Problem 5 - Campbell Biology

Question

Application/Analysis Which of the following strategies would most rapidly increase the genetic diversity of a population in an extinction vortex? (A) Establish a reserve that protects the population's habitat. (B) Introduce new individuals transported from other populations of the same species. (C) Sterilize the least fit individuals in the population. (D) Control populations of the endangered population's predators and competitors.

Step-by-Step Solution

Answer

B) Introduce new individuals transported from other populations.

Step 1: Understand the Concept

Genetic diversity refers to the variety of genes within a population. It is crucial for the survival and adaptability of a species.

Step 2: Evaluate Strategy A

Establishing a reserve that protects the population's habitat may help the population survive but does not immediately increase genetic diversity.

Step 3: Evaluate Strategy B

Introducing new individuals from other populations directly adds new genes to the gene pool, thereby increasing genetic diversity quickly.

Step 4: Evaluate Strategy C

Sterilizing the least fit individuals removes genes from the population but does not introduce new genetic material.

Step 5: Evaluate Strategy D

Controlling populations of predators and competitors may improve survival rates but does not directly increase genetic diversity.

Step 6: Select the Best Strategy

Among the provided options, introducing new individuals from other populations (Strategy B) is the most effective method for rapidly increasing genetic diversity.

Key Concepts

Extinction Vortex

An extinction vortex is a downward spiral in which a small population experiences increasing risk of extinction. As the population size diminishes, genetic diversity decreases. This makes the population more vulnerable to factors like diseases and environmental changes. When a population enters an extinction vortex, several interconnected problems arise:

• Inbreeding: Breeding among closely related individuals leads to inbreeding depression, reducing fitness.
• Genetic Drift: Random fluctuations in gene frequencies become more pronounced in small populations, leading to a loss of genetic variation.
• Reduced Adaptability: The population becomes less adaptable to environmental changes due to lack of genetic diversity.

To slow or reverse an extinction vortex, it's vital to increase genetic diversity and population size. Introducing new individuals from other populations, as discussed in the exercise solution, is an effective strategy. This directly adds genetic material, reducing the effects of inbreeding and genetic drift.

Genetic Variation

Genetic variation is the raw material for evolution. It refers to the differences in DNA sequences among individuals in a population. Higher genetic variation increases the chances that some individuals possess traits allowing them to survive and reproduce under changing conditions. Genetic variation arises through:

• Mutations: Random changes in DNA that can introduce new traits.
• Gene Flow: Movement of genes between populations, often through the migration of individuals.
• Sexual Reproduction: Combining genes from two individuals to create genetically unique offspring.

In the context of an extinction vortex, fostering higher genetic variation is crucial. For example, introducing individuals from other populations (gene flow) can rapidly add new genes to the population, enhancing genetic diversity as highlighted in the correct solution to the exercise.

Species Survival

The survival of a species depends on its ability to adapt to its environment. This adaptability is closely linked to genetic diversity. Higher genetic diversity means a greater likelihood that some individuals in a population will have traits that help them survive changes such as climate shifts, new diseases, or habitat alterations. Key strategies for species survival include:

• Maintaining Habitat: Protecting and restoring the natural habitats where species live.
• Promoting Genetic Diversity: Using techniques like translocation to introduce new genetic material into the population.
• Reducing Threats: Managing threats from predators, competitors, and human activities.

By rapidly increasing the genetic diversity as seen in the recommended strategy (introducing new individuals from other populations), we improve the resilience of the population, thus enhancing species survival.

Population Genetics

Population genetics studies the distribution of genes in populations and how they change over time. It helps us understand important concepts like genetic drift, gene flow, and the effects of selection. Some key ideas in population genetics include:

• Genetic Drift: Random changes in gene frequencies, more significant in small populations.
• Gene Flow: Movement of genes between populations, which can introduce new genetic material.
• Natural Selection: Differential survival and reproduction due to traits that offer a survival advantage.

Understanding population genetics helps us develop strategies to combat extinction vortices. For instance, by recommending the introduction of new individuals from other populations, we use gene flow to quickly increase genetic diversity, helping stabilize the genetic structure of endangered populations.