Problem 5 - Campbell Biology

Question

Predators that are keystone species can maintain species diversity in a community if they (A) competitively exclude other predators. (B) prey on the community's dominant competitors. (C) reduce the number of disruptions in the community. (D) prey on the least abundant species in the community.

Step-by-Step Solution

Answer

The correct answer is (B).

Step 1 - Understanding Keystone Species

Keystone species play a crucial role in maintaining the structure of an ecological community, affecting many other organisms in the ecosystem and helping to maintain biodiversity.

Step 2 - Analyzing the Effect of Predation

Keystone predators help to keep populations of other species in check. This means they can prevent any one species from becoming overly dominant, which can suppress other species and reduce overall diversity.

Step 3 - Evaluating the Options

Consider each option:(A) Competitively excluding other predators does not necessarily maintain diversity.(B) Preying on dominant competitors can prevent these species from monopolizing resources, thereby maintaining diversity.(C) Reducing disruptions might be beneficial, but it does not directly address species competition.(D) Preying on the least abundant species would further reduce their numbers and likely lead to extinctions, decreasing diversity.

Step 4 - Choosing the Correct Answer

Based on the understanding that keystone predators maintain species diversity by controlling dominant competitors, the correct answer is (B).

Key Concepts

Species Diversity

Species diversity refers to the variety of different species that exist within an ecological community. It is a key indicator of ecosystem health and stability. High species diversity means the ecosystem can withstand various environmental changes and disruptions better than ecosystems with low diversity.

In an ecosystem, different species interact with each other in various ways, such as through competition, predation, and symbiosis. Each interaction plays a role in shaping the ecosystem. The presence or absence of certain species can significantly affect the structure and function of the ecosystem.

For example, keystone species are often critical in maintaining species diversity. By preying on dominant species, they help balance the ecosystem and allow multiple species to coexist. This balancing act ensures no single species can dominate the ecosystem, thus maintaining high biodiversity levels.

Ecological Community

An ecological community is a group of different species living together and interacting within the same environment. These interactions form a complex web of relationships that define the community's structure and dynamics.

The concept of an ecological community encompasses several types of relationships, such as:

• Competition: When different species vie for the same resources, such as food or habitat space.
• Mutualism: When species interact in a way that benefits both parties, like bees and flowering plants.
• Predation: When one species (the predator) feeds on another species (the prey), which helps control the prey population.

Keystone species, such as certain predators, play an instrumental role in these communities by maintaining balance and promoting biodiversity. By regulating the population of dominant competitors, they prevent these species from overwhelming the community and monopolizing resources.

Predation Effect

The predation effect refers to the influence that predators have on the structure and composition of an ecological community. Predators regulate the population size of their prey, which can have wide-reaching impacts on the ecosystem.

When a keystone predator preys on dominant competitors within an ecological community, it prevents these competitors from monopolizing resources. This predation helps maintain a more diverse array of species by keeping dominant species populations in check.

Here’s why this balance is important:

• If one species becomes too dominant, it can outcompete other species for resources, causing those species' populations to decline.
• This decline can lead to a reduction in species diversity, which makes the ecosystem more vulnerable to disturbances.
• Therefore, by preying on dominant species, keystone predators contribute to a more resilient and stable ecological community.

The predation effect essentially ensures that no single species can dominate the ecosystem, allowing a wider variety of species to thrive and coexist.