Humans and insects are often said to be the dominant animals on earth. And yet there's only one species of humans and over seven hundred thousand of insects. How would you explain this phenomenon?

Answer 1

http://www.iflscience.com/plants-and-animals/why-are-there-so-many-species-of-bugs-but-so-few-species-of-human/

Answer 2

<<Insects are a class. is a family. It's on the same level as comparing the means of millenia with the means of decades, as was done in that reproachful climate graph not so long ago. The family happens to be monotypical, like the Cocos family. So, why aren't there more coconut species? Bad bad coconut.>> Insects have had much more time to form a diversity over ages, has not. Time is the key to genetic mutation diversity.