Reptiles evolved from ancient amphibians at the end of Carboniferous. The heart has two atria and one ventricle, and the ventricles have an incomplete diaphragm, and their body temperature is not constant. They are truly adapted to terrestrial life, and thus they produce constant-temperature birds and mammals. Reptiles not only further adapt to land life in adult structure, but also get rid of the shackles of water in their reproduction, and are called amniotic animals with birds and mammals.
2. Mammals
A class of Vertebrates, commonly known as mammals. Most mammals are vertebrates with fur all over the body, fast movement, constant temperature viviparous and diaphragm in the body. They are animal groups with body structure in vertebrates, so they are named because they can breastfeed their young through mammary glands. Mammals can be divided into protothera, euthera and afterthera.
Mammals are distributed all over the world, living on land, underground, aquatic and flying in the air. There are two types of nutrition: herbivore and meat.
3. Amphibians
Amphibia, an amphibian, is a primitive, newly landed, five-toed, temperature-changing quadruped with bare skin, numerous secretory glands and mixed blood circulation. Its individual development cycle has a metamorphosis process, that is, the larvae living in water are breathed by gills (new organs), and metamorphosis is completed in a short time, becoming adults living on land with lung breathing energy.
4. Fish
Fish is the oldest vertebrate. Some hybrid offspring with different chromosome numbers still have fertility. They inhabit all aquatic environments on earth, from fresh lakes and rivers to salty seas and oceans.
5. Birds
Birds are a class of Vertebrates. The body is feathered, constant temperature, oviparous, and amniotic membrane outside the embryo. The forelimbs are winged and sometimes degenerate. Multi-camp flying life. The heart is 2 atria and 2 ventricles. Only the right arterial arch is preserved, and the left arterial arch is degenerated. Bone is porous and filled with gas. In addition to the lungs, the respiratory organs have airbags to assist breathing. Birds in China are divided into six categories: swimming birds, wading birds, climbing birds, land birds, raptors and songbirds.
Baidu encyclopedia-reptile
Baidu Encyclopedia-Mammalia
Baidu encyclopedia-amphibians
Baidu encyclopedia-fish
Baidu Encyclopedia-Bird Class