@arnljot
That's Debian running on an Amiga rather than Ubuntu. Having said that, the version shown running (v3.1 a.k.a. Sarge) was released in 2005 and Ubuntu is based on Debian, started before 2005 and once had a PPC branch.
So to answer the original question, you could probably install an old version of Ubuntu on a powerful Amiga. Are you going to try it?
