Why are additional classification levels necessary?

Question

When I was in school I learned that all organisms can be classified using the seven levels kingdom, phylum, class, order, family, genus, species. In the course of teaching my own children now, and in looking up information about animals with them, I find that there are additional levels like superorder and infraorder. Is there a scientific reason why these levels were added? Are the seven levels i learned insufficient?

I learned then with a lovely mnemonic, would be a shame to have to dispense with King Phillip and what he allegedly came over for...

What if you want to describe a group of organisms in between some of these arbitrary levels? — Bryan Krause, Jul 04 '22 at 01:03
Relevant question on the usefulness of these designations: https://biology.stackexchange.com/a/55667/27148 — Bryan Krause, Jul 04 '22 at 02:27

score 3 · Answer 1 · answered Jul 04 '22 at 04:43

It’s been my experience that these additional levels pop up when the more typical rankings are huge. For example, the family Asteraceae has so many genera that to even begin to work on the phylogeny of such genera without repeatedly listing dozens of names requires prior subgrouping of the family into subfamilies and tribes.

Why are additional classification levels necessary?

1 Answers1