GED Science TestLife ScienceEasy
A scientist is studying a population of bacteria that has developed resistance to a common antibiotic. This resistance allows them to survive and reproduce more effectively in the presence of the antibiotic. Which of the following biological processes best explains the increase in the proportion of resistant bacteria over generations?
- ANatural selection
- BArtificial selection
- CGenetic drift
- DGene flow
Show answer & explanationAnswer & explanation
Correct answer: A. Natural selection
Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring. In this case, antibiotic resistance provides a survival advantage, leading to an increase in resistant bacteria over generations.
Why the other options are wrong
- B. Artificial selection is selection imposed by humans, not by environmental pressures like antibiotics.
- C. Genetic drift refers to random changes in allele frequencies, not driven by selective pressure.
- D. Gene flow is the transfer of genetic material between populations, not the mechanism for increasing advantageous traits within a population under selective pressure.
Natural Selection
The process by which populations of living organisms adapt and change. Individuals in a population are naturally variable, and those variants best suited to their environment tend to survive and reproduce more successfully.
- Requires variation within a population.
- Involves differential survival and reproduction.
- Leads to adaptation over generations.
Memory trick: Evolution's Force: Natural selection, Mutation, Gene flow, Genetic drift.