles). Starting with amphibians - 2 circles of blood circulation: small and large.

excretory system:

Vertebrate larvae develop a pronephros or pronephros. It is represented by a collection of nephridia. The main element of the kidney is the Malpighian bodies. Amniotes develop pelvic buds (metanephros).

reproductive system: Most are dioecious. The ovaries have a granular structure, the testes are smooth. For anamnia, external fertilization is characteristic, in some internal. Eggs develop only in the aquatic environment. There is a live birth. In amniotes, embryonic membranes appear, the amount of yolk increases. Development is not in the aquatic environment.

4. Section Jawless (class Cyclostomes)

The most ancient primitive vertebrates. They reached their heyday in the Silurian-Devonian. By the end of the Devonian, most of them died out. their remains have not been found. Groups of modern jawless appeared in the Carboniferous.

class cyclostomes

Includes modern jawless. 2 subclasses. The most ancient class. Representatives (lampreys, hagfishes) are characterized by a worm-like shape, bare mucous skin, a mouth opening in the depth of the suction funnel, no jaws, a cartilaginous visceral skeleton, an axial chord covered with a thick mucilaginous membrane - a fatty cushion that covers the spinal cord. Respiratory organs - gill bags (5-16 pairs). They live in the seas and fresh waters. There are unpaired fins.

P / cl. Lampreys

1Neg. Lampreys- 3 groups are distinguished by habitat:

1) Marine or anadromous lampreys- live in the seas. They go to rivers to spawn. Representatives: Atlantic, Caspian.

2) river lamprey- Inhabit coastal areas of the seas. Spawning in rivers. Representatives: European river, Japanese.

3) Impassable river, lake, stream lampreys- small, live in one place all their lives, do not migrate.

P / cl. Mixins– incl. 2 groups

Mixin group- Gill sacs flow into the common subcutaneous canal, which opens outwards with 1 opening.

Bdelostoma group- each gill sac opens outward. 5 to 16 gill sacs.

Unpaired fins. The caudal fin is equal-bladed, there are 2 dorsal fins. In females, an anal fin develops before spawning. The hagfish do not have developed dorsal fins.

covers: the epidermis is multi-layered, numerous skin cells lie in it, secrete abundant mucus (protection).

Skeleton and muscular system: Myochordal complex There is a notochord. The skull is not formed, is at an evolutionary stage, surrounds the brain only from below and from the sides. Visceral skeleton: consists of 3 sections:

a) The skeleton of the preoral funnel - elasticity

b) Gill skeleton - closes the toad sacs

c) Pericardial cartilage - clothes the heart.

The muscular system consists of muscle segments - myomers, separated from each other by partitions - myoseptae.

Digestive organs and nutrition:

Respiration and gas exchange: Respiratory organs - gill sacs. Gas exchange occurs in the capillaries of the walls of the gill sacs.

Respiratory tract: in lampreys: Oral opening → pharynx → breathing tube → internal openings of gill sacs → 7 pairs of gill sacs → external openings of gill sacs on the side walls of the body. At the mixin: Mouth opening → pharynx → independent openings of gill sacs (5-16 pairs) → gill sacs → gill canal opening outwards.

Circulatory system: Closed, 1 circle of blood circulation. There is a 2-chambered heart, 1 atrium and 1 ventricle. Hematopoiesis is carried out in the walls of the esophagus and intestines, in the kidneys, liver.

excretory system: Excretory organs - paired mesonephric (trunk) kidneys located on the dorsal side of the body above the gonads

Reproductive system and reproduction: Separate sexes. The sex glands are paired (ovary or testis), occupy almost the entire abdominal cavity of the body. There are no sexual ducts. Fertilization is external. Lamprey eggs are small. die after spawning and fertilization. They breed once in a lifetime. The larva is a sandworm. After 4-5 years, metamorphosis occurs, the gerbil turns into an adult lamprey. Hagfish have large eggs, development without metamorphosis, a young individual hatches from the egg, differing from the adult only in size. Polycyclic.

Nervous system: The head of the brain is small, lies in the same plane. 5 parts of the brain lie without leaning on each other. The medulla oblongata passes into the spinal cord.

Sense organs: Chemical sense organ: nasohypophyseal sac: Unpaired nostril → nasal passage → olfactory capsule - pituitary outgrowth. Lateral line organ - perception of water currents, registration of the approach of objects. There are weak electrical organs, temperature, tactile receptors and chemoreceptors.

