What is the growth process of a frog? A detailed explanation

Frogs are animals of the class Amphibia, order Anura. Adults have no tail, eggs are laid in water and fertilized externally, hatching into tadpoles that breathe with gills. After metamorphosis, adults mainly breathe with lungs and also through their skin. However, scientists have found that a species of frog living in the rainforests of Sulawesi Island, Indonesia, is able to give birth to tadpoles. Let us take a look at the growth process of a frog below!

Fertilized egg

The breeding time of frogs is around mid-to-late April each year. During reproduction, frogs have a very special phenomenon——amplexus, in which the male and female frogs clasp each other, the female frog releases eggs, and at the same time the male frog releases sperm. The sperm and eggs complete fertilization in the water, avoiding any time gap and greatly increasing the fertilization rate.

Tadpole

The tadpole is an early stage in the individual development of amphibians. The early small tadpole has a round or oval body, resembles a fish in appearance, and has a lateral line organ. Because no opening has yet appeared in the mouth, it cannot take in food. Later the eyes and nostrils appear one after another, and below the head there is a sucker that can be used to attach to aquatic plants. On both sides of the head there are external gills with a respiratory function. The tail is large and flat, containing segmented tail muscles, with membranous upper and lower tail fins above and below the myomeres, which help the tadpole swim in the water.

Young frog

Through metamorphosis and development, the tadpole grows four limbs, its tail is absorbed, and it comes ashore to live. Because both its physiology and environment change, its vitality is very weak and its ability to adapt to the environment is poor. For example, a dry environment, exposure to scorching sun, or being beaten by heavy rain can all cause it to die.

Adult frog

After a series of further growth, the young frog finally grows into an adult frog. Because its skin is bare, it cannot effectively prevent the evaporation of water from its body, so it cannot live without water or a moist environment throughout its life and is afraid of drought and cold. Therefore, most live in rainy regions of the tropics and temperate zones, and very few species are found in the frigid zone.