|MadSci Network: Microbiology|
Microorganisms (e. g., fungus, bacteria) have developed antibiotics to compete for food sources. Antibiotic production appears to be important to the survival of microorganisms through elimination of microbial competition for food sources, which are usually very limited in soil. Different types of antibiotics are made because these antibiotics have derived from accumulation of mutations in their genetic material and have evolved upon the microorganism they had to compete with. This evolution has led to different kinds of antibiotics with different anti-microbial targets and different specificities varying species to species and even from one strain to another. Antibiotic production is very common among soil-dwelling bacteria and fungi, and many of our most widely used medical antibiotics (e.g., streptomycin) are made by soil microorganisms. If they can make something that removes or drastically "slows-down" the competition for the available nutrients, then they'll have an advantage.
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