Oscillation of Predator and Prey Populations

Question

Source: Oxford Designers & Illustrators Ltd/Pearson Education Ltd



On the graph (above), a healthy, stable predator-prey oscillation is shown. The blue line represents the population of a prey species, while the red line represents the population of a predator species. Assume that this specific predator eats this specific prey.

3. Use the graph above to determine if each statement (below) is accurate or inaccurate.

Scoring: Earn 1 point by getting 2 or 3 correct responses. Earn 2 points by getting 4 correct responses.

(2 points)
Accurate Inaccurate
There must always be a higher population of predators than prey in order for both populations to survive.

The two populations have no affect on each other. The fluctuations are just random.

A decrease in the prey population causes a subsequent decrease in the predator population because competition for food becomes more difficult.

An increase in the prey population causes a subsequent increase in the predator population because there is more food available for the predators.

Answer 1

To evaluate the accuracy of each statement regarding predator-prey dynamics based on the typical oscillation model, let's analyze each one:

1. "There must always be a higher population of predators than prey in order for both populations to survive."

   • Inaccurate: Typically, the prey population is higher than the predator population. Predators rely on prey for survival, but they do not need to outnumber them.

2. "The two populations have no effect on each other. The fluctuations are just random."

   • Inaccurate: Predator and prey populations are interdependent. The fluctuations in one population will affect the other, as seen in the oscillatory dynamics.

3. "A decrease in the prey population causes a subsequent decrease in the predator population because competition for food becomes more difficult."

   • Accurate: As prey numbers decrease, predators will have less food available, leading to a decline in their population.

4. "An increase in the prey population causes a subsequent increase in the predator population because there is more food available for the predators."

   • Accurate: When prey populations increase, predators have ample food supply, which supports an increase in their population.

So the evaluation results in:

• Statement 1: Inaccurate
• Statement 2: Inaccurate
• Statement 3: Accurate
• Statement 4: Accurate

Based on this analysis, you have 2 accurate statements (3 and 4), which means you score 2 points.