5. Section Jaws. Superclass Pisces. Class Cartilaginous fish

Their earliest fossil remains in the form of scales were found in the Upper Silurian deposits. Representatives of very diverse groups are already found in the Devonian deposits. One of the earliest groups known from the early Silurian are armored fish, their body was covered with a bone shell. They lived until the Carboniferous and then became extinct. Another group were small freshwater acanthodia whose body was covered with bone plates. Actually cartilaginous fish known from the late Silurian - early Devonian. Lamellarbranchs survived two bursts of adaptive radiation - in the Silurian - Devonian and in the early Mesozoic. From the end of the Mesozoic, modern families of this subclass took shape.

External structure: Marine. Torpedo body. paired fins appear: pectoral, ventral. The skin is naked or covered with placoid scales. The function of the axial skeleton is performed by the spinal column. The skull is giostelic. 5-7 pairs of gill slits open on the sides of the body. In whole-headed they are covered by a common gill cover. An arterial cone develops in the heart, and a spiral valve develops in the intestine.

Covers: Fish skin consists of 2 layers:

1) upper - epidermis - multi-layered, it contains a large number of glands that secrete mucus (protective function)

2) corium - the actual skin or dermis - scales are located. The scales consist of plates and a spike lying on it. The main substance is dentin, covered with enamel, the cavity is the pulp, vessels and nerves - such scales are placoid.

Skeleton and muscular system: The skeleton is cartilaginous. The skeleton consists of sections: skull, axial skeleton, free fin skeleton, fin girdle. The axial skeleton is represented by the vertebral column: 2 sections - trunk and tail. The vertebrae are amphicoelous (biconcave). The skull consists of 2 sections - cerebral and visceral. The medulla consists of the olfactory and auditory capsules, the rostrum (snout), and the orbit. Visceral - consists of 3 arches: gill, hyoid, jaw. Musculature consists of myosepts,. A characteristic feature is the autonomy of the muscles - the muscles can contract with a violation of the central nervous system.

Digestion and nutrition: Predators and filtrates. rectal gland (reservoir for the accumulation of salts). Large, three-lobed liver (up to 25% of body weight), source of vitamin A.

Respiratory system: They breathe oxygen. Respiratory organs - gills.

Inhalation-exhalation mechanism: When inhaling, the gill arches diverge to the sides. Water enters the mouth, then into the pharynx, passes into the external gill slits. When you exhale, the gill arches approach each other, water is pushed out.

Circulatory system: The heart consists of a venous sinus, atrium, ventricle, abdominal aorta, it begins with an arterial cone. For the first time, the spleen appears, which lies near the stomach and performs the function of a blood depot, is a hematopoietic organ.

The organs of excretion - the kidneys (trunk), in the form of ribbon-like bodies lie immediately under the spinal column.

reproductive system: Dioecious, fertilization is internal. Males: testes - vas deferens - renal tubules - Wolff canal - cloaca - female reproductive tract. The eggs are large, covered with a horn-like shell.

CNS: Brain - 5 departments: anterior, posterior, oblong, middle, intermediate. The medulla oblongata passes into the spinal cord. 10 cranial nerves leave the brain.

Sense organs: The main receptor is the sense of smell - The olfactory sacs communicate with the external environment through the nostrils. Capable of echolocation - capturing waves reflected from the bottom and objects. Seismosensory organs - lateral line, holes. Ampoules of Lorenzini - allows you to find prey. Eyes with a large crystal, fixed eyelid. Organs of hearing: only the inner ear.

Systematics

The class is divided into 2 subclasses: P/Cl. elasmobranchs and P/Cl. Whole-headed.

1) P/Cl. elasmobranchs

· N/neg. sharks

Neg. Placiformes

Neg. Polygills

Neg. Miscellaneous

Neg. Lamellae:Sem. fox sharks, Sem. Herring, Brownie shark

Neg. Carchariform or sawtooth:Sem. Giant, Sem. Grey, Sem. feline

Neg. Catranoid (spiny) sharks

Neg. Sawtoothed

Neg. Squatinous or sea angels

N/neg. stingrays

Neg. Sawfish (sawfish)

Neg. Rough-like

Neg. Diamond-shaped or diamond-shaped slopes

Neg. Eaglet or stingray:Sem. Orlyaki, Sem. horned rays

Neg. Gnus-like or electric rays

2) P/Cl. Whole-headed- the body is valky, skin ossifications - gill covers are developed. The skull is autostylic. Teeth merge into dental plates. The interbranch septa are reduced. Neg. Chimera The first dorsal fin has a spike. Tail in the form of a tourniquet. Marine. The female lays 1-2 eggs with a filiform appendage.

