A lot more can be said about this but as a rough approximation, biological taxonomy is the science of determining the degree of kinship between organisms, where the most closely related species are placed in the same genus, closely related genera are placed in families, families joined in orders, orders in classes, and finally classes in kingdoms. Insecta are a class, consesting of about thirty orders. Orders are e.g. earwigs, termites, beetles, true bugs and butterflies. The 30 orders of insects are pretty easy to tell apart at a glance, at least for an experienced entomologist.