Learn Turkish: Ekip beş kişiden oluşuyor. - The team consists of five people.

The verb oluşmak (to consist of) requires the ablative case (-den/-dan). While English says a team consists 'of' people, Turkish logic dictates that a whole is formed 'from' its parts.

Since there are five people, why isn't it plural (kişilerden)?

In Turkish, when a noun is preceded by a number, it always remains singular. Therefore, 'five people' is beş kişi, never beş kişiler. The case ending -den simply attaches directly to the singular noun, which is an earlier rule learners often forget when adding case endings!

The verb oluşuyor looks like it contains olmak (to be). Are they related?

Exactly! Oluşmak is derived from the root verb olmak (to be / to become). The suffix -uş changes the meaning to 'to come into existence' or 'to be formed.' When paired with the -den case, it means 'to consist of.'

Since we are currently learning olarak (as), could I use it here instead of -den?