Toad: one of the best known amphibians
Introduction (what they are / main groups)
Amphibians are living beings that during their life cycle go through two phases: one aquatic and one terrestrial. This species is classified into two main groups: tailed and tailless amphibians. Those without a tail (frogs and toads) are more developed than those that have (salamanders).
Amphibian Life Cycle
At the beginning of their life cycle, they live exclusively in the water and at this stage they have the form of fingerling (baby fish), performing only gill breathing.
After their metamorphosis, they no longer depend exclusively on the aquatic environment for survival and live in terrestrial habitat; however, this new environment should be humid to ensure the survival of this species.
Although they have lungs, their alveoli are insufficient to supply all the necessary gas exchange for their survival. For this reason, they absorb oxygen through the skin, and this process is much more efficient as they keep it moist, so they need to live in humid environments.
Its reproduction is external sexual, this process occurs when the male throws his gametes in the eggs released by the female. In general, this process will occur in freshwater, and once fertilized, the eggs remained in the aquatic environment until the tadpoles were born.
Because they are protected by water, amphibian eggs do not require adaptive embryonic attachments such as the amniotic sac. This is one of the characteristics that make them different from terrestrial vertebrates.
Most known species:
- Frogs, newts, salamanders, tree frogs and frogs.
The branch of zoology that studies amphibians and reptiles is known as Herpetology.
- The largest amphibian in the world is the Giant Salamander (Andrias davidianus). This animal can reach 1.8 meters in length. Salamanders of this species live mainly in the waters of mountain lakes in Japan and China.
Salamander: a little known amphibian species.