6. Class Bony fish

General characteristics:

Bone scales develop in the skin. Skull hyostylic or amphistylic (loosely attached to cranial box). The tail is hetero-, homo-diphycercal. 5 pairs of gill slits covered by a common gill cover. A swim bladder is formed. Some have lungs (double breathing), some retain the arterial cone (cross-finned), others are replaced by the aortic bulb. Fertilization is external, in some internal - there is a capulative organ - an outgrowth of the anal fin. Neutral buoyancy - 2 types: open and closed bubble. Functions of the swim bladder: hydrostatic, participation in gas exchange, is a baroreceptor, creation and amplification of sounds.

Covers: Consists of 2 layers:

1) multi-layered epidermis - a large number of glands that secrete mucus

2) corium - cells are colored, called chromatophores - provide a color change under the action of the central nervous system. Scales are protective bony formations in the skin. The crossopterans have cosmoid scales in the form of a bone plate, externally covered with cosmin. Ganoid scales, covered with ganoid, arose from the cosmoid. Ganoid scales can grow together with each other, forming a shell. Normal scales - cycloid - in the area of ​​the lateral line in the scales there are holes that communicate with the lateral line canal.

Digestive system: There is a language. The glands secrete saliva without food enzymes. There is a liver, spleen, gallbladder.

Respiratory system: 2 types of breathing: air and water. Aquatic: oxygen from water - gills. Air - from the air - the swim bladder, lungs, sections of the intestinal mucosa.

Excretory organs, water-salt metabolism: kidneys, gill apparatus, skin, digestive tube, liver. filtering apparatus of the kidneys, many vascular glomeruli - glomerulus

reproductive system: Dioecious. Males have testes, females have ovaries. In crossopterygians, the reproductive and excretory systems are connected, the vas deferens flows into the kidney. The Wolfian canal is the function of the vas deferens and ureter, the Müller canal is the function of the oviduct. care for offspring.

CNS and sensory organs: The brain is divided into 5 sections: anterior (olfactory lobes). Intermediate brain. Midbrain (2 visual lobes). The cerebellum covers the medulla oblongata. Eyes.

SYSTEMATICS:

1. P / class. lobe-finned- scales cosmoid or bone. The notochord persists throughout life. The paired fins are covered with scales. Beaded fin. In the intestines there is a spiral valve, in the heart - an arterial cone. There is a cesspool.

1) N/neg. CrossopterygiansNeg. coelacanths

2) N/neg. Dipnoi Neg. Horn-toothed or one-lung,Neg. Bipulmonary

2. P / class. ray-finned- ganoid or bone scales. There are naked, with shells. Joan is not. The fins are formed by bone rays - lipidotrichia → name. The arterial cone is replaced by the aortic bulb. Instead of light swim bladder.

Cartilaginous ganoids

Neg. sturgeons Sem. Sturgeon Fam. paddlefish

Neg. Polyperiformes

Bone ganoids

Neg. Amieformes

Neg. shell-shaped

3. P / class. bony- bone scales. High degree of ossification. Bone rays supporting the leathery edge of the gill cover are developed. In the heart, instead of an arterial cone, an aortic bulb appears. The swim bladder is devoid of cellularity. The intestine does not have a spiral valve. 1 dorsal fin, the second, if present, without bone rays - fatty.

1 ) N/neg. Clupeoid (herring)

Neg. herring Sem. Herring Sem. Anchovies

Neg. salmon

Neg. cetaceans

Neg. Myctophiformes

2) N/neg. Aravanoid

Neg. Aravaniformes

Neg. beaked

3 ) N/neg. Angveloid

Neg. eels

Neg. Saccular

Neg. Spinosiformes

4) N/neg. Cyprinoids

Neg. Cypriniformes

Neg. Catfish

7) N/neg. percoid

Neg. Sticklebacks

Neg. Cithale-shaped

Neg. Perciformes

Neg. Flatfishes

IN THE OREN. REGION: family of Karpovs (rudd, asp, tench, podust, gudgeon, bleak, crucian carp, carp). from the loach family from the catfish family from the perch family, zander, bersh, perch, from the cod burbot family.

7. Superclass Quadrupeds. Class Amphibians or Amphibians

Class 4 - Amphibians, reptiles, birds, mammals.

Amphibians - anamnia (primary aquatic): 1) the main development in the aquatic environment 3) there is a stage of metamorphosis 4) eggs develop without the formation of embryonic membranes

Origin and evolution. The transition of vertebrates from an aquatic to a terrestrial way of life is accompanied by the appearance of breathing atmospheric oxygen and movement on a solid substrate. In parallel, other organ systems also changed: integument, blood circulation, sensory organs, and the nervous system. The first amphibians that appeared in fresh water at the end of the Devonian are ichthyostegida. They were true transitional forms between lobe-finned fish and amphibians, they had the rudiments of a gill cover, a real fish tail. The skin was covered with small fish scales. However, along with this, they had paired five-fingered limbs of terrestrial vertebrates. Later, in the Carboniferous period, a number of branches arose ( labyrinthodonts). In the Carboniferous, a second branch of primary amphibians also arose - lepospondylus - stegocephalic(shell-headed) for a solid shell of skin bones that covered the cranium. The ancestors of stegocephals were bone fish. They are closest to stegocephals lobe-finned fish. Stegocephalians survived until the beginning of the Mesozoic. Modern detachments of amphibians are formed only at the end of the Mesozoic. intensive speciation of modern amphibians began in the early Mesozoic.

