Question

By a currently favored hypothesis, species richness of a community is greatest between physical disturbances of _____ intensity or frequency. a. low c. high b. intermediate d. variable

Short answer

b. intermediate

Step-by-step solution

Understanding Species Richness

Species richness refers to the number of different species present in an ecological community. It is an important measure of biodiversity.

Exploring the Intermediate Disturbance Hypothesis

The currently favored hypothesis related to species richness is the Intermediate Disturbance Hypothesis. This hypothesis suggests that species richness is maximized when disturbances are of intermediate frequency and intensity.

Evaluating the Options

Let's evaluate the provided options in light of the Intermediate Disturbance Hypothesis. Option b, 'intermediate,' matches this hypothesis, as it posits that intermediate levels of disturbance allow both competitive species and opportunistic species to coexist, thereby maximizing species richness.

Selecting the Correct Answer

Based on the Intermediate Disturbance Hypothesis, the option that completes the sentence appropriately is 'intermediate.' Therefore, the correct choice is option b.

Key concepts

Species Richness

Species richness is a fundamental concept in ecology that represents the total number of different species present within an ecological community. It's not just the quantity of organisms that matters, but the diversity of species. For example, a forest with 20 different species of trees has higher species richness than a forest with only 10 different tree species, even if the total number of trees is the same. Species richness is an important indicator of the health and stability of an ecosystem. A community with a high number of species tends to be more resilient to changes and disruptions, as it doesn't rely heavily on a single species for ecosystem functions. To better understand species richness, think about:

• Diversity: More variety often leads to healthier ecosystems.
• Equilibrium: Ecosystems strive for a state of balance, and species richness contributes to that balance.

Biodiversity

Biodiversity is the broader term that encompasses species richness but also includes two additional aspects: species evenness and genetic diversity. While species richness counts the number of species, species evenness refers to how evenly individuals are distributed among those species. Genetic diversity refers to the variation of genes within species. Together, these elements create a rich tapestry of life that supports ecosystem complexity and resilience. Consider the following about biodiversity:

• Interconnections: Biodiversity promotes interactions between species, such as pollination, predation, and symbiosis.
• Adaptability: More biodiversity means greater adaptability to external changes like climate shifts.

Biodiversity is crucial for ecosystem services, such as clean water, nutrient cycling, and resilience against disturbances. Protecting it is synonymous with safeguarding our own environmental stability.

Ecological Community

An ecological community is a network of interacting species inhabiting a common area. These species share the environment, engaging in various relationships like competition, predation, and cooperation. Ecological communities are structured by biotic (living organisms) and abiotic (non-living elements like soil and climate) factors. These communities are dynamic; they constantly change in response to succession, disturbances, and human influence. Features of ecological communities include:

• Complexity: Multiple layers of interactions build a balanced ecosystem.
• Succession: Over time, communities evolve through natural progression stages, from disturbance recovery to stability.

Understanding ecological communities helps scientists manage ecosystems, conserve habitats, and restore areas affected by human activity.