Evolutionary Factors: Mutation, Gene Flow, Genetic drift, and Natural selection

This is an MCQ-based quiz for GRE on the topic of Evolutionary Factors.

Evolution is the process by which different kinds of a living organisms are believed to have developed from earlier forms during the history of the earth.

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In the Hardy-Weinberg equations, what quantities are represented by the variables p and q?

Allele frequencies Genotype frequencies Expected phenotype frequencies Observed phenotype frequencies

Which of the following variables would not be observed in a population at Hardy-Weinberg equilibrium?

No new mutations are appearing in the population No immigrating organisms are allowed to enter the population The population has a very large number of organisms Females mate with males of the same color to avoid a mixing of colors in the population

Which is not a necessary condition for the Hardy-Weinberg equation to be true?

Small population No mutations in the gene pool Random mating No natural selection No net migration of individuals into or out of the population

Which of the following factors plays the biggest role in the impact of genetic drift on a population?

Immigration of animals Natural selection Mating preferences Random chance

Vertebrates are evolutionarily adapted to terrestial life. Which one of the following adaptations is LEAST likely to contribute to this land-based predominance?

Internal fertilization Internal lungs Short loops of Henle Impermeable outer skin Development of legs

What is the definition of "fitness" in terms of evolution?

The organism's ability to attract the most mates The organism's ability to attain resources while in competition with other organisms of its species The ability of an organism to contribute its genes to future generations The organism's health The ability of an organism to survive its environment

In a certain species of feline, all males are much larger than females. Members of either sex that are of intermediate size struggle to find mates. What principle best describes this phenomenon?

Directional selection Bottleneck effect Disruptive selection Genetic drift Stabilizing selection

Members of a species of red fox have teeth of varying sharpness. Foxes with very sharp teeth are able to kill large prey for food, while foxes with very dull, strong teeth are able to crush eggs and small animals. Foxes with teeth of medium sharpness, however, cannot get food and many die before they are able to reproduce. Over time, the fox population shows a greater proportion of individuals with either very sharp or very dull teeth. Which type of natural selection best describes this situation?

Stabilizing selection Disruptive selection Vestigial selection Directional selection Artificial selection

Which of the following is an example of natural selection?
I. Horses are bred for strength and endurance, and over time, the population of horses is more robust.
II. A late spring storm kills all the young plants in a region, but they are spared outside the storm zone.
III. Ancient ancestors of giraffes instinctively wanted to have longer necks to reach food higher in the trees, leading to the present appearance of giraffes.
IV. A flower that happens to be more attractive to pollinators is more likely to have reproductive success.
V. A mutation of a bacterium caused by exposure to ultraviolet light causes the originally red colonies to be yellow instead.

III

Genetic drift is a phenomenon by which __________ in a population change.

Mutation frequencies

Random mating

Allele frequencies

Natural selection

Quiz/Test Summary

Title: Evolutionary Factors: Mutation, Gene Flow, Genetic drift, and Natural selection

Questions: 10

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