Amphibious class. Adults are characterized by paired limbs with a hinge joint, unequal. The skull is attached to 1 cervical vertebra, an atlas is formed - the occipital joint (the head is mobile). The upper element of the hyoid arch - pendants - turns into the auditory ossicle of the middle ear - the stirrup. The pelvic girdle is connected to the transverse processes of the sacral vertebrae. 2 circles of blood circulation are formed, but they are not completely separated. The lateral line organs disappear in adults. Signs of aquatic animals: 1) the skin is permeable to water 2) trunk (mesonephric) kidneys 3) body temperature depends on the ambient temperature - poikilothermia . Eggs are laid only in water. Larva → metamorphosis → adult.

Leather: Consists of 2 layers: epidermis (multilayered) and corium (thin, with capillaries). The skin is rich in glands that secrete mucus. In those living in dry places, this mucus thickens, forms a film, and reduces moisture loss. The secret can be poisonous (toad, toad). The corium contains pigment cells. The cells of the epidermis become keratinized, claws and nails appear. The legless have bony scales scattered in the corium. Anurans have lymphatic lacunae under the skin - reservoirs that allow, under favorable conditions, to accumulate water reserves.

Muscular and digestive system: The muscles of the limbs increase, the oral cavity becomes more complicated. All adults are carnivorous; larvae can feed on algae and detritus. Prey is captured with the help of the tongue. There is a pancreas, a liver.

Respiratory system: Respiratory function - skin, lungs, mucous membranes of the oropharyngeal cavity. In larvae, this function is performed by the skin, external and internal gills. Breathing mechanism: ventilation of the lungs occurs due to the movement of the bottom of the oropharyngeal cavity.

Circulatory system: The heart is 3-chambered. Blood mixes in the ventricle. Hollow veins appear, they are paired, formed by mixing 3 veins, mixed blood. The bone marrow appears for the first time.

Excretory organs, water-salt metabolism: Larvae have head buds (probuds). During metamorphosis, trunk buds appear. There is a bladder. Decay products: in larvae - ammonia, in adults - urea.

reproductive system: paired sex glands. The function of the oviduct is the Muller canal.

In males: testes → vas deferens → kidney, where they open into the Wolf canal, the lower part of which forms a swelling - the seminal vesicle (reservoir for storing reproductive products). In anurans, fertilization is external (in males, genital calluses are on the paws to hold the female). In caudates - internal. Neoteny - the ability of larvae to sexual reproduction (ambystoma, axolotl) (under unfavorable conditions)

CNS, sense organs: The larvae have lateral line organs. The sense of smell is well developed, there are external nostrils. Jacobson's organs are necessary for the perception of the smell of food in the mouth. The organs of vision are developed in almost everyone. Developed color perception.

Systematics

P / Class Arcuvertebral

N/neg. Jumping

Neg. Primitive anurans

Neg. tailless- flattened body, small limbs, large head. Hind limbs powerful pushing.

Sem. round-language- Protective coloring. Midwife toad - the female lays eggs in the form of cords, the male fertilizes and carries on her paws until hatching.

Sem. pip- Surinamese pipa - the female lays eggs on her back, the male fertilizes and presses into the skin. Cells are formed around the eggs. They stay there until they become frogs.

Sem. spadewort

Sem. toads– Representatives: yeah, leaf frogs. in Russia - gray and green toads. Behind the eyes there are poisonous glands - parotids.

Sem. tree frogs- the tips of the paws are expanded into disks (suckers). Caring for offspring. Representatives: blacksmith tree frog (they build a pool where they lay eggs), marsupial tree frog - on the back of a bag where eggs are laid

Sem. real frogs- Goliath frog, brown, grassy, ​​green frogs

Sem. copepods

P/Class Thin Vertebrates

Neg. Tailed- the body is compressed from the sides, a small head, a tail-balancer, limbs on the sides, small, equal

Sem. Siren- descended from the neotenic larvae of the ambistome. There is no adult stage. There are only forelimbs, external gills are preserved throughout life, there are lungs

Sem. Proteic- Neotenic salamander larvae. There are external gills. Fertilization is internal. Representatives: European, American. Proteus

Sem. real salamanders- gills are reduced, there are ovoviviparous and viviparous

Sem. Tritons- winter on dry land. Representatives: common newt and comb

Sem. Lungless salamanders

Neg. legless- Representative: worms - a worm-like body, a small head. Constrictions divide the body into segments. Limbs and their belts are absent, there is no tail, at the end of the body there is a cloaca. They secrete poisonous mucus. Underground lifestyle, some aquatic. Viviparous.

