The appearance and spread of MRSA is an example of __________.
MRSA has spread from hospital to community environments.
Question 1 of 2
Check Your Understanding
Incorrect. Antibiotic resistance is a trait exhibited by some bacteria. Resistance traits are heritable, or passed from each generation to the next. Therefore, the appearance and spread of bacterial strains like MRSA that are resistant to antibiotics indicates an increase in the frequency of a specific heritable trait over time. Try again.
The 2000 presidential election was only one example of what could happen in an unusual situation involving the Electoral College. This activity uses hypothetical situations to illustrate how the Electoral College can impact election outcomes.
Read each situation and determine election results in these “What If” situations.The Next button appears if you answer the question correctly.
Select the i button before beginning the activity.
Correct. Any change in the frequency of one or more heritable traits, including antibiotic resistance, that occurs in a population of individuals is an example of evolution.
Question 2 of 2
Correct. While poor hygiene and improper hand washing contribute to the spread of all bacteria, an antibiotic is designed to kill infecting bacteria. Widespread use of antibiotics, particularly when patients discontinue treatment early before all bacteria are killed, selects for the growth of bacteria already resistant to antibiotics. The rise in prevalence of bacterial strains like MRSA is a direct result of repeated antibiotic selection for survival of MRSA over other bacterial strains.
if antibiotic treatment ends before all bacteria are killed, the bacteria have time to mutate their DNA to produce chemicals enabling antibiotic resistance in preparation for future treatment
The failure to complete a course of antibiotics promotes bacterial resistance more rapidly because __________.
Incorrect. This behavior may promote the spread of bacteria, but does not explain an increase in the presence of MRSA bacteria over other bacterial strains. Try again.
bacteria carrying a gene that enables even minor resistance are more likely to survive and reproduce, spreading resistant traits throughout the population
antibiotics must build up inside the body to reach a concentration high enough to kill bacteria, making sensitive bacteria appear resistant because of low antibiotic concentrations