Question

Appearance of antibiotic resistant bacteria is an example of:

• A. Adaptive radiation
• B. Transduction
• C. Pre-existing variation in the population
• D. Divergent evolution

Answer 1

The correct option is C

Pre-existing variation in the population

The correct option is C.

Explanation for the correct option:

1. Antibiotics are antimicrobial drugs obtained from various organisms (such as moulds, fungus, and also some soil bacteria) to combat harmful microorganisms.
2. Antibiotics commonly block biochemical pathways important for the growth of bacteria.
3. The virus generally lacks cellular machinery & hence does not have biochemical pathways like a bacterial, plant, or even animal cells.
4. Antibiotics act on specific biochemical pathways to kill or even stop the growth of an organism.
5. Viruses use the cellular machinery of the host cell for replication and hence, antibiotics do not work on viral infections.
6. When a bacterial population is brought in contact with an antibiotic. Bacteria that are sensitive to it die.
7. Some bacteria having mutations become resistant to antibiotics and survive and multiply quickly.

Explanation for the incorrect options:

Option A:

1. Adaptive radiation is the evolutionary process by which many species originate from one species in an area and radiate to different species.
2. Because adaptive radiation is the development of many functional structures from a common ancestral form, i.e. divergent evolution, it is not the cause of the problem.

Option B:

1. Transduction is a mode of genetic transfer from one bacteria to another through a virus.
2. There is no direct contact between the bacterial cells.

Option D:

1. Divergent evolution refers to the process by which different organisms having common ancestors develop different traits to adapt to varying environmental conditions and needs.

Final answer: The appearance of antibiotic-resistant bacteria is an example of pre-existing variation in the population.