GED Science TestLife ScienceEasy
A scientist is studying a population of bacteria that has developed resistance to a common antibiotic. She observes that the resistant bacteria are able to break down the antibiotic compound, rendering it harmless. This adaptation allows the resistant bacteria to thrive while non-resistant bacteria are eliminated. This is an example of which of the following?
- AGene flow
- BGenetic drift
- CMutation
- DNatural selection
Show answer & explanationAnswer & explanation
Correct answer: D. Natural selection
Natural selection occurs when individuals with advantageous traits (like antibiotic resistance) are more likely to survive and reproduce in a specific environment, passing those traits to their offspring.
Why the other options are wrong
- A. Gene flow is the movement of genes between populations, which isn't the primary mechanism described for the resistance development.
- B. Genetic drift is random changes in allele frequencies, typically in small populations, not directed by environmental pressure.
- C. Mutation is the source of new genetic variation, but natural selection is the process that acts on these mutations to increase the frequency of beneficial ones.
Natural Selection
The process whereby organisms better adapted to their environment tend to survive and produce more offspring.
- Acts on existing genetic variation.
- Leads to adaptation over generations.
- A driving force of evolution.
Memory trick: Natural selection 'selects' the fittest for survival.