8. Class Reptiles or Reptiles

Amniotic signs:

1) Embryonic development in the air with the formation of embryonic membranes (serous, amnion, allantois)

2) The eggs are large, covered with a shell

3) Internal fertilization

4) Strengthening care for offspring

5) No larval stage

Origin of reptiles: Terrestrial vertebrates arose in the Devonian. These were armored amphibians, or stegocephalians. They were closely associated with water bodies, since they bred only in water, lived near water bodies, where there was terrestrial vegetation. Rearrangements: adaptations for protecting the body from drying out, for breathing atmospheric oxygen, walking on a solid substrate. All these features took shape in reptiles. Mesozoic reptiles are primarily terrestrial animals. Many of them have adapted to life in the water. Some mastered the air environment. The oldest reptiles are known from the upper Permian deposits of North America, Western Europe, Russia, and China. They are called cotilosaurs. Most of the groups have acquired greater mobility; their skeleton became lighter, but at the same time stronger. The solid shell of the skull has undergone a partial reduction. The present-day crypto-necked and side-necked tortoises to a greater extent preserve the primary appearance of the Triassic land tortoises. Marine and soft-skinned appeared in the late Mesozoic. crocodiles appear at the end of the Triassic. Jurassic crocodiles differ from modern crocodiles in the absence of a true bony palate. The vertebrae were still amphicoelous. Crocodiles of the modern type are descended from ancient archosaurs - pseudosuchians. They are known from the chalk. By the end of the Mesozoic, highly organized birds and mammals were increasingly developed.

Covers. The skin is dry, devoid of glands, breathing is due to the movement of a closed chest (snakes do not have it). The skin is a multilayer epidermis. The upper one is the stratum corneum, the lower one is the Malpighian layer (living, germ). Skin ossifications (plates) lie in the skin. The skin has lost the ability to permeate water and gases. Under the epidermis there is a corium, in the upper layer of which there are pigment cells (coloration).

Skeleton. In the axial skeleton: cervical, thoracic, lumbar, sacral, caudal. In the cervical, the first 2 vertebrae are differentiated (atlas with epistrophy). The lumbar region has short ribs. Capable of autotomy (tail drop).

Circulatory system. An incomplete septum appears in the heart. Mixed blood with a predominance of arterial.

Digestive system: Mostly predators. In the oral cavity there are glands without enzymes. Poisonous ones are converted into poisonous ones. There is a liver, pancreas.

Excretory organs: The kidneys are metanephric, located in the pelvic cavity. 2 types of filtration:

1. those that live in water - a well-developed filtering apparatus (glameruli and nephron). Allocate products into the lumen by filtering the blood plasma. 2. in land animals - the secretory apparatus of the renal tubules is enhanced. The end product of metabolism is uric acid.

reproductive system: Dioecious.

CNS and sensory organs: The brain is enlarged. The olfactory lobes are developed, there is a pituitary gland and an epiphysis. The cerebellum is enlarged. There are 11 pairs of cranial nerves. The organs of hearing are the middle (the stirrup is in it) and the inner ear.

Systematics

1) P / cl. Anapsida (neg. Turtles)

2) P / class. Archosaurs (neg. Crocodiles)

3) P / class. Lepidosaurs (neg. Beakheads, neg. Scaled)

1) P / class Anapsida

Neg. Turtles- Modern ones have a shell consisting of a dorsal shield - a carapace and an abdominal one - a plastron. The carapace is formed by bone plates of skin origin. The ribs and trunk spine are fused with it. The plastron is formed from bone plates. From above, the shell is covered with horny shields. Only the caudal and cervical regions are movable; the rest is fused with the carapace. Jaws without teeth. Well developed lungs. Additional respiratory organs are paired anal bladders and outgrowths of the pharynx. Well developed vision, sense of smell. 5 suborders: P/neg. Hidden neck turtles Sem. freshwater,Sem. Land;P/neg. sea ​​turtles; P/neg. Soft-shelled turtles (soft-skinned); P/neg. Side-necked turtles; P/neg. Turtles

2) P / class. Lepidosaurs

Neg. beakheads- 1 view. Tuatara or Hatteria is the oldest species among modern ones. Up to 70 cm. Island of New Zealand. Protected.

