How does resistance to a pesticide occur?

How does resistance to a pesticide occur?

• A. The pesticide kills only resistant pests.
• B. The pesticide kills all pests regardless of susceptibility.
• C. The pesticide kills the susceptible individuals in a pest population, leaving only the resistant pests to reproduce.
• D. Pests mutate to become resistant immediately.

Answer: (C)

Resistance to a pesticide develops when there is genetic variation in how pests respond to the chemical. A pesticide tends to kill the susceptible individuals, while those with resistance survive and reproduce, passing the resistant trait to their offspring. Over generations, the frequency of resistance increases in the population, so the population as a whole becomes more resistant. This is natural selection at work under pesticide pressure. It isn’t an instantaneous change or caused by killing only resistant pests; resistance spreads because surviving resistant individuals pass their genes to the next generation, often starting from pre-existing variation and accumulating mutations over time.

Resistance to a pesticide develops when there is genetic variation in how pests respond to the chemical. A pesticide tends to kill the susceptible individuals, while those with resistance survive and reproduce, passing the resistant trait to their offspring. Over generations, the frequency of resistance increases in the population, so the population as a whole becomes more resistant. This is natural selection at work under pesticide pressure. It isn’t an instantaneous change or caused by killing only resistant pests; resistance spreads because surviving resistant individuals pass their genes to the next generation, often starting from pre-existing variation and accumulating mutations over time.