The graphs below depict hypothesized population dynamics (population size, N, vs. time) for a predator-prey system. Based on what you’ve learned in this tutorial by investigating moose and wolf population cycles, which graph best represents a predator-prey system, and which curve (blue or red) describes dynamics for the predator species? Time Time The graph on the left is the best representation, the predator’s curve is blue. The graph on the left is the best representation, and the predator’s curve is red. The graph on the right is the best representation, and the predator’s curve is blue. The graph on the right is the best representation, and the predator’s curve is red.
The Correct Answer and Explanation is :
The graph on the left is the best representation of a predator-prey system, with the red curve depicting the predator’s dynamics.
In predator-prey relationships, such as the moose and wolf populations you’ve studied, both species exhibit cyclical fluctuations over time. Typically, an increase in prey (e.g., moose) leads to a subsequent rise in predator numbers (e.g., wolves) due to increased food availability. As the predator population grows, it intensifies predation pressure on the prey, causing the prey population to decline. This reduction in prey results in food scarcity for predators, leading to a decline in their numbers. With fewer predators, the prey population can recover, and the cycle repeats.
Analyzing the left graph, we observe two curves exhibiting these cyclical patterns. The red curve lags behind the blue curve, indicating that changes in the red population follow those in the blue population. This lag is characteristic of predator-prey dynamics, where predator population peaks occur shortly after prey population peaks. Therefore, the blue curve represents the prey population, and the red curve represents the predator population.
In contrast, the right graph may not accurately depict predator-prey dynamics, as it might show synchronous fluctuations or lack the characteristic lag between predator and prey populations. Such patterns are inconsistent with the observed dynamics in systems like the moose and wolf populations, where predator numbers typically trail behind prey numbers due to the dependence of predators on prey for sustenance.
Understanding these cyclical interactions is crucial for ecological management and conservation efforts. Recognizing the natural oscillations in predator and prey populations helps in making informed decisions to maintain ecosystem balance and biodiversity.
In summary, the left graph accurately represents a predator-prey system, with the red curve illustrating the predator’s population dynamics, aligning with the typical cyclical patterns observed in such ecological interactions.