Biology without evolution is birdwatching. It's the collection of observations with no possibility of gaining fundamental understanding.
Don't look now, but you just admitted evolution is not observation.
On this we agree. It's speculation (and not even very good speculation).
On the contrary, the theory of evolution is irrelevant to serious scientific study. Variations within species do NOT prove this nutty theory. The theory of evolution is dependent on the belief that entirely new species are created by natural selectivity over time. That just can't happen, scientifically. Hence, the laughably expansive leap of faith as so-called scientists put their eggs in the evolution basket.
Not really. Only at highest levels of the ivory tower is this potentially the case.
In this issue it is 100% irrelevant.
Even, though, accepting evolution must accompany biology, a belief in it is irrelevant. Understanding and mastery of concept does not need to be linked to belief.