how many different species are there in the world??

Answer 1

Estimates of the present global macroscopic species diversity vary from 2 million to 100 million species, with a best estimate of somewhere near 10 million. Note the word macroscopic, this excludes microscopic oragnisms.

The U.S. has over 17,000 identified native plant and tree species, including 5,000 just in California. With habitats ranging from tropical to arctic, the flora of the U.S. is the most diverse of any country; yet, thousands of non-native exotic species sometimes adversely affect indigenous plant and animal communities. Over 400 species of mammal, 700 species of bird, 500 species of reptile and amphibian, and 90,000 species of insect have been documented.

Insects are the most diverse group of animals on the earth, with around 925,000 species described—more than all other animal groups combined. There's over a million arthropods, a group which includes insects.

About 350,000 species of plants have been estimated to exist. As of 2004, some 287,655 species had been identified, of which 258,650 are flowering.

I'm just adding them up.

Answer 2

Of what is known, the approximate answer is 1.5 million. 280, 000 plant species, 50,000 vertebrates, 750, 000 insects alone, 5,000 species of prokaryotes, maybe about 60,000 protists.

Answer 3

there are billions of species all over the world, more than anyone will know