Question

Scientist hypothesize that modern cheetahs have experienced two genetic bottlenecks. Scientist estimate the first occurred during the last ice age and the second occurred during a time of rapid agricultural growth. The graph shows the population size before and after the first bottleneck event occurred and just before the second bottleneck event. Select the three statements that explain how bottleneck event 2 may have affected the cheetahs' ability to adapt to variable environmental conditions.

1) There is a decrease in the minimum viable population size.
2) There is a lesser chance of genetic uniformity due to inbreeding.
3) There is a greater chance of the species surviving a genetic disease.
4) There is a decrease in the ability to adapt to environmental changes.
5) There is a greater chance of a harmful recessive gene impacting the population.

Answer 1

The second genetic bottleneck event would decrease the cheetahs' ability to adapt to environmental changes, reduce the minimum viable population size, and increase the chance of harmful recessive genes impacting the population.

Step-by-step explanation:

Effects of a Genetic Bottleneck Event

When considering how the second genetic bottleneck event may have impacted the cheetahs' ability to adapt to variable environmental conditions, several factors come into play. This event would likely lead to a decrease in genetic variation due to the significant reduction in population size. Here's an analysis of the statements provided:

1. There is a decrease in the minimum viable population size: This is true since a bottleneck leads to fewer individuals contributing to the genepool.
2. There is a lesser chance of genetic uniformity due to inbreeding: This statement is incorrect. A bottleneck often increases genetic uniformity due to inbreeding, as a smaller population size means closer genetic relatedness among individuals.
3. There is a greater chance of the species surviving a genetic disease: This is incorrect. Reduced genetic variability often results in an increased chance of the entire population being susceptible to diseases.
4. There is a decrease in the ability to adapt to environmental changes: This is correct, as a genetic bottleneck reduces genetic diversity, which is crucial for adaptation to changing environments.
5. There is a greater chance of a harmful recessive gene impacting the population: This is also correct, as with less genetic variation, previously rare recessive genes may become more common, potentially leading to an increase in the expression of harmful traits.

Therefore, the three statements that accurately explain the impact of the second bottleneck event on the cheetahs are statements 1, 4, and 5.