What are the stages of tadpoles becoming frogs?

1, the primary stage of tadpoles, early tadpoles, round or oval, fish-like, long and flat tail.

2, grow a small hind foot, the end is divided into five toes, the general shape has not changed, the eyes can be more agile, and the overall shape is slightly increased. Because there are no pores in the mouth, you can't eat.

After that, eyes and nostrils appeared one after another; There is a sucker under the head, which can be used to adsorb on aquatic plants. There are external gills on both sides of the head, which have respiratory function. There are segmented caudal muscles inside, and there are thin film-like upper and lower caudal fins above and below the sarcomere, which can help tadpoles swim in the water.

3. The hind legs are gradually elongated, with the basic shape of frog's hind legs, and the tail becomes more slender.

4, grow a forelimb, differentiate into five toes, the mouth is slightly prominent, and gradually distinguish the head from the body, the tail becomes thinner, but the overall shape increases.

Finally, all limbs are developed, eyes are prominent, mouth is enlarged, and tail can be brought or not, which can be called frog.

Extended data:

Frogs often inhabit rivers, ponds and rice fields, mainly in the grass near the water, and sometimes they can dive into the water. Mostly at night, mainly eating insects, but also eating some snails, snails, shrimps, small fish and so on. Most of the insects they eat are agricultural pests. It is estimated that a frog can prey on 70 insects a day and kill15,000 pests a year.

So frogs are good for agriculture and should be protected. When it gets cold in late autumn, frogs hibernate at the bottom of the water or in caves, and then return to the water to breed when the weather gets warmer the next spring. During the breeding season, many male frogs often gather in the same area and sing loudly and continuously. This is the so-called frog quarrel pit.

In fact, this is a courtship behavior of male frogs, which attracts the opposite sex by singing and forms a spouse. After mating, the female frog begins to ovulate in the water, with about 3000-6000 eggs at a time. At the same time, the male frog excretes sperm into the water. Sperm and egg cells combine in water to form fertilized eggs, which develop into tadpoles after 4-5 days of incubation.

Tadpoles must live in water, swim with their tails, breathe with their gills and eat plant foods such as diatoms and green algae. After two months of development, tadpoles turned into young frogs, their tails gradually disappeared, their body length was greatly shortened, they began to live on land, and their feeding habits began to change to animal food. It takes about three years from young frog to sexual maturity. ?

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