Multiple Choice
An earthquake hits a small island. All but a small group of closely related lizards are eliminated, and the survivors spread out over the island. This is an instance of __________.
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22. Evolution of Populations
Genetic Variation
Multiple Choice
The lethal genetic disorder Tay-Sachs disease occurs in individuals with two copies of a recessive allele of the responsible gene. Which of the following statements is true?
A
Because homozygous recessive individuals die, the recessive allele will eventually be lost from the population.
B
Only homozygous dominant individuals will be able to survive and reproduce.
C
In the heterozygous condition, the dominant allele will overcome the recessive allele and only the dominant allele will be passed on to offspring.
D
Homozygous dominant individuals will be more likely to reproduce than heterozygous individuals.
E
Heterozygous individuals will survive and may pass the recessive allele on to their offspring.
Verified step by step guidance1
Understand the genetic basis of Tay-Sachs disease: It is caused by a recessive allele, meaning that an individual must have two copies of this allele (homozygous recessive) to express the disease.
Recognize that individuals with one dominant and one recessive allele (heterozygous) do not express the disease but can carry the recessive allele.
Consider the genetic inheritance: Heterozygous individuals can pass on either the dominant or the recessive allele to their offspring.
Evaluate the statement: 'Heterozygous individuals will survive and may pass the recessive allele on to their offspring.' This is true because heterozygous individuals do not express the disease and can reproduce, potentially passing the recessive allele to the next generation.
Conclude that the recessive allele can persist in the population through heterozygous carriers, even if homozygous recessive individuals do not survive to reproduce.
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