AP Biology : Understanding Genetic Drift, Bottleneck Effect, and Founder Effect
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Example Question #44 : Population Genetics
A population of wolves is living in an area when a tornado strikes and kills most of the wolves. The population of the wolves has been greatly reduced. Which of the following best describes the impact of the disaster on the genetic makeup of the population of wolves?
Cannot be determined from the information
Gene flow
Hardy-Weinberg principle
Bottleneck effect
Founder effect
Bottleneck effect
The Bottleneck effect happens when an event occurs that drastically reduces the population of a species. The remaining individuals most likely do not represent the genetics of the population before the catastrophic event, since it becomes a much smaller sample size.
Example Question #21 : Understanding Genetic Drift, Bottleneck Effect, And Founder Effect
There was once a population on planet M311, called the Freg, who lived on a planet not unlike Earth. At the height of the Fregs technology and evolution, a collection of asteroids bombarded the planet and the devastation was so great that the planet was split in two, as was the Freg population. Much of the Freg population died, but many still survived on both pieces of M311.
The asteroid was an enormous catastrophe that drastically reduced the Freg population. As a result, their gene pool will be significantly smaller. What is this phenomenon called?
The Bottleneck Effect
The Darwin Conundrum
The Extinction Example
The Dinosaur Hypothesis
Radical Genetecism
The Bottleneck Effect
The bottleneck effect is the correct answer here. The effect is defined as a sharp reduction in a populations size due to an environmental effect. In this scenario, the asteroids were the environmental effect and it caused the Freg population to decrease significantly. Also, none of the other answers are real theories.
Example Question #22 : Understanding Genetic Drift, Bottleneck Effect, And Founder Effect
Which of the following is true of genetic drift?
The effects of genetic drift are negligible in smaller populations
Genetic drift helps reduce the frequency of harmful alleles in a population
Genetic drift involves the random change of allele frequencies in a population
None of these statements are true
Genetic drift only occurs in populations at Hardy-Weinberg equilibrium
Genetic drift involves the random change of allele frequencies in a population
Genetic drift is a direct result of independent assortment. Since genes are not inherited by any organized mechanism, there are random fluctuations during which certain alleles experience an increase in frequency over others.
Genetic drift results in random changes in allele frequency; these changes are not a cause of genetic drift. In smaller populations and extreme cases, random changes can result in the loss of an allele entirely within the population. The results of genetic drift are more prominent in smaller populations due to their already reduced gene pool. Since genetic drift is random, both beneficial and harmful alleles can be promoted or eliminated.
Genetic drift cannot increase genetic diversity. The only way to increase genetic diversity is by the introduction of new traits and alleles. Genetic drift can reduce genetic diversity by eliminating alleles from a population, but is incapable of creating new traits. This can only be done through mutation.
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