How long does it take for a new species to arise? have we ever witnessed a new species arising - like in any laboratories or otherwise - possibly with creatures with short life spans? does it happen all the time, or is it incredibly rare?

Arising of a new species is not a rare thing. Organisms are always in a competition to survive long. Speciation, as what they call it, is happening from time to time because organisms evolve in order to adapt to the environment where they are in. However, this process is a slow one thus it is almost impossible to see a new species arising.

The answer is cometm