Chemistry PhD = Hubris ?

As penicillium mold spores drift about through the air, the fortunate ones land on a suitably moist food supply.

The spores almost need the moisture more than the food , as they can feed on almost any organic matter.

But when they get stressed, usually when the food supply runs low , they may respond by producing the antibiotics we rather loosely call by the single word 'penicillin' , to keep at bay bacterial competitors for that same food.

Note I said antibiotics in the plural, because, depending on the particular food source at hand, each penicillin produced might be in fact ever so slightly different.