How many animals are there on Earth? Please, thank you

To say exactly how many species of animals there are on the earth, I am afraid that even experts dare not guarantee it, because the understanding of animals is also accumulated with the continuous discovery of science and the continuous understanding of nature. Aristotle, the great scholar of ancient Greece, described 450 species of animals in the 3rd century BC; The first taxonomist of flora and fauna, Rinnai, described about 4,000 species of animals in the first half of the 18th century; In the first half of the 19th century, there were 48,000 known species of animals; By the end of the 19th century, there were 500,000 recorded animal species; At present, there are more than 1 million species of animals in the data, and according to taxonomists, this number still does not reach the actual number of species. In various scientific journals around the world, the discovery of hundreds of new species of insects is reported every year, which shows that our understanding of insects is far from enough.

In 1931, a total of 80,000 species of butterfly moths were known, and by 1942, 10,000 new species had been discovered. Some zoologists speculate that there may be 2 million species of insects in nature that are not well known. In vertebrates, fish are also understudied.

In 1938, off the coast of South Africa, a strange large fish was caught by chance, and the fishermen sent the fish to a local museum, and without detailed study, the skin of the fish was made into a specimen, and later, when the experts studied its specimen and skull, they found that the fish was extraordinary, it not only belonged to a new family independently, but also belonged to a new species, and the fish in this order had long been considered extinct millions of years ago. This fish is extremely rare, and in the six years from its discovery to 1954, only eight fish were caught. In addition, new species of mammals that we believe have been well studied are constantly being discovered, as evidenced by the discovery of the small rodent Cercythia rat.

Tens of millions of animals of millions of families.

According to zoologists, there are about 1.5 million known species of animals on Earth.

Animals can be divided into two categories: vertebrates and invertebrates, vertebrates have a vertebral column composed of many vertebrae on the back of the body, and the individual is generally larger; Invertebrates have no vertebral columns, and most of them are small, but they are diverse, accounting for more than 90 of the entire animal population. For example, insects such as flies, mosquitoes, grasshoppers, butterflies, etc., are invertebrates.

Vertebrates can be divided into five major groups: fish, amphibians, reptiles, birds and mammals.

Fish are the largest group of vertebrates, with a total of 25,000 to 30,000 species including marine fish and freshwater fish, such as carp and yellow croaker.

There are more than 2,000 species of amphibians, such as frogs.

There are more than 3,000 species of reptiles, such as snakes, turtles, crocodiles, etc.

There are 9,000 species of birds, such as pigeons, sparrows. There are more than 4,500 species of mammals, such as horses, cows, lions, tigers, etc.

There are still many species of animals in the world that have not yet been discovered.

About 1,250,000 (what the teacher said in class!) (*Hee-hee!!)

1.9 million species, because you're talking about animals.