Question

In a certain forest, foxes prey on rabbits. A virus that infects only rabbits spreads through the forest, killing many rabbits. Which of the following is most likely to occur to the fox population? A. It will decrease, because the foxes will not have enough food. B. It will decrease, because the foxes will suffer from the virus. C. It will increase, because the foxes will no longer need to compete with the rabbits for food. D. It will increase, because the foxes will evolve to become more resistant to disease.

Short answer

The most likely outcome is A. The fox population will decrease because the foxes will not have enough food due to the decline in the rabbit population caused by the virus.

Step-by-step solution

1. Identify the relationship between foxes and rabbits

Foxes prey on rabbits, so the fox population depends on the rabbit population for food. If the rabbit population decreases, it directly affects the fox population.

2. Analyze the impact of the virus on the rabbit population

The virus infects only rabbits and leads to the death of many rabbits. This means there will be a decline in the rabbit population, affecting the food source for the foxes.

3. Evaluate each option

A. It will decrease, because the foxes will not have enough food. With the decline in the rabbit population, it's logical to assume that the foxes will have less food available, which could lead to a decrease in the fox population. B. It will decrease, because the foxes will suffer from the virus. Since the exercise explicitly states that the virus infects only rabbits, foxes are not affected directly by the virus. C. It will increase, because the foxes will no longer need to compete with the rabbits for food. This option doesn't make sense, as foxes prey on rabbits, and a decline in the rabbit population would lead to a decrease in available food for foxes, not an increase. D. It will increase, because the foxes will evolve to become more resistant to disease. This option is also not likely, as the exercise doesn't mention any direct impact of the virus on the fox population or their need to evolve in response to the virus.

4. Choose the most likely outcome

Based on the analysis of each option, the most likely outcome is: A. The fox population will decrease because the foxes will not have enough food due to the decline in the rabbit population caused by the virus.

Key concepts

Predator-Prey Relationship

In an ecosystem, the predator-prey relationship is a fundamental interaction where one organism, the predator, hunts and eats another organism, the prey. For example, in a forest, foxes hunt and eat rabbits. This relationship creates a balance in the ecosystem, helping control the population sizes of both predators and prey.
The predator-prey relationship is like a dance. When the rabbit population is high, foxes have plenty of food, and their population might grow. If there are too many foxes eating the rabbits, rabbit numbers might drop, leading to a food shortage for the foxes. This can result in a decline in the fox population.

• This relationship often follows a cyclical pattern, where the predator and prey populations rise and fall in response to each other.
• Such dynamics help maintain a natural balance, preventing populations from becoming too large or too small.

Understanding this relationship helps ecologists predict changes in population sizes and manage wildlife resources efficiently.

Impact of Disease on Wildlife Populations

Diseases can significantly impact wildlife populations, sometimes even altering predator-prey dynamics. When a disease affects one species, it might cause a ripple effect across the ecosystem. For instance, if a virus spreads among rabbits, it can reduce their numbers significantly.
The decline in the rabbit population due to disease decreases the food availability for the foxes. This is because rabbits are a crucial part of the foxes' diet. With fewer rabbits to hunt, foxes might struggle to find enough food, leading to a decrease in their population as well.

• This situation demonstrates how disease can indirectly impact other species through the food chain.
• It's also a clear example of how interconnected species are within an ecosystem. A change in one species can often lead to changes in others.

Managing wildlife disease is therefore crucial in preserving biodiversity and maintaining healthy ecosystems.

Food Chain Dynamics

Food chain dynamics describe the flow of energy from one organism to another within an ecosystem. Each species occupies a specific position in the food chain, referred to as a trophic level. In a simple food chain, grass may be eaten by rabbits, which are in turn preyed upon by foxes.
Food chains illustrate the dependency among organisms for survival. Each link in the chain is crucial; if one link is weakened or removed, it can create a domino effect throughout the ecosystem.

• In our example, the virus impacting rabbits upsets the established food chain, reducing food available for the foxes.
• This disruption highlights the importance of each species in maintaining the balance of ecosystems.

Understanding food chain dynamics helps us appreciate the complexity and fragility of ecosystems, and emphasizes the importance of conserving each species to maintain ecological balance.

Population Ecology

Population ecology is the study of how populations of organisms change over time and space. It looks at how births, deaths, immigration, and emigration affect populations.
Within a population, factors such as availability of resources, predation rates, disease prevalence, and competition for resources drive changes. In our forest scenario, a decrease in rabbit population due to a virus affects foxes, as they depend on rabbits for food.

• Population ecology helps us understand how the decline of the rabbit population will likely cause a decline in the fox population as well.
• Such studies also focus on how population densities and distributions are impacted by environmental factors.

Insights from population ecology can aid in wildlife management and conservation efforts, ensuring that populations remain sustainable and ecosystems thrive.