Neg. scaly

P/neg. Chameleons- a keel runs along the back. The limbs are transformed into grasping pincers in the form of 2 opposed groups of fingers. Eyelids fused.

P/neg. lizards – Sem. geckos; Sem. iguanas- sea, wood, land .; Sem. Agamas; Sem. real lizards- viviparous.; Sem. Fusiform; Sem. monitor lizards- the largest, arboreal, terrestrial; Sem. Yadozuby- 2 types. Poisonous; earless monitor lizards.

P/neg. Amphisbaena (two-walkers)

P/neg. snakes- Legless. They are able to open their mouth wide - a movable articulation of the bones of the facial part of the skull. Poisonous ones have poisonous glands and teeth. Belts and limbs are absent. Sem. Slepuns- digging lifestyle; Sem. false-footed; Sem. already shaped;Sem. aspids are mostly poisonous. Sem. sea ​​snakes. Sem. Vipers Sem. pitheads.

P / class Archosaurs

Neg. crocodiles

The body is valky, covered with horny scutes. The nostrils open on the tubercles, the eyes are raised above the surface of the muzzle. On the head and at the anus - odorous glands (mark the territory) lay up to 100 eggs, bury them in the sand. Live up to 180 years. Sem. alligators, Sem. real crocodiles, Sem. gharials– 1 species – Gavialus Ganveticus (Indostan)

9. Bird Class

Origin of birds. P their rarest were ancient lizard reptiles - archosaurs. By the beginning of the Mesozoic (Triassic) - birds. Birds are closest to the squad thecodonts. The evolution of the group proceeded by adapting to climbing trees, in connection with which the hind limbs served to support the body on a solid substrate, and the forelimbs specialized for climbing by grabbing the branches with their fingers. Subsequently, the ability to jump from branch to branch developed. Scales, forelimbs formed feather rudiments of the wing plane. An important stage in the development of birds is the transformation of scales into feathers, which first developed on the wings and tail, and subsequently spread throughout the body. The appearance of feathers not only made it possible to fly, but also played a very important thermal insulation role and determined the homoiothermy of birds. The immediate ancestors of birds have not yet been established. In the last century, in the Jurassic deposits were found and described archeopteryx. There are currently seven known fossil remains of Archeopteryx. Archeopteryxes are characterized by many features of reptiles: the absence of a horny beak, the presence of teeth, a narrow and keelless sternum, and abdominal ribs.

Covers: The skin is thin, dry, devoid of glands. The skin layer is divided into the skin itself - the dermis, blood vessels pass through it, the feathers are strengthened, and muscle fibers are located. The second layer - subcutaneous tissue - a loose layer adjacent to the muscles, accumulates fat reserves. One gland - coccygeal (well developed in waterfowl) - produces a fat-like secret. They lubricate the feather, prevent wetting, a source of vitamin D. The growth of the keratinized layer of the skin forms the horny cover of the beak - ramphoteka. Horny scales cover the fingers, prehensile, part of the lower leg. In some species, males form a bone outgrowth on the flail - a spur.

Pen types, structure: The main feather is contour, consists of a rod, 2 fans on the sides. The part of the trunk to which the fan is attached is called the stem. The lower part is the chin, fixed in a feather bag. Each fan is formed by horny plates - barbs of the 1st order, from which thin barbs of the 2nd order extend, with small hooks located on them. Hooks fastening with each other, form a plate of the fan. Pigments accumulate in feathers - melanins (black, brown color) and lipochromes (red, yellow, green). Contour feathers are fixed in the skin in special fields - pterylia, they alternate with fields where there are no quills of the feather - apterylia. Under the contour feathers - downy (thin rod, beards without hooks).

Propulsion system: The peculiarity of the structure of the neck muscles allows you to turn your head 180 0, owls 270 0. The thoracic vertebrae fuse into the dorsal bone, connect to the sacrum, the trunk is immobile. There is a large sternum with a process - a keel, for attaching the muscles involved in the flight. The tail vertebra turns into a coccygeal bone - a pigastil, the bases of the tail feathers are attached to it. The jaw turns into a beak. The clavicles fuse into a fork - the role of a shock absorber during a wing stroke.

Digestion: In filterers - the tongue is fleshy, in those who feed on nectar - it folds into a tube, in woodpeckers - with hooks. Salivary glands (some have amylase). Some have a goiter - an expansion of the lower part of the esophagus (temporary storage of food when the stomach is full; in pigeons, the cells of the goiter undergo fatty degeneration - bird's milk).

Breath: Through the nostrils, air enters the nasal cavity → choanae → oral cavity. There are 2 larynxes - the upper one (does not have vocal cords), behind which is the trachea, and the lower one (forms the vocal apparatus). Sounds are generated by vibrations as air passes through the eardrums.

