Reptiles: snakes, lizards, geckos, turtles, turtles, crocodiles, etc. It belongs to Vertebrate subfamily. Their body structure and physiological function are more suitable for the living environment on land than amphibians. The body has been clearly divided into head, neck, trunk, limbs and tail. The neck is developed and can rotate flexibly, which increases the predation ability and can give full play to the functions of sensory organs such as head and eyes. Developed bones provide conditions for supporting the body, protecting internal organs and enhancing sports ability. Breathing with the lungs, the heart consists of two ears and two chambers that are not completely separated, and gradually evolves in the direction of separation of arterial blood and venous blood. Compared with amphibians, the brain structure has been further developed, and the sensory organs have also increased complexity and function. During the reproductive development of reptiles, some changes will take place in the structure of eggs and embryonic development. The egg is covered with a hard calcareous shell, which can prevent the evaporation of water in the egg and fertilize in vivo, and get rid of the dependence on water during fertilization in reproductive development. Amniotic membrane and amniotic fluid appear in embryonic development, and embryos can develop in amniotic fluid, which can prevent dryness and mechanical damage. Reptiles flourished in Mesozoic, almost all over the world, and dinosaurs were the representatives at that time. Later, due to changes in climate and crust, most species became extinct. There are more than 5,000 species, including lizards, snakes, turtles, soft-shelled turtles and crocodiles. Reptiles are amniotic animals, covered with horny scales or hard armor, which breed on land. They not only inherited the characteristics of amphibians' initial landing, but also made further progress in preventing water evaporation, adapting to land life and reproduction. Reptiles are real terrestrial vertebrates, and ancient reptiles are also the evolutionary ancestors of higher-level thermostatic amniotic animals such as birds and animals. Therefore, this kind of animals is of great significance in the evolution of vertebrates. In geological history, reptiles flourished in Mesozoic, with great variety and quantity, and declined at the end of Mesozoic. The existing species only include crocodiles, turtles, lizards and snakes. Among them, the largest individual is the Python reticulatus, which is produced in Southeast Asia, with a total length of 9.9 m, while the smallest lizard is the Sphaerodactylus argus, with a total length of only 36 mm ... Except the Antarctic region, it is almost distributed all over the world, especially in the southern hemisphere, and can inhabit plains, mountains, forests, grasslands and deserts. The highest vertical distribution point of a few lizards (Tibetan sand lizard and red-tailed lizard) can reach the cold desert area of Qinghai-Tibet Plateau above 5000 meters above sea level. This reptile is really out of water. Reptiles are a kind of warm amniotic animals, covered with scales or hard armor, which breed on land. Reptiles evolved from ancient amphibians at the end of Carboniferous, and are the highest temperature-changing vertebrates that really adapt to land life. Birds: eagles, sparrows, pigeons and bedbugs are characterized by feathers on their bodies. Birds' feathers are different from those of mammals. Mammals have one hair, while birds have one feather. Birds reproduce their offspring with eggs. Most birds are good at flying, but a few birds are not good at flying, or even can't fly. As long as it conforms to the characteristics of birds, no matter whether it can fly or not, no matter what environment it lives in, it is a bird. Their morphological structure adapts to flying life and has the following characteristics: ① Their bodies are hammer-shaped. 2 The whole body is covered with feathers, and the down is born under normal feathers, keeping the body temperature constant and the body temperature is as high as 42℃. (3) hollow bone to lose weight. (4) Toothless, horny beak. ⑤ The large intestine is extremely short, without bladder, and feces are discharged from cloaca at any time. ⑥ Airbags and lungs, double breathing. Most birds nest, hatch and brood. The breeding of birds has obvious seasonality, generally in spring and early summer. Most birds breed one nest every year, and a few birds breed several nests. Feathers of birds can be divided into normal feathers, down feathers and fine feathers. Birds' feathers change regularly, which is called molting. Most birds' feathers fall off and are replaced in autumn. The new feathers after replacement are called winter feathers, and some or all feathers are replaced in the next spring. The replaced feather is called Stephane. The colors of Dong Yu and Xia Yu are often different. The replacement of flying feathers and tail feathers is generally symmetrical, that is, the long new feathers in pairs fall off, so that the flight can not be affected when molting. Mammals: rabbits, dogs, cats and rats are characterized by further development of intelligence and sensory ability; Maintain a constant temperature; Improve reproductive efficiency; Enhance the ability to obtain food and handle food; There are hairs and viviparous on the body surface, which are generally divided into five parts: neck, trunk, limbs and tail; Breathe with the lungs; A warm-blooded animal with a constant body temperature; The brain is big and developed. Breastfeeding and viviparous are the most striking features of mammals. The embryo develops in the mother, and the mother beast directly gives birth to the fetus. All females have mammary glands, which can secrete milk to feed their young. All this involves the structural changes of various parts of the body, including the increase of brain capacity and the appearance of new brain skin, the highly developed vision and smell, and the specialization of hearing is greater than that of other vertebrates; The specialization of teeth and digestive system is beneficial to the effective use of food; The specialization of limbs enhances mobility. Help get food and escape from the enemy; The perfect respiratory and circulatory system and unique fur cover help to maintain their constant body temperature, thus ensuring their survival in a wide range of environmental conditions. Viviparous, breastfeeding and other unique characteristics ensure their offspring have a higher survival rate and the development of some complex social behaviors. Insects: grasshoppers, aphids, newts, dragonflies, butterflies, moths, mantises, owls, cicadas, flies, bees and wasps: bumblebees, wheat bees, stingless bees, wall bees and leaf-cutting bees. Bees refer to all flying social insects in the family Apidae, which feed on pollen and nectar and brew honey. Its cell deposition is also the only eukaryote with iron mineral deposition in cells. There are three kinds of bees in the bee colony: queen bee, worker bee and drone. There is a queen bee (there are two queens in some special cases), 1, 000 to 1, 500 worker bees, 500 to 1, 500 drones. Bees originated in Asia and Europe and were brought to America by British and Spanish. In order to get food, bees keep working, collecting honey during the day, making honey at night and pollinating fruit trees, which is an important medium for crop pollination. Poultry animals: dogs, cats, chickens, ducks, geese, pigeons, quails, cormorants. Most real ducks (including several birds that are mistakenly called geese because of their individual size and body shape) are different from swans and geese and have the following characteristics: males shed their skins twice a year; Females lay more eggs in each nest and the eggshells are smooth; The legs of both sexes are covered with overlapping scales; The call and feathers show some gender differences. All real ducks, except the snub-nosed duck and the sea duck, are sexually mature in the first year and are paired in the breeding season, unlike swans and geese, which mature late and pair for life. According to the unique behavior of ducks, ducks can be divided into three categories: drilling ducks, diving ducks and perching ducks. The mallard duck is a typical duck and the ancestor of most domestic ducks. Habitat ducks, such as Moscow ducks, have long claws and are favorite arboreal ducks. Diving ducks include most marine species. The mallard flies from the south to the north to lay eggs in spring, and then flies to the south for winter in autumn. After they were domesticated by humans, they lost their frivolous migration. In order to get more duck eggs, they were not allowed to stop production and hatch. Over time, domestic ducks lose the ability to hatch eggs. Duck's eyes have a 360-degree field of vision, and you can see behind you without turning your head. Fish animals: carp, grass carp, shark, tropical fish, sardines and daffodils. They live in water all their lives, breathe through gills, and use fins to help balance and exercise. About 2000 species have been proved, which is the most primitive and lowest group of vertebrates. Fish is rich in animal protein and phosphorus, rich in nutrition and delicious. It is easily digested and absorbed by human body and plays an important role in the development of human physical strength and intelligence. Other parts of fish can be made into cod liver oil, fish glue, fish powder and so on. Some fish, such as goldfish and tropical fish, are brightly colored and have high ornamental value. Fishing is a healthy sport and is loved by people all over the world. In addition, some fish, such as mosquito-eating fish, are beneficial to human health by eliminating malaria, yellow fever and other infectious pathogens. Classified fish are generally divided into two categories: jawless and jawed. The jawless spine is cylindrical and exists for life, without mandible. Branches originating from endoderm are cystic, so they are also called cystic gills. The brain is developed, generally with 10 pairs of cranial nerves; Pairs of visual and auditory devices. The inner ear has 1 or 2 semicircular canals. Have a heart, blood red; The epidermis consists of multiple layers of cells. The lateral fins are underdeveloped, and some ancient fish have pectoral fins. Jaws have different classifications, generally divided into: blind eels, head turtles, lampreys, and fin turtles. The jaw has an upper jaw and a lower jaw. Most of them have pectoral fins and ventral fins; The endoskeleton is developed, the adult notochord degenerates, there are spines, and there are few exoskeletons. The inner ear has three semicircular canals. Gills are formed by ectodermal tissue. It consists of shield fish, cartilaginous fish, spinosaurus and bony fish. Among them, there are only fossil species in shield fish and spinosaurus. It is distributed all over the world, mainly inhabiting low-latitude seas, and a few species inhabiting fresh water. The existing species belong to Claudiobranchia and Cephalopoda. There are about 600 species of Claudiobranchia, and about 180 species in China, most of which are distributed in the South China Sea. There are about 30 species of Cephalopods in 3 families, 6 genera and 5 species in 2 families, 3 genera in China. The endoskeleton of teleost is ossified, with bony seams, and the head is often covered with membranous bone, while the body is covered with hard scales or bony scales. It is the most luxuriant branch of existing fish, which can be divided into three subclasses: total fin, lungfish and radial fin. Kiwifruit is the largest group. Among them, Perciformes have the most species, except Cypriniformes, which are mostly anadromous fish, and other orders are mainly distributed in the ocean. In today's world fishery production, the output of herring and cod is the highest, followed by cod, which is close to half of the total world fishery output that year. There are more than 2,000 species of teleost in the offshore of China, and more than 700 species of freshwater teleost. Body structure and life activities of fish Although fish is the lowest vertebrate, it already has quite complete organ systems such as bones, muscles, digestion, circulation, respiration, excretion, reproduction and nerve sensation, and can carry out extremely diverse life activities. Its morphological structure is not only related to systematic development, but also reflects its adaptability to water environment. The adaptability of the external shape and body shape of swimming fish to their living environment is mainly manifested in the following aspects: fish living in the upper water body are generally spindle-shaped, fish living on the bottom of the sea are flat, coral fish are mostly flat, and secluded fish are cylindrical. Some fish living in seaweed are mimicry, while tuna are torpedoes, which are suitable for fast swimming. The movement of fish mainly depends on the alternating contraction of muscles arranged on both sides of the body, so that the body and tail fin swing forward from side to side, while other fins play a role in balance and steering. After metamorphosis, some fins also have the functions of attack, self-defense, feeding, reproduction, vocalization, crawling, sliding, jumping, climbing and breathing. The swim bladder can adjust the proportion of fish and help it float and sink. The skin, scales and skin of body color fish include epidermis and dermis. The epidermis consists of several layers of living cells, in which mucus cells are distributed to reduce friction and protect the body. Zhu Xing is the product of keratinization of local epidermal cells, which is related to reproductive activities. The poison glands and luminous bodies of some fish are derivatives of epidermis. Fish scales are divided into shield scales, hard scales and bone scales. The scales of cartilaginous fish are called shield scales. Hard scales and bony scales are usually produced by dermis. The fish scales are arranged horizontally, which is convenient for the fish to move and protect. Many fast-swimming hermit fish often lose their scales or disappear. The body color of fish is often deep in the back and shallow in the abdomen, which is a protective color suitable for the environment. However, fish living in coral reefs are often brightly colored and striped, which are generally divided into protective colors and warning colors. Skeletal and muscular fish have developed central axis and appendage bones, which play an important role in protecting the central nervous system, sensory organs and internal organs, supporting body drive and whole body activities. The axial skeleton consists of skull (chest skull and pharynx skull) and spine. The pharyngeal cranium is a group of bones around the front end of the digestive tract, which is used to support the mouth and cheeks. The spine consists of many vertebrae. The smooth muscle and myocardium of fish are not much different from those of higher animals, but the striated muscle is obviously segmented and divided into sarcomere and branchial muscle. The muscles of the trunk are arranged in an arch according to the joints. The feeding and digestive habits of fish are usually divided into four types. Filter feeding, such as silver carp, bighead carp, sardines and other plankton; Herbivores, typical grass carp; Carnivorous, such as snakehead, pike, snakehead, hairtail and herring. Omnivorous, such as carp. Carnivores: Tigers, leopards, lions, hunting dogs and cats can be roughly divided into two categories: carnivores weighing less than/kloc-0.5 kg to 20 kg and carnivores weighing more than/kloc-0.5 kg to 20 kg. The former generally feeds on rodents, insects and animals lighter than them, while the latter targets animals of the same or larger size. However, hunting these large animals will consume a lot of energy. After roughly estimating the size of carnivores, the researchers believe that they spend twice as much energy hunting large animals as hunting small animals. In addition, the researchers also noticed that it seems that it is difficult for the largest carnivores to get enough food no matter which of the two sets of predation methods is used. The largest carnivores, such as lions and polar bears, spend most of their time resting or moving slowly to conserve their strength, and their overall energy intake and expenditure ratio is usually lower than their estimated size. Small carnivores can adopt the strategy of "high cost and high reward" to prey on large prey, and their bodies can still become stronger, but large carnivores have no "high cost and high reward" strategy to choose from. Based on this, Capogni's research team speculated that once the weight of carnivores exceeds 1 1,000 kg, their viability will be severely tested. That's true. For example, the largest extinct carnivore, the short-faced bear, weighs 800 kg to 1000 kg, while the average weight of the largest carnivore in existence, the polar bear, is even smaller. The researchers pointed out that even a large carnivorous dinosaur like Tyrannosaurus Rex needed about the same energy as a mammal weighing 1 1,000 kg. However, this threshold may be quite different in the ocean. The higher productivity of the ocean means that large marine animals can fill their stomachs effortlessly. James brown, an ecologist at the University of New Mexico, said that the benefits of the ocean can make large carnivorous mammals such as whales bigger and bigger. I'm exhausted. I've been looking for it for three hours. . Enjoy your meal, landlord.