Insects are a major group of arthropods and the most diverse group of animals on Earth, with over a million described species, more than half of all known living organisms, with estimates of undescribed species as high as 30 million, thus potentially representing over 90% of the differing life forms on the planet.

Arachnids are a class (Arachnida) of joint-legged invertebrate animals in the subphylum Chelicerata.