- The moth population is shifting from predominantly light-colored moths to predominantly dark-colored moths over time due to natural selection. As the tree bark became darker from soot pollution, light-colored moths were more visible to predators and thus had lower survival rates, while dark-colored moths were better camouflaged and survived to reproduce more successfully.
- If there were no birds to eat the moths, natural selection based on camouflage would not occur. Both light and dark moths would have similar survival rates regardless of tree color, so the frequency of each color morph would likely remain stable or change only due to random factors (genetic drift), not selective pressure.
- If England maintains clean air quality as in 1995 for 25 or 75 years, we would expect the proportion of light-colored moths to increase again over time. With cleaner air, tree bark becomes lighter, making dark moths more visible to predators. Light-colored moths regain their camouflage advantage, leading to higher survival and reproduction rates, gradually restoring their dominance in the population.
Parent Tip: Review the logic above to help your child master the concept of evolution natural selection worksheet.