Inhalation-exhalation is carried out due to the movement of the chest. Oxygen saturation occurs continuously during inhalation and exhalation (double breathing).

Isolation, water-salt exchange: kidneys → ureters → cloaca. The metabolic product is uric acid. A loop-like section appears in the nephron - the loop of Henle (water readsorption) - allows you to remove harmful substances.

reproductive system: In females: only 1 left ovary develops. Fertilization in the upper part of the oviduct. Holases (cords) - the dense part in the egg - allows the yolk to spin, the germinal disc will always be on top. The smaller the bird, the larger the clutch. Sexual dimorphism is pronounced.

Nervous system, sense organs: 12 pairs of cranial nerves. The main receptor is vision. Color vision. Recognize sweet, bitter, salty. Thermoreceptors, touch receptors.

Systematics:

Aquatic, near-water birds

N/neg. floating

Neg. penguins Neg. loons Neg. Toadstools.Neg. Petrel-like (Tube-nosed) Neg. Pelicans (Copepods) Neg. Storks (Archives) Sem. Herons, Storks, Ibises, Flamingos . Neg. Anseriformes

Birds of open landscapes

Neg. ostriches Neg. Nandu-shaped Neg. cassowaries Neg. Kiviformes (Wingless) Neg. Falconiformes P/neg. Amer. Vultures P/neg. falconsSem. Hawks, Falcons. Neg. Galliformes Neg. Cranes Sem. Real Cranes, Bustards Neg. Pigeons Neg. parrots Neg. cuckoo Neg. Owls Neg. Swift-shaped P/neg. Swifts P/neg. hummingbird Neg. Woodpeckers P/neg. Primitive woodpeckers P/neg. real woodpeckers Neg. passeriformes P/neg. Hornbeaks P/neg. Screaming P/neg. passerines Sem. Larks Sem. swallowtail Sem. crows Sem. Blue fam. Thrush Sem. Wagtail Sem. Starlings Sem. finches

10. Class Mammals or Animals

The progressive evolution of mammals has been associated with the acquisition of: high body temperature, the ability to thermoregulate, a high aerobic metabolic rate. This was facilitated by changes in the respiratory and circulatory systems: this was expressed in the division of the heart into four chambers and in the preservation of one aortic arch, which led to the immiscibility of arterial and venous blood, in the appearance of a secondary bone palate, which provided breathing during meals, accelerated digestion of food. changes in the structure of the jaws, differentiation of teeth, development of the jaw muscles. The animal-toothed reptiles closest to mammals were cynodonts. The most pronounced features of skeletal changes were found among them in thrinaxodon from the early Triassic. In the subsequent development of mammals, paleontologists emphasize changes in the dental system. This led to the separation of two groups - morganucodonthod and Cuneotheriidae→Eupantotherium. Biologically, they were to a certain extent close to terrestrial and arboreal insectivores. At the end of the Mesozoic, the division into two independent stems - Inferior, marsupials, and higher, placental. The oldest group of marsupials is the opossum family.

Placental mammals arose in the Cretaceous period. Fossil monkeys have been known since the Paleocene. tree monkeys - propliopithecus- gave rise to gibbons and close to anthropoids, Ramapithecus. Of great interest are australopithecuses. The class of mammals is of pyphyletic origin, i.e. its individual branches arose from different groups of animal-like reptiles. Modern mammals are divided into:

1) First passers (first beasts)

2) Real mammals (animals)

There are egg-laying mammals.

Covers: 1) Epidermis (multilayer, keratinized) → dermis → fiber. The epidermis is the lower layer of cells, they become keratinized and rejected (dandruff). Derivatives of the epidermis - hair, nails, etc. in the epidermis there is a pigment - melanin (coloring, tanning, protection from sunlight). 2) Corium (skin itself) - formed by fibrous tissue, rich in blood vessels. The lower layer of the corium is subcutaneous fat.

2 types of hair: outer (long, hard) and down (soft). The outer hair consists of a trunk protruding outward and the base of the bulb, reinforced in the dermis. Glands (derivatives of the epidermis): sebaceous - their ducts open into the hair bag. The secret lubricates the skin, hair; sweat - open anywhere on the surface of the skin (thermoregulation). A modification of the sweat glands is the mammary gland. There are sensitive hairs - virbis (touch), the root of which is in the blood gap.

Skeleton, muscular system: The number of bones increases. Axial skeleton - cervical, thoracic, lumbar, sacral, caudal. All have 7 cervical vertebrae. The thoracic region is a closed chest. There are false edges (do not connect). The skull has a zygomatic arch. Limb belt - scapula, clavicle. Free department - shoulder, forearm, hand. Belt of the pelvic limbs - pelvis (closed - fused with the help of bone fusion - symphysis), thigh, lower leg, foot.

