Explain how bacteria may become resistant to antibiotics

Bacterial resistance to antibiotics is an example of natural selection. In a population of bacteria there may be some individuals that are not affected by the antibiotic. This may be due to random changes or mutations that occur in the genes of individual bacterial cells. Some of these mutations protect the bacterial cell from the effects of the antibiotic. These individuals survive and reproduce with less competition from the normal bacterial strains that do not have the mutation for protection against the antibiotic, creating more bacteria that are resistant to the antibiotic.