Just had a thought !! is it possible that all the bacteria in the world have a bacteriophage waiting to kill them up ? like, one bacteria, one bacteriophage ? does it have any evolutionary significance ? all kind of suggestions are welcomed !!
More like an evolutionary arms race - bacteriophages need to recognize specific proteins on the bacterial surface in order to infect and kill the bacteria. This puts selective pressure on the bacteria to mutate these surface feature to escape predation from the phages, until these, through mutations in their recognition modules, adapt to the alteration in the bacteria and again are able to infect.
In addition, bacteria have internal mechanisms to fight off infections, e.g. restriction enzymes to cut up foreign DNA and the CRISPR/CAS system representing a kind of adaptive defense against foreign genes.
There is no need for a one-to-one ratio between phages and bacteria, but being susceptible to many types of phages represents a selective disadvantage for bacteria, while recognizing a wide variety and very abundant types of bacteria represents a selective advantage for phages.
Basically, the relationship between bacteriophages and bacteria is a predator/prey relationship.
There is this saying (if one can call it like that), that for each species, there is a predator/pathogen (at least one). So yeah, even bacteria have their own pathogens. As Annemarie wrote, it won't be exactly one-on-one ratio, but there is likely some pathogen/predator for each bacteria.
Of course, besides viruses that infect bacteria, there are also more conventional predators, such as unicellular eukaryotes that "eat" bacteria by phagocytosis and multicellular organisms such as nematodes that feed on bacteria. These are less dependent on direct molecular interactions and therefore probably have a wider range of pray. In addition, there is the constant chemical warfare between microorganisms that is the source of many antibiotics.
great !! Annemarie Honegger Tomáš Hluska ,
Thank you for your response.