A population of wild grass growing near an abandoned copper mine displays variation in copper tolerance. Over several generations, the proportion of copper-tolerant grass plants increased significantly in the contaminated soil surrounding the mine. According to Charles Darwin's theory of natural selection, which of the following best explains how this population evolved?
- Plants with pre-existing variation for copper tolerance survived and reproduced more successfully in the contaminated soil, passing the beneficial trait to their offspring.Answer
- BIndividual grass plants gradually developed copper tolerance during their lifetime in response to soil toxicity and passed this acquired trait to their seeds.
- CThe toxic copper in the soil directly induced specific beneficial mutations in the grass plants to enable their adaptation to the environment.
- DThe grass plants recognized the elevated copper concentration and deliberately modified their physiological processes to prevent extinction.
Answer
Plants with pre-existing variation for copper tolerance survived and reproduced more successfully in the contaminated soil, passing the beneficial trait to their offspring.
According to Darwin's theory of natural selection, populations contain pre-existing variations. When an environmental challenge (such as copper toxicity in the soil) arises, individuals possessing traits that confer resistance are more likely to survive and reproduce. Over successive generations, differential survival and reproduction increase the proportion of advantageous traits within the population.
Step-by-Step Solution
Key Concept
Darwin's Theory of Natural Selection