IBDP HL Biology: Natural Selection - Multiple Choice Questions

What is the definition of a gene pool?

• The total number of dominant alleles in a population

• The number of individuals with a specific genotype in a population

• All the genes and their alleles present in a population

• The total number of chromosomes in a population

Which of the following is NOT a factor that affects allele frequency in geographically isolated populations?

• A) Genetic drift

• B) Founder effect

• C) Natural selection

• D) Crossing over during meiosis

Sickle cell anemia is an example of natural selection in human populations because: A) The HbS allele provides resistance to malaria in heterozygous individuals. B) Homozygous recessive individuals (HbS/HbS) have increased survival rates. C) The disease is only found in tropical regions. D) It is a result of artificial selection.

• The HbS allele provides resistance to malaria in heterozygous individuals.

• Homozygous recessive individuals (HbS/HbS) have increased survival rates.

• The disease is only found in tropical regions.

• It is a result of artificial selection.

What is the primary mechanism that changes allele frequencies in a population over generations?

• Mutation

• Natural selection

• Genetic drift

• Gene flow

Which type of selection favors extreme traits and selects against intermediate traits?

• A) Directional selection

• B) Stabilizing selection

• C) Disruptive selection

• D) Artificial selection

The Hardy-Weinberg equation predicts that allele frequencies will remain constant over time if:

• Natural selection is occurring

• The population size is small

• There is no mutation, migration, or selection

• Mating is non-random

Which condition would likely cause a population to deviate from Hardy-Weinberg equilibrium?

• Large population size

• No gene flow

• Random mating

• Selection pressure favoring a specific trait

Why is antibiotic resistance in bacteria an example of natural selection rather than artificial selection?

• A) Bacteria do not reproduce sexually.

• B) Humans do not deliberately choose which bacteria survive.

• C) Antibiotics are naturally occurring substances.

What is the primary goal of artificial selection?

• To increase genetic variation within a population

• To allow natural processes to determine allele frequencies

• To breed individuals with desired traits

• To maintain Hardy-Weinberg equilibrium

All bacterial populations have the same resistance genes.

• True

• False