antibiotic resistance: Evidence for evolution

• Bacteria can evolve quickly because they reproduce at a fast rate.
• a random mutation might cause some bacteria to become resistant to certain antibiotics, such as penicillin.
• antibiotics usually kill bacteria, but in this case the mutation means the bacteria cannot be destroyed by the antibiotic. this evolution of antibiotic resistance in bacteria is an example of natural selection leading to evolution.
• 1. a random mutation occurs in the DNA of individual bacteria cells
• 2. the mutation protects the bacterial cell from the effects of the antibiotic- it becomes antibiotic resistant
• 3. bacteria without the mutation die when the antibiotic is present
• antibiotic resistant bacteria survive and can reproduce with less competition from non-resistant bacterial strains
• 5. the alleles for the antibiotic resistance are passed on to the offspring.
• 6. over time the whole population of bacteria become antibiotic resistant because the antibiotic resistant bacteria are best situated to the environment