How is a frog bilineal? Is the frog an amphibian, what are its close relatives?

It can live on land and in water.

He can live both in the water and on land.

The frog is an amphibian, and his close relative is the toad.

Frogs belong to the amphibians of the phylum Chordates, amphibians, tailless, frogs, adults without tails, eggs laid in water, fertilization in vitro, hatching into tadpoles, respiration with gills, after mutation, adults mainly use lungs to breathe, and also use ** breathing. The upper jaw has teeth, usually vomer teeth. shoulder girdle fixed thoracic type, vertebral body uneven type, recommended vertebral transverse process columnar; There is no intermediated cartilage between the two bone nodes at the end of the toes.

The tympanic membrane is distinctly hidden under the skin,** smooth or with wart grains. The tongue is generally oblong, and the posterior end is mostly notched.

The frog body can be divided into 3 parts: head, trunk, and limbs. Frogs have four toes on their front feet and five toes on their hind feet, as well as webbed. On either side of the frog's head are two small bags that bulge slightly.

That's its eardrum, through which the frog can hear sounds. The frog's back is green, smooth, soft, and patterned, and its belly is white. You can hide it in the grass, make it easier to catch pests, and you can also protect yourself.

It's also helps it breathe. Its air sacs are only found by male frogs. Frogs prey on their tongues, which have mucus on their tongues.

Frogs belong to the amphibians of the phylum Chordates, Amphibians, Tailless, and Frogidae.

The adult body has no tail, the egg is laid in water, fertilized in vitro, hatched into a tadpole, respires with gills, and after mutation, the adult mainly uses the lungs to breathe, and also uses ** breathing. The vast majority of frogs reproduce through in vitro fertilization, and the fertilized eggs hatch into tadpoles outside the mother's body. Globally, only 10 to 12 species of frogs have evolved to fertilize in vivo, and some of them will release fertilized eggs from their bodies to hatch into tadpoles.

But frogs are zoological to refer specifically to the black spotted lateral fold frog.

The answer is that monkey is an umbrella term. There are many animals in the primate family that we call monkeys. Primates are one order of the class Mammalia.

The highest taxa of the animal kingdom, with a well-developed brain; orbits facing anteriorly, orbital spacing narrow; The toes (fingers) of the hands and feet are separated, and the thumbs are flexible, and most of them can be held opposite to the other toes (fingers). Including the protomonkey suborder and the simian suborder.

1. The primary stage of tadpoles, early small tadpoles, with a round or oval body, resembling a fish, and a long and flat tail.

2. Grow a small hind foot, the end of the differentiation of 5 toes, the general shape has not changed, the eyes can be more flexible, and the overall shape is slightly increased. Since there is no orifice in the mouth, food cannot be ingested.

Later, the eyes and nostrils appear one after the other; There are suction cups under the head, which can be used to attach to aquatic plants. The sides of the head have external gills and have respiratory functions. There are segmented tail muscles, and the upper and lower parts of the sarcomere have membranous upper and lower tail fins that help tadpoles swim in water.

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

4. One forelimb grows out, differentiating into 5 toes, the mouth is slightly protruding, and the head and body can be distinguished gradually, and the tail is thinner, but the overall shape is increased.

5. Finally, all the limbs are developed, the eyes are prominent, the mouth is enlarged, and the tail can be brought or not, then it can be called a frog.

The fossil record

Although the body of tadpoles is soft and difficult to preserve, there are still fossils of tadpoles from the Upper Miocene, up to 10 cm (in) in length, which have been preserved in the form of biofilms, with hard jaws and bones.

Tadpole fossils found in Livros, Spain, also contain brain shells in the form of calcium carbonate, nerve cords of calcium phosphate, and rock debris in the intestines.