Podcast
Questions and Answers
What are the basic components of the Hardy-Weinberg model?
What are the basic components of the Hardy-Weinberg model?
Frequencies of two alleles in a gene pool before and after many random matings.
Which of the following statements is not a part of the Hardy-Weinberg principle?
Which of the following statements is not a part of the Hardy-Weinberg principle?
The genotype frequencies in the offspring generation must add up to two.
The Hardy-Weinberg model makes the following assumptions: no selection at the gene in question; no genetic drift; no gene flow; no mutation; random mating.
The Hardy-Weinberg model makes the following assumptions: no selection at the gene in question; no genetic drift; no gene flow; no mutation; random mating.
True (A)
What is the frequency of the A1A2 genotype in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals?
What is the frequency of the A1A2 genotype in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals?
What is the frequency of the A1 allele in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals?
What is the frequency of the A1 allele in a population composed of 20 A1A1 individuals, 80 A1A2 individuals, and 100 A2A2 individuals?
Which evolutionary force consistently results in adaptive changes in allele frequencies?
Which evolutionary force consistently results in adaptive changes in allele frequencies?
What genotype frequencies are expected under Hardy-Weinberg equilibrium for a population with allele frequencies of p = 0.8 and q = 0.2?
What genotype frequencies are expected under Hardy-Weinberg equilibrium for a population with allele frequencies of p = 0.8 and q = 0.2?
Which evolutionary force could create new genetic information in a population?
Which evolutionary force could create new genetic information in a population?
If 70% of the gametes produced in a fruit fly population contain the A1 allele, what proportion of the flies carry both A1 and A2?
If 70% of the gametes produced in a fruit fly population contain the A1 allele, what proportion of the flies carry both A1 and A2?
The original source of all genetic variation is _____ .
The original source of all genetic variation is _____ .
Which of the following are causes of evolutionary change?
Which of the following are causes of evolutionary change?
Generation-to-generation change in the allele frequencies in a population is _____ .
Generation-to-generation change in the allele frequencies in a population is _____ .
What is an example of a homozygous genotype?
What is an example of a homozygous genotype?
All the genes in a population are that population's _____.
All the genes in a population are that population's _____.
Genetic drift is a process based on _____.
Genetic drift is a process based on _____.
A mutation occurs when _____.
A mutation occurs when _____.
How will the removal of tall individuals affect the human population?
How will the removal of tall individuals affect the human population?
Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans.
Modern travel along with migration reduces the probability of _____ having an effect on the evolution of humans.
The ease with which humans travel across the globe is likely to increase _____.
The ease with which humans travel across the globe is likely to increase _____.
Homologous pairs of chromosomes are lined up independently of other such pairs during _____.
Homologous pairs of chromosomes are lined up independently of other such pairs during _____.
Crossing over, resulting in an increase in genetic variation, occurs between _____.
Crossing over, resulting in an increase in genetic variation, occurs between _____.
In human gamete production, what is the average number of crossover events per chromosome pair?
In human gamete production, what is the average number of crossover events per chromosome pair?
Which of these gametes contain one or more recombinant chromosomes?
Which of these gametes contain one or more recombinant chromosomes?
In a hypothetical population of 200 cats composed of two alleles TL and TS, which statements about the population are true?
In a hypothetical population of 200 cats composed of two alleles TL and TS, which statements about the population are true?
Enter the values for the expected frequency of each genotype for TLTL, TLTS, and TSTS.
Enter the values for the expected frequency of each genotype for TLTL, TLTS, and TSTS.
In a hypothetical population of 300 wolves, which statements accurately describe the population?
In a hypothetical population of 300 wolves, which statements accurately describe the population?
According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool.
According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool.
How can you calculate the frequency of each allele in a small population of beetles?
How can you calculate the frequency of each allele in a small population of beetles?
What are the three major mechanisms of evolution?
What are the three major mechanisms of evolution?
What percentage of a North American population is heterozygous for cystic fibrosis, assuming Hardy-Weinberg equilibrium?
What percentage of a North American population is heterozygous for cystic fibrosis, assuming Hardy-Weinberg equilibrium?
Rabbit ear size tends to decrease as latitude increases. This is an example of _____.
Rabbit ear size tends to decrease as latitude increases. This is an example of _____.
What genotypes would you expect to find in the offspring of two Rr parents?
What genotypes would you expect to find in the offspring of two Rr parents?
In a population of flowers with allele frequencies of 80% CR and 20% CW, what are the expected proportions of genotypes?
In a population of flowers with allele frequencies of 80% CR and 20% CW, what are the expected proportions of genotypes?
If a population is in Hardy-Weinberg equilibrium, what has to happen for allele and genotype frequencies to change?
If a population is in Hardy-Weinberg equilibrium, what has to happen for allele and genotype frequencies to change?
Which type of selection tends to increase genetic variation?
Which type of selection tends to increase genetic variation?
In a bell-shaped curve, what does the x-axis represent?
In a bell-shaped curve, what does the x-axis represent?
Heterozygote advantage refers to the tendency for heterozygous individuals to have better fitness than homozygous individuals. This results in less genetic variation in the population.
Heterozygote advantage refers to the tendency for heterozