1, Cyclostoma: the most primitive class of vertebrates, which has no maxilla and mandible, and is also called Anjawa. There are more than 70 species, mainly lamprey and blind eel. Living in the sea or fresh water, without appendages, parasitic or semi-parasitic life, with large fish and turtles as hosts.
2. Fish: Fish appeared about 450 million years ago, and there are about 32,000 kinds of fish in the world. It has a tail without limbs, and its tail is forked. It breathes through its gills and lives in water. It is an oviparous animal and its body temperature is not constant. Bony fish
3. Amphibians: Amphibians appeared about 350 million years ago. It has a tail and no limbs. Larvae breathe through gills and live in water. They live on land or in water, have no tail and limbs, and mainly breathe with their lungs. When they are in water, they can breathe with their skin. In oviparous animals, the body temperature is not constant.
4. Reptiles: Reptiles on the earth appeared about 300 million years ago. Reptiles generally crawl close to the ground, with lungs in their bodies and scales and nails on their surfaces. There are horny scales or nails on the skin surface, breathing with lungs, laying eggs, living on land, and having unstable body temperature. Beaktops (cuneiform lizards), turtles (turtles), scales (lizards) and crocodiles.
5. Birds: The earliest birds appeared about 65.438+0.5 billion years ago. The body is spindle-shaped, the forelimbs are specialized into wings, the body surface has feathers, the body temperature is constant, the chest muscles are developed, the bones are healed, and the brain is thin and hollow. A light-weight ovipositor. Beaks have no teeth, feathers on the body surface, and most of them can fly by breathing with their lungs.
Mammals: The earliest mammals appeared about 200 million years ago. At present, they are the most functional animals in the animal kingdom. Body hair, constant temperature, viviparous, breastfeeding, breathing with lungs. Among mammals, bats are the only animals that can fly. Mammals are the highest of all animals.
Extended data:
Vertebrates are closely related to human life. They provide human beings with food such as meat, eggs and milk, leather products such as leather clothes and shoes, and clothing products such as sweaters and down jackets. In addition, many vertebrates can prey on pests and pests in agriculture and forestry, which is beneficial to agriculture and forestry. According to statistics, a frog can kill 10,000 pests a year, while toads prey on more pests.
A woodpecker can eat nearly ten thousand pests that harm trees a year. The rodents destroyed by an owl in one summer is equivalent to an increase of 1000 kg of grain. The bat's ability to catch insects is even more wonderful. It can prey on mosquitoes, moths and other insects by using ultrasonic waves, so as to accurately determine their spatial positions. By studying the ultrasonic positioning mechanism of bats, people have developed an advanced instrument-radar.
References:
Baidu encyclopedia-vertebrates