Ddt is a pesticide that was banned because of its negative impact on the environment. ddt weakened eggshells and caused the decline of many bird species, including bald eagles. which statement best summarizes the impact of ddt on bald eagles at a genetic level? ddt changed the genotype of the individual without affecting phenotypes, thereby decreasing adaptation. the ability to survive decreased because evolution cannot occur with low population numbers and low genetic diversity. ddt caused changes in dna that decreased the survival of offspring, thereby decreasing the overall numbers of the population. new alleles decreased genetic diversity within the population.