7.2.2 Factors Affecting Allele Frequencies

• A population must have no mutations to be in Hardy-Weinberg equilibrium.


  True
• The Hardy-Weinberg equilibrium states that allele and genotype frequencies remain constant in the absence of evolutionary influences
• For Hardy-Weinberg equilibrium, individuals must mate randomly without preference based on genotypes
• Calculate the allele frequencies for a gene with two alleles, A and a, where A appears 300 times and a appears 200 times in a population of 500 alleles

  1️⃣ Frequency of A = 300 / 500 = 60%

  2️⃣ Frequency of a = 200 / 500 = 40%
• The Hardy-Weinberg equilibrium describes conditions under which allele and genotype frequencies in a population remain constant
• Match the mutation type with its description:

  Point mutations ↔️ Changes in a single base pair

  Frameshift mutations ↔️ Insertion or deletion of nucleotides

  Chromosomal mutations ↔️ Alterations in chromosome structure
• The Hardy-Weinberg equilibrium provides a baseline for measuring how populations evolve over time.

  True
• All genotypes have equal survival and reproduction rates under the condition of no natural selection.


  True
• The Hardy-Weinberg equilibrium requires five conditions to be met.


  True
• The five conditions for Hardy-Weinberg equilibrium ensure that allele frequencies remain stable
• What happens to new alleles under the condition of no mutations in Hardy-Weinberg equilibrium?

  They are not created
• What is the process that introduces new alleles into a population?

  Mutation
• Mutations are essential for genetic variation and adaptation in populations.

  True
• The founder effect occurs when a small group colonizes a new area with a non-representative set of alleles.

  True
• Steps of how natural selection affects allele frequencies

  1️⃣ Certain alleles increase fitness.

  2️⃣ Individuals with beneficial alleles reproduce more.

  3️⃣ Beneficial allele frequencies increase.
• Steps by which natural selection affects allele frequencies

  1️⃣ Fitness: Certain alleles increase an individual's survival and offspring production.

  2️⃣ Reproduction: Individuals with beneficial alleles contribute more to the next generation.

  3️⃣ Allele frequency: Beneficial alleles become more common over time.
• Directional selection favors one extreme phenotype after an environmental change, such as an increase in beak size in finches to crack larger seeds.


  True
• The Hardy-Weinberg equilibrium states that allele and genotype frequencies remain constant in a population unless evolutionary influences are present.


  True
• A large population size is necessary for Hardy-Weinberg equilibrium to minimize random fluctuations in allele frequencies.


  True
• What process introduces new alleles into a population and can alter allele frequencies?

  Mutation
• The process of mutation introduces new alleles into a population during DNA replication
• Genetic drift is a random process that causes changes in allele frequencies
• What is the definition of fitness in evolutionary biology?

  Ability to survive and reproduce
• What is gene flow and how does it affect allele frequencies?

  Movement of alleles between populations
• What are the two types of non-random mating that affect allele frequencies?

  Assortative and disassortative mating
• Assortative mating enhances genetic diversity in a population.

  False
• What does the term "allele frequency" refer to in genetics?

  Proportion of an allele
• Why is a large population size necessary for Hardy-Weinberg equilibrium?

  Minimizes genetic drift
• How is allele frequency calculated in a population?

  Number of times allele appears / total number of alleles
• What does it mean if a population deviates from Hardy-Weinberg equilibrium?

  Evolution is occurring
• What is the role of mutation in allele frequencies?

  Introduces new alleles
• How is allele frequency calculated for a population with 500 total alleles, where allele A appears 300 times?

  300 / 500 = 60%
• What is the term for mating where individuals choose mates without preference based on genotypes?

  Random mating
• What is the Hardy-Weinberg equilibrium principle about?

  Allele frequencies remain constant
• Why is a large population size necessary for Hardy-Weinberg equilibrium?

  Minimizes random fluctuations
• What does the 'no gene flow' condition mean for Hardy-Weinberg equilibrium?

  No migration of individuals
• No mutations and no gene flow are two conditions required for Hardy-Weinberg equilibrium.


  True
• Match the type of mutation with its description:

  Point mutations ↔️ Changes in a single base pair.

  Frameshift mutations ↔️ Insertion or deletion of nucleotides.

  Chromosomal mutations ↔️ Alterations in chromosome number or structure.
• Genetic drift is more pronounced in small populations due to fewer allele copies
• The bottleneck effect reduces genetic diversity due to a sudden reduction in population size.


  True