Final answer:
Bacterial populations develop antibiotic resistance through the pre-existence of resistance genes, the presence of antibiotics selecting for resistant individuals, and the transfer of resistant alleles to subsequent generations. Antibiotics do not cause mutations but select for bacteria with natural resistance, emphasizing the need for responsible antibiotic use to manage resistance.
Step-by-step explanation:
For a population of bacteria to develop resistance to antibiotics, several factors contribute. Firstly, the existence of resistance genes in the population is crucial. These genes may exist at a low frequency but are essential for resistance to manifest. Secondly, the presence of antibiotics in the bacteria's environment acts as a selective pressure. This presence causes susceptible bacteria to die while those with resistance genes survive and reproduce. Lastly, the transfer of alleles from one generation to the next allows the resistance traits to be passed on, further contributing to the development of resistant populations.
It's important to note that resistance arises not because the antibiotic creates mutations for resistance but because the resistant genes are naturally selected for when the antibiotic kills bacteria without them. Incorrect use of antibiotics, such as not completing a full course, also contributes to the natural selection of resistant forms. This underlines the importance of responsible antibiotic use to prevent the spread of resistance.