Problem 1 - Campbell Biology

Question

One characteristic that distinguishes a population in an extinction vortex from most other populations is that (A) its members are rare, top-level predators. (B) its effective population size is lower than its total population size. (C) its genetic diversity is very low. (D) it is not well adapted to edge conditions.

Step-by-Step Solution

Answer

The correct option is (C): its genetic diversity is very low.

Step 1: Understanding the Question

Identify the key characteristic of a population in an extinction vortex. This process involves recognizing the most distinguishable trait associated with such populations.

Step 2: Analyzing Each Option

Evaluate each given option and determine how closely it relates to populations in an extinction vortex.

Step 3: Assess Option (A)

Consider the statement: 'its members are rare, top-level predators.' While top-level predators can be rare and vulnerable, this does not necessarily equate them with an extinction vortex.

Step 4: Assess Option (B)

Analyze the statement: 'its effective population size is lower than its total population size.' This is common in many populations, not just those in an extinction vortex.

Step 5: Assess Option (C)

Examine the statement: 'its genetic diversity is very low.' Populations in an extinction vortex typically suffer from low genetic diversity, which can accelerate their decline.

Step 6: Assess Option (D)

Review the statement: 'it is not well adapted to edge conditions.' While it can be a contributing factor, it does not singularly distinguish populations in an extinction vortex.

Step 7: Conclusion

By process of elimination and based on our analyses, the most distinguishing characteristic of a population in an extinction vortex is that its genetic diversity is very low.

Key Concepts

genetic diversity

Genetic diversity refers to the total number of genetic characteristics in the genetic makeup of a species. It is important because it enables populations to adapt to changes in the environment. Populations in an extinction vortex often have very low genetic diversity. This makes them more vulnerable to diseases and less able to adapt to environmental changes. For example, if all individuals in a population are very similar genetically, a single disease could wipe out the entire population. High genetic diversity ensures that some individuals have variations that might help them survive under different conditions.

effective population size

Effective population size is a measure of the number of individuals in a population who contribute offspring to the next generation. It is usually lower than the actual number of individuals in the population. This difference is due to factors like unequal sex ratios, variation in number of offspring produced by different individuals, and overlapping generations. Populations in an extinction vortex often experience a significant drop in effective population size. This reduces their ability to maintain genetic diversity and increases the impact of inbreeding, accelerating the path to extinction.

adaptation to edge conditions

Adaptation to edge conditions refers to how well a population can survive in the outer areas of its habitat, which are often less favorable than the core areas. These edge conditions can include different temperatures, food availability, and increased exposure to predators. Populations that are not well adapted to edge conditions are more likely to fall into an extinction vortex. The inability to thrive at the habitat edges can lead to smaller populations and more fragmented habitats, making survival and reproduction even more difficult.

top-level predators

Top-level predators are species that are at the top of the food chain. They play a crucial role in maintaining the balance of ecosystems. Rare, top-level predators are particularly vulnerable to extinction because they often require large territories and specific prey. If these are compromised due to habitat loss or other factors, their populations can decline rapidly. However, being a rare, top-level predator by itself does not necessarily mean the population is in an extinction vortex. The main issue for populations in an extinction vortex is their very low genetic diversity and reduced ability to adapt to changing conditions, not just their status as predators.