Antibiоtic resistаnce cаn evоlve rаpidly in bacterial pоpulations. Suppose that a type of bacterial infection is normally treated with antibiotic A. A person who has an infection with this type of bacteria takes antibiotic A, but it has no effect. It is determined that the bacteria causing their infection have a new allele that makes them resistant to the antibiotic because it cannot bind to the normal target molecule in the bacteria. How did the bacteria become resistant to the antibiotic? Side note: Fortunately for the person with the infection, it turns out there is another antibiotic that can be used to treat the infection, so the person recovers and is fine.