Why is genetic diversity important for populations facing environmental change?

• A. It increases the likelihood that some individuals possess traits suited to new conditions, aiding survival and reproduction.
• B. It reduces adaptation.
• C. It ensures all individuals are identical.
• D. It is irrelevant to survival under change.

Answer: (A)

Genetic diversity in a population provides a pool of different traits that may prove advantageous when the environment changes, increasing the chances that some individuals survive and reproduce. When conditions shift—like new temperatures, available food, or predators—variants that help individuals cope with the new situation become more favored by natural selection. Over time, these beneficial alleles become more common, helping the population persist despite the change. If there isn’t much genetic variation, the population may lack individuals with the right traits and could struggle to adapt.

For example, in a plant population facing drought, there may be some individuals with genes that improve water-use efficiency. Those plants survive, reproduce, and pass on those genes, while others perish. The other options don’t fit because reducing adaptation, ensuring everyone is identical, or saying diversity is irrelevant would all undermine the ability to cope with new environmental pressures.