Digestive system Oral apparatus - lips, teeth, tongue, cheeks, gums. Heterodontism (raznozubnost) - incisors, canines, small and large molars. Salivary glands - enzymes (amylase), a bactericidal substance (lysozyme), stomach - single-chamber (carnivores) and multi-chamber (herbivores), consists of departments - scar, mesh, book, abomasum.

Respiratory system: Breathing due to the movement of the chest. Oral or nasal cavity → larynx → trachea → lungs (ending in alveoli). 2 types of breathing - abdominal (predominant in herbivores) and chest (predominant in carnivores).

Circulatory system: 4-chambered heart, 2 atria, 2 ventricles.

Excretory organs: The kidneys are pelvic, metanephric (in the pelvic cavity). Consist of 2 layers - cortex and medulla. The unit of the kidney is the nephron. Metabolic products - urea.

reproductive system: In males: the testicles are placed in the scrotum. Around the testicles is the appendage of the testis (maturation of germ cells), from which the vas deferens opens on the seminal mound at the root of the penis. In females: paired ovaries → oviducts open next to the uterus. Types of uterus: double (2 bodies, 2 horns, 2 vaginas; in rodents), bicornuate (dogs, pigs), simple (in primates, humans), bifid. The cervix opens into the vagina. The ovaries mature in the follicle - Graf's vesicle. The egg enters the abdominal genital funnel. Fertilization occurs in the upper part of the oviduct.

Systematics

P / class Cloacae (first beasts) - The most primitive. They lay eggs and incubate them. Neg. single passSem. Yachidna- the body is covered with needles, have a beak. Sem. Platypuses- semi-aquatic, between the fingers of the membrane. They filter the water.

P/class Animals

N/neg. marsupials

Neg. marsupials- Babies are born prematurely, carried out in a pouch. There are mammary glands in the bag. Sem. opossums, Sem. carnivorous marsupials, Sem. Marsupial badgers (bandicoots), Fam. Couscous- herbivores, Sem. Kangaroo

N/neg. Higher Beasts (Placental)- capable of sucking milk

Neg. Insectivores Sem. Hedgehogs- in Orenb. Region - eared and ordinary hedgehogs, omnivores, Sem. Moles, Sem. shrews- the smallest - a tiny baby shrew (2-3 g)

Neg. Woolly wings (kaguans) Neg. Bats– echolocation, active at night

P/neg. fruit bats

P/neg. The bats They feed on blood, nectar, insects Sem. bagwings, Sem. fish-eating, Sem. False vampires, Sem. Vampires, Sem. common bats

Neg. edentulous- characterized by underdevelopment of teeth. Sem. Anteaters,Sem. armadillos

Neg. Lagomorphs Sem. pikas, Sem. Hares

Neg. rodents Sem. beaver, Sem. squirrels, Sem. jerboas, Sem. Mouse, Sem. Hamsters, Sem. Agouti, Sem. Chinchilla

Neg. cetaceans- forelimbs - flippers, hind limbs are absent.

P/neg. baleen whales Sem. Smooth (real) whales, Sem. Gray whales, Sem. Stripes

P/neg. toothed whales-there are teeth (homogeneous). Sem. river dolphins, Sem. Sperm Whales, Sem. Dolphins

Neg. PredatorySem. Doggystyle, Sem. Raccoons, Sem. Bears, Sem. Cats, Sem. Hyenas

Neg. pinnipeds Sem. eared seals, Sem. real seals, Sem. walruses

Neg. Odd-toed ungulates- the phalanges of the fingers end in a hoof. Sem. Tapirs, Sem. Rhinos

Neg. artiodactyls- an even number of fingers

P/neg. Non-ruminants- simple stomach, 4-fingered limbs Sem. Pigs,Sem. Bakers,Sem. hippos

P/neg. Ruminants- The stomach is complex. Belching food - chewing gum. Sem. musk deer, Sem. deer, Sem. giraffes

P/neg. calluses- limbs have 2 fingers, devoid of hooves Sem. camels

Neg. Primates- 5-toed, plantigrade. 1 finger is opposed to the rest. Odd-toothed. Big brain, convolutions appear

P/neg. Lower primates (semi-monkeys)Sem. Tupai- primitive, woody Sem. Lemurs, Sem. Lori– arboreal, tropics

P/neg. Greater primates (monkeys) Section of broad-nosed monkeys: small marmosets, callimico and major capuchin monkey. Narrow-nosed section: Sem. Monkeys,Sem. Gibbon, Sem. hominids