In a wild rodent population inhabiting a grassland region, individuals display variation in coat color ranging from light beige to dark brown due to multiple alleles. Following dark soot deposition across the habitat from nearby industrial activity, light-colored rodents become significantly more vulnerable to visual predators. According to modern evolutionary theory (Neo-Darwinism), which mechanism explains the resulting change in coat color distribution over successive generations?
- Differential survival and reproduction of individuals carrying pre-existing dark coat alleles, resulting in an increased frequency of dark alleles in the gene pool.Answer
- BIndividual rodents developing darker fur during their lifetime in response to environmental soot and directly passing this acquired somatic trait to their offspring.
- CThe misclassification of polygenic coat color variation as a non-heritable discontinuous trait that shifts independently of germline allele transmission.
- DLight-colored rodents undergoing protective mimicry by intentionally altering their anatomical structure to resemble unpalatable predatory species.
Answer
Natural selection acting on pre-existing genetic variation, leading to an increased frequency of advantageous alleles in the gene pool over generations.
Under modern evolutionary theory (Neo-Darwinism), natural selection acts upon pre-existing genetic variations in the population. Rodents carrying alleles for darker coats possess a selective advantage due to improved camouflage against soot-covered substrate, allowing them to survive, reproduce, and pass those beneficial alleles to the next generation, thereby increasing the dark allele frequency in the gene pool.
Step-by-Step Solution
Key Concept
Neo-Darwinian Natural Selection and Gene Pool Allele Frequencies