John tyndall and Ferdinand Cohn discovered that there were two types of bacteria exisitng in nature: those who are affected by heat leading eventually to their demise and those that are resistant or immune to a certain degree of heat. This finding is important in the devising of the sterilization process which it was recognized as a method of killing bacteria by applying heat to the medium. Later on, Cohn discovered the existence of endospores. Today, there are various types of bacteria, the thermobacteria, the cryobacteria- bacteria that are prone to cold temperatures and the bacteria that thrive on temperatures from 30-35 degrees normally.