species on earth
Since the emergence of life on earth, it has experienced a long evolutionary process of 3 billion to 4 billion years. There are 20 million to 50 million species of living things, of which there are more than 1.5 million species of animals. But this is only a tiny fraction of the species that have ever lived on Earth. Even we know very little about these creatures. Insects are the most species of animals in the world. At present, there are more than 1 million species named, and 69,000 species are known in the world. There are about 150,000 species of insects in our country. 34,000 species. We know more about the higher groups in the animal kingdom. For example, it is estimated that there are 5,000 species of mammals, 4,181 species are known in the world, and 499 species are known in my country. It is estimated that there are 11,000 species of birds, 8,974 species are known in the world, and 1,186 species are known in my country. There are 6,300 known reptile species in the world, and 376 known species in my country. There are 4010 known species of amphibians in the world and 376 known species in my country. It is estimated that there are 28,000 species of fish, 21,400 species are known in the world, and 2,804 species are known in my country. Among so many kinds of animals, many species are unique to my country, including 73 species of mammals, 99 species of birds, 26 species of reptiles, 30 species of amphibians, and 440 species of fish. Due to the deterioration of the environment, the number of individuals of some animal species has decreased, making these animals endangered species. At present, there are 94 species of mammals, 183 species of birds, and 17 species of reptiles in China. The South China tiger is an endangered mammal. , As of the beginning of 2009, there are 81 South China tigers in the world. There are 7 species of amphibians and 97 species of fish.
fish
We all know the closeness between animals and our lives. Therefore, in order to protect animals, we must first protect the living environment of animals.
animal classification
There are many kinds of creatures distributed in nature. There are more than 2 million species discovered so far, of which there are more than 1.5 million species of animals, but scientists estimate that there are as many as 20 million to 50 million species of creatures living in nature. In order to study and utilize this colorful biological world, people use different hierarchical features to classify the creatures according to the degree of similarity and dissimilarity between them and the distance of their kinship. The grades from large to small are kingdom, phylum, class, order, family, genus, and species.
South China Tiger
Any known animal can be assigned to these taxonomic levels. For example, tiger belongs to the animal kingdom, Chordate, Mammalia, Carnivora, Feline, Panthera, and the species is called tiger; know that it belongs to the animal kingdom, Arthropoda, Insecta, Homoptera, Cicidae, Cicada, species called the grasshopper. Every animal has a scientific name, written in Latin, which consists of a genus and a species. This is the binomial method created by Linnaeus.
cell
Scientists have divided the animal kingdom into more than 30 phyla. Important animal phyla are protozoa: the simplest and smallest animals, whose bodies consist of a single cell, some of which can cause human diseases, such as malaria, which can cause human malaria. protozoa, the amoeba that causes dysentery in humans, the trichomoniasis that causes trichomoniasis, etc. Some of them are used by humans to monitor water quality as markers of water pollution. In water bodies with different pollutants or levels of pollution, the types and numbers of protozoa will vary.
Coelenterates
coral
We rarely see live animals of this type, but you must know that corals and seas. According to scientists’ estimates, there are as many as 20 million to 50 million species of creatures living in nature. But there are more than 2 million species discovered so far, of which there are more than 1.5 million species of animals. From a certain point of view, animals can also be divided into flying in the sky, swimming in water, living on land and amphibious.
crystal clear coelenterate
Stings, they are all coelenterates. Platyhelminthes: The body is flat and the body wall consists of a three-layer structure. Many flat animals are parasitic species, they are parasitic in humans or animals, such as pork tapeworms, schistosomiasis and so on. Linear Animals: Cylindrical bodies, many of which are parasites, such as roundworms, pinworms, and filarial worms, which can cause parasitic diseases in humans. Annelids: The body consists of many links, such as earthworms, leeches, etc. Molluscs: Soft bodies, often protected by shells, such as mussels and snails. Arthropoda: The body is divided into head, chest, abdomen, and appendages. Common shrimp, crabs, spiders, centipedes, locusts, etc. Echinoderm: Common are starfish, sea cucumber and so on. Chordate: The highest group of animals in the animal kingdom includes fish, frogs, geckos, birds, beasts, etc.