[eli5] Why do insects have lots of legs while larger animals have 4 or 2? Also, why aren’t there any animals (that I know of) with 3 legs?

Question

[eli5] Why do insects have lots of legs while larger animals have 4 or 2? Also, why aren’t there any animals (that I know of) with 3 legs?

In: 381

Answer 1

More redundancy -> good

More total cells -> more room for errors

A simple insect leg adds few cells for a lot of redundancy, an additional human leg adds a lot of cells for a little redundancy.