We all are familiar with our favorite beverage of inebriation: beer. Of course, we couldn’t get it without some help from our fungi friends.
Yeast is a fungus which as a part of its metabolic processes converts sugars into ethanol (what we refer to generally as alcohol). This is a biologically expensive process that doesn’t produce anything that the yeast can directly use, so why produce ethanol in the first place?
Biologists suggest that the production of ethanol is actually a defense mechanism for the yeast. As ethanol is an anti-biotic (it is one of the main ingredients in hand sanitizer and the like), the yeast uses it as a way to kill off competitors and defend itself. The yeast itself is not entirely immune from the effects of ethanol, it just has a much higher tolerance to it that enables this awesome evolutionary strategy to work.