why does the prey population change when they are eaten by predators?

The prey population decreases when they are eaten by predators because predation directly reduces the number of individuals in the prey population. This decline can lead to a shift in the ecosystem, as fewer prey can affect plant life and other species that rely on them for food. Additionally, the dynamics of predator-prey relationships can lead to fluctuations in both populations over time, often resulting in cycles of abundance and scarcity. Overall, the interaction between predators and prey is a key factor in maintaining ecological balance.