Over the observed generations, there has been a significant decline in the population of gray frogs and a corresponding increase in the population of green frogs. In Generation 1, gray frogs made up more than 80% of the population, while green frogs constituted less than 20%. By Generation 2, the percentage of gray frogs decreased to 70%, and this downward trend continued into Generation 3, where they represented 60% of the population. In Generation 4, gray frogs accounted for less than 40%, while green frogs increased to more than 60% of the population.
The change in the population of gray frogs can be attributed to natural selection driven by the change in the environment. Initially, when vegetation was gray and dull, gray frogs had a camouflage advantage, which helped them avoid predators such as owls, snakes, and raccoons. However, with the increase in rainfall, the vegetation transitioned to a greener and more vibrant state. In this new environment, the green frogs had a camouflage advantage over the gray frogs, making them more difficult for predators to spot.
As a result, the green frogs experienced higher survival rates and reproductive success, leading to their population increase over the generations. In contrast, the gray frogs, being less camouflaged against the now green landscape, became more susceptible to predation, resulting in their decline. This illustrates the principles of natural selection, where environmental changes can favor certain traits that enhance survival and reproduction, ultimately leading to shifts in population dynamics over time.