Question 1

Which of the following best explains why genetic variation is essential for evolution to occur in a population?

Accepted Answer

Genetic variation allows individuals to adapt to environmental changes, increasing the likelihood of survival and reproduction.

Question 2

In the context of Mendel’s pea plant experiments, which type of genetic variation is illustrated by the flower color being either purple or white?

Accepted Answer

Variation determined by a single gene locus with different alleles producing distinct phenotypes.

Question 3

A population of fruit flies is heterozygous for 14% of its loci. What does this indicate about the genetic variability in the population?

Accepted Answer

There is a significant amount of genetic variation, as many loci have two different alleles present.

Question 4

Refer to the second image (DNA sequence diagram). Why do most nucleotide variations not result in phenotypic variation?

Accepted Answer

Most variations occur in introns or do not change the amino acid sequence of proteins.

Question 5

A base-pair substitution occurs in the coding region of a gene but does not change the amino acid sequence. Which concept explains this phenomenon?

Accepted Answer

The redundancy of the genetic code, where multiple codons can code for the same amino acid.

Question 6

Which scenario best illustrates nonheritable variation, as shown in the third image (caterpillars)?

Accepted Answer

Caterpillars raised on different diets develop different appearances, but their genotypes remain unchanged.

Question 7

Which process is most likely to produce new alleles in a population?

Accepted Answer

Mutation, which changes the nucleotide sequence of DNA.

Question 8

Why can harmful recessive alleles persist in a population for many generations?

Accepted Answer

They are masked in heterozygous individuals by the dominant allele, a phenomenon known as heterozygote protection.

Question 9

Which of the following best describes neutral variation?

Accepted Answer

Differences in DNA sequence that do not confer a selective advantage or disadvantage.

Question 10

Why are mutations in somatic cells generally not passed to offspring in most animals?

Accepted Answer

Only mutations in cell lines that produce gametes can be inherited.

Question 11

Gene duplication can lead to evolutionary innovation. Which real-world example supports this statement?

Accepted Answer

The proliferation of olfactory receptor genes in mammals, allowing detection of a wide range of odors.

Question 12

Why do prokaryotes and viruses generate genetic variation more rapidly than plants and animals?

Accepted Answer

They have shorter generation times and higher mutation rates.

Question 13

Which mechanism does NOT contribute to genetic variation during sexual reproduction?

Accepted Answer

Mutation during DNA replication.

Question 14

A population of bacteria exposed to a single antibiotic quickly develops resistance. Which explanation best fits this scenario?

Accepted Answer

Rapid mutation rates and short generation times allow resistant mutants to proliferate quickly.

Question 15

If a population stopped reproducing sexually and switched to asexual reproduction, what would happen to its genetic variation over time?

Accepted Answer

Genetic variation would decrease, as new combinations of alleles would no longer be produced.

Question 16

Which equation can be used to quantify gene variability in a population?

Accepted Answer

$$	ext{Gene Variability} = \frac{	ext{Number of heterozygous loci}}{	ext{Total number of loci}} 	imes 100\%$$

Question 17

Which of the following is a multi-step mechanism by which sexual reproduction increases genetic variation?

Accepted Answer

Crossing over during meiosis, independent assortment of chromosomes, and random fertilization.

Question 18

A point mutation in a gene encoding a protein does not affect the protein’s function. Which explanation is most plausible?

Accepted Answer

The mutation does not change the amino acid sequence due to the redundancy of the genetic code.

Question 19

Which real-world example demonstrates the impact of environmental influences on phenotype without genetic change?

Accepted Answer

Bodybuilders develop large muscles through training, but do not pass this trait to their offspring.

Genetic Variation and Its Role in Evolution

Study Guide - Practice Questions