Are there any articles about the process of tadpoles becoming frogs?

Physiological characteristics and life characteristics of frogs The larvae of frogs are called tadpoles, which are fish-like and have external gills. They are suitable for living in water. They scrape algae with horny teeth on their lips, then gradually grow limbs, their tails slowly shrink and their gills disappear. They use lungs instead of breathing, and they have an adult form to live on land. However, the lungs are not developed enough, and they also rely on skin breathing for initial help. Frog's skin is bare without scales and rich in glands. The secretion of mucus glands often keeps the skin moist, which is beneficial to breathing. Frogs like to live in rice fields, ponds, ditches and river banks. Their staple food is to catch moving insects. Whether it's flying insects, jumping insects, corn borers hiding in curved leaves, cotton bollworms hiding in cotton peaches, grubs hiding in underground caves, and earth tigers, as soon as they come out and get close to frogs, they jump up, open their mouths, stick out their long tongues, stick to insects and get involved in their mouths. Frog's metabolism level is low, it can't produce enough heat by itself, and it doesn't have a perfect thermoregulation mechanism, so it can't maintain a constant body temperature, so it is greatly influenced by environmental temperature changes. Every year in the middle of June, 5438+065438+ 10, choose loose riverbanks or vegetable garden soil, crevices and tree roots for hibernation. In March and April next year, when the temperature rises above 10℃, it will begin to wake up and come out to move. In hot summer, sometimes there will be summer sleep. The frog's own "defense" ability is weak, and almost only passively avoids or secretes protective color, warning color or glandular fluid to protect itself. For example, a female frog that is black in spring turns black and gray in May-June and light gray in July. After August, the skin color begins to deepen, and it will deepen when the light is dark on cloudy days. Frogs live in a humid, cool, quiet and clean environment. If it is dry, it will cause a lot of water loss in its body, leading to dehydration and death. Third, the design of frog breeding pond can be determined according to the specific situation. There are two common types: 1. Raising frogs in paddy fields requires sufficient water, convenient irrigation and drainage, strong water retention and poor fertility. There should be fences around, and the inner wall of the wall should be smooth to prevent frogs from escaping. The water depth is 10-20cm, and grids are set at the entrance and exit of paddy fields to prevent tadpoles from escaping. In addition, an incubator was set up in the field, and a net was set on the incubator to prevent the enemy from destroying it from the air. 2. Design of large-scale farms The aquaculture pond should be built in a place with sufficient water, convenient irrigation and drainage, clean water quality, suitable water temperature and no pollution. The fence of the aquaculture pond can be made of net, cement board, plastic board or brick. The base of the outer fence is buried about 15-20cm underground, and the inner side of the wall needs a layer of nylon net to prevent frogs from being injured, and it also has a defensive effect against foreign snakes and rats. The upper part of the breeding sound should be enclosed with a net to prevent birds from invading. Mud is generally suitable for the bottom of the pool, which is convenient for frogs to bury for the winter. Large-scale aquaculture ponds should build spawning ponds, hatching ponds, tadpole ponds and adult frog ponds according to the needs of different development stages of frogs. Oviposition pond: there are two kinds: central pond and ditch pond. The walls of the central spawning pond can be made of cement boards, nets or bricks. 90 cm high, located in the center of the large pool, the area depends on the needs. The land area accounts for one third, and shelters such as boards or straws are placed on it, and flowers or vines are planted to provide shade. A 50-square-meter spawning pond can hold 35-40 kilograms of frogs. The gully pond is an indirect spawning pond with a width of 8.4m, a length of 10m and a height of1.1m.. Dig parallel ditches in the pond, with the ditch spacing of 120cm, and drain water in the ditch, with the water depth of 10- 15cm. Place a shielding plate every 30 cm on the boundary. The board is 9 cm high, 70 cm long and 70 cm wide. It is covered with straw to make it dark and cool. Dig a shallow ditch on the ground below the edge of the board to let frogs enter the habitat. Both the central spawning pond and the ditch spawning pond are laid with detailed nets. After laying eggs, the net is hoisted together with the eggs and moved to an incubator for incubation. Incubation pond: In order to facilitate observation of tadpoles, it is best to use a brick cement pond with a height of 40 cm, a width of 120 cm, and a length of about 300 cm. It is also equipped with a water injection port and a drain port to facilitate water injection and drainage, and to control water temperature and water level. Set up a shed by the pool to prevent direct sunlight at noon. The water in the incubator should be cleaned and disinfected to improve the hatching rate and reduce diseases. Tadpole pond: brick or mud-digging pond can be used. Brick tadpole ponds are generally 60 cm high, 0/20 cm wide, 400 cm long and 20-25 cm deep. Covering the mud with black plastic sheets to clean the bottom of the pond can absorb sunlight, raise the water temperature and promote the growth of tadpoles. The tadpole pond can also be a rectangular cement floor, with the wall surface leveled with cement and mud left at the bottom. The pool wall has a certain inclination and drainage holes, and the water depth is 50 cm. There are water hyacinths in it, and bamboo foil is used to guard against the enemy. When tadpoles are deformed, they are put into cloth bags or frog collection boxes for deformed young frogs to live in the shade. When grasping, slowly pull the box out of the water with a hand net. The frog box is 5cm high, 20cm long and 20cm wide. Just use two thin boards and nails between their four corners, and leave the other four sides blank. Adult frog pond: In order to facilitate separate feeding, feeding and catching, prevent disease infection and control density, adult frog pond should not be too large. Although frogs like to live by water, they don't often live in water, so there shouldn't be too much water in the pool, so more land should be set aside as a habitat. The pond should be rectangular with 3-4 water injection and drainage ditches. For example, a field with a length of 16m, a width of 8m and a height of 90cm. The pool is made into a ridge with a width of 150 cm, a width of 70 cm and a water depth of 10- 15 cm. On the land on both sides of the wall, place a wooden board or three plywood boards at intervals of 10-20 cm, with the length and width of 65438 respectively. The height of the mat under the board is 3.5 cm, which is beneficial to the habitat of frogs. The purpose of placing wooden boards is to create an ecological environment for frogs, avoid external human and animal interference, and keep them cool, windproof and rainproof. The board can be adjusted according to the growth of frogs. So the number and size of frogs hiding under the board are similar. It is convenient to control the feeding position and adjust the feeding amount. The land in the site should be practical and maintain good water injection and drainage functions. The screen should be filled with water and drainage holes to prevent the enemy from invading and the frog from escaping. The area and stocking quantity of frog pond should be determined according to the overall size and water supply in each period. Generally speaking, there are 5000-7000 frog eggs per square meter, tadpoles 1000-2000, 70- 100 young frogs (within 40 days 100, 70 over 40 days) and 20-30 adult frogs. Four. Breeding technology of frog 1. Selection of Breeding Frog The breeding frog that lays eggs for the second time has a higher fertilization rate. Although the female frogs in the third and fourth years lay a large amount of eggs, the fertilization rate is poor and the hatching rate in the first year is also low, which is not suitable for breeding frogs. In order to facilitate management, it is best to choose frogs with strong body, normal development and active actions from the same batch of frogs. After selection, the breeding frogs are put into the spawning pond to lay eggs according to the ratio of 1 male frog to 2-3 female frogs. Generally, 20 square meters spawning pond can put 1400-2000 breeding frogs. Aquatic plants or lotus seeds should be placed in the spawning pond, accounting for about one third of the water surface. The pool should be shaded by loofah or grapes. Try to avoid strong sounds and other noises around the pool. If a spawning pond is established in the center of the rice field, an spawning basket is set in the spawning pond, with an upper opening diameter of 30 cm, a lower opening diameter of 70 cm and a height of 40 cm. 20-30 groups of breeding frogs are placed in each spawning basket. Observe regularly. If you find any egg lumps, take them out and put them in an incubator. Then let the females who have laid eggs go and let the males hold them together. 2. Frogs mate and lay eggs. Frogs lay eggs from March to July every year, and the northern provinces lay eggs later. Southern provinces began to spawn in March, and April was the peak of spawning. However, the cuddling, mating and spawning time of breeding frogs are closely related to air temperature, water temperature in breeding ponds and water depth. When the water temperature is above 15℃, male and female frogs begin to refuse to mate. 18-28℃ is the optimum spawning temperature. When the spawning season approaches, male frogs keep chirping to attract female frogs. Male frogs usually go into estrus one week in advance. When the female frog is not in heat, she refuses to hug. In estrus, she often lingers in shallow water or clings to the male frog on the shore. Her stomach is swollen than usual, she is sexually impulsive, and her food intake suddenly decreases. Frogs can't be fertilized in vivo because they don't have mating devices. Instead, they complete the fertilization process by the male embracing the female. The male frog has an enlarged meat pad on the inside of his first finger, which is called a wedding pad. The wedding pad is rich in glands and horny thorns, and its secretions and horny thorns will strengthen the hug. When the female frog matures in estrus, the male frog jumps on the back of the female frog, and the forelimbs are held under the female frog, squeezing her abdomen with her calf, and swinging her hind feet at the same time, rubbing the female frog's reproductive hole, so that the female frog discharges eggs and the male frog ejaculates on the eggs. After laying eggs, the male frog leaves on his own. The female frog is in semi-shock state. After 1-2 minutes, she slowly leaves and rests in the shade. Frogs usually lay eggs for 1-2 days, sometimes as long as 3 days. Oviposition usually takes place at night, and the peak is before dawn. A female frog of more than 50 grams lays about 10000 eggs at a time. Frogs need a quiet environment when laying eggs. Slight vibration can temporarily stop spawning, while strong vibration or long-term interference will make it migrate to the spawning site. The process of spawning depends on the activities of the legs and feet of the male frog. When the legs and feet of the male frog stop moving, the female frog stops laying eggs. In case of strong cold wind attack, the water temperature suddenly drops below 15℃, and spawning will stop. At this time, you can try to raise the temperature to make it lay eggs normally. During the spawning period, if there are more male frogs than female frogs in the pond, there will be two male frogs of the same sex embracing each other or two female frogs embracing a female frog, and a third person embracing a male and a female frog, or embracing the female frog in the opposite direction, which will make the female frog unable to lay eggs normally or even die. Therefore, the frogs in the spawning pond must keep the ratio of one male and two females (or three females). Not every mature frog can lay eggs. For example, the environment is not adapted, the development is not good, the constitution is poor, the climate is not good, and so on. In order for frogs to lay eggs and hatch neatly, it is necessary to lay eggs artificially. Pituitary injection is usually used: open the top shell of frog head and take out the brain. There is a white object about half a grain size under the brain, which is the pituitary gland. Put the pituitary gland into a settling tube, grind it with a glass rod, add physiological saline to dissolve it, and inject the female frog into the leg muscles with a sterilized injection tube, then the female frog can lay eggs twice. 4. The eggs produced by artificially collected eggs and hatched frogs are small and soft, muddy yellow and round. The eggs are protected by a layer of colloid film, which absorbs each other, floats on the water or adheres to aquatic plants. If the eggs sink to the bottom of the pool, you must try to attach them to aquatic plants. The egg retrieval time is about 10 every morning. Frog eggs and attached aquatic plants are picked up by an egg fishing net and an egg holding net, put into a bucket, and then gently put into an incubator. When laying eggs, try to keep the original direction, that is, face up and face the bottom of the pool. The wrong direction has a great influence on the hatching rate. The same batch of eggs should be put in the same incubator, so that the hatched tadpoles are the same size and easy to manage. If the eggs at different stages are put in a pool, the hatched tadpoles will grow at different speeds, and the weak ones will gradually weaken and die. During the incubation period, the water temperature must be kept between 20-25℃. When changing water and plates, if the water temperature suddenly rises and falls more than 5℃ or the water temperature is lower than 4℃, higher than 28℃ or gives a strong alarm, the frog will die. Therefore, when observing the hatching of frog eggs, the action should be light, and the pool water should not be stirred at will, so as to avoid the tadpole larvae drifting off the egg membrane and affecting the survival rate. After two days of incubation, frog eggs can shake slightly, become tadpoles in 3-4 days, and hatch tadpoles in about 5 days. V. Feeding management of frogs 1. Feeding and management of tadpoles Newly hatched tadpoles like to gather together and attach themselves to egg membranes or aquatic plants. At this time, the water temperature should be kept at 23-25℃, and within 5-7 days, tadpoles have weak adaptability to the external environment and the highest mortality rate. Lack of oxygen in water, excessive water quality and sudden change of water temperature will lead to a large number of tadpoles' death or even all of them. If you pick up the film at this time, tadpoles are also prone to death, stunting, slow growth and weak constitution. It is best to raise tadpoles in the original incubation pond for 7- 10 days and then transfer them to the tadpole pond for breeding, so as to improve the sea-forming rate. Tadpoles are still young when they turn to the pool, and their swimming ability is poor. They must rely on suction cups to rest, and put more branches and aquatic plants in the pool. After giving birth to hind limbs, tadpoles like to perch under mud or grass roots. In the low pressure and sultry weather on the eve of the storm, tadpoles are very restless, swimming vertically up and down to the surface for air, or swimming with their bellies up and their mouths out of the water. In stagnant water, tadpoles have no appetite and don't swim much because of lack of oxygen in the water. Pay attention to the change of water quality. Keep the water temperature at 23-25℃. If the water is unclean or the pH value is too high, tadpoles are in danger of death. During the observation, if two-thirds of tadpoles in the whole pond are found floating on the water surface, refusing to go deep into the bottom, and unable to swim, it means that the temperature is too high or the plankton in the water is too dense, which affects the water quality, the water is unclean, or the oxygen in the water is insufficient. And replace the fresh water in time, clean up the residual bait in time to avoid the danger of death. Tadpoles should pay special attention to new feed, and supply it according to different growth periods of tadpoles. After 5 days, you can start eating phytoplankton. You can replenish some soybean milk, a small amount of egg yolk, Daphnia, spinach, papaya, tomatoes and zooplankton twice a day, but the amount of egg yolk should not be too much, so as not to affect the water quality. You can also feed some dung maggots in the toilet or maggots bred by sand head fish. Animal feed and plant feed should increase each other. Concentrate can be added. Corn and wheat bran 1: 2 are boiled into paste and fed together in plant feed, 3-4 times a day. After a month, the feed can be thicker, such as watermelon skin, rotten pumpkin, tomatoes and other feeds. In addition, we should start to feed some mixed feed, and the formula adopted is: rapeseed cake (powder) 60%, rice bran (or wheat bran) 30%, bean flour 5% and fish meal 5%, and the daily dosage is 50 grams per 100 grams. Animal feed consists of Daphnia, red worms, snails, dead fish and carrion. Animal feed should be chopped and put on the feed table, and powder feed can be distributed directly. The feed table is made of wooden boards and placed in the depth of 10 cm underwater. In addition, Chlorella can be cultivated, fertilized and fertilized, and plankton can be cultivated to feed naturally. Chlorella is rich in nutrition, containing about 40-50% of protein, which is equivalent to two portions of peanuts and five times of eggs. Known as "pork in water". It breeds quickly, and can breed 10- 100 times a day, so it is an ideal feed for raising tadpoles. Under the condition of 18-28℃, the feed supply was normal, and the frog hind limbs began to grow 20 days after hatching. After about 50 days, the forelimbs grow again. At this time, tadpoles stop eating and eat by sucking their tails. At the same time, the tail and gills degenerated and began to stick their heads out of the water and breathe with their lungs. After about 10 days, the frog's tail was absorbed and began to land. At this time, going back to the water is not diving, but swimming on the water. The whole tadpole period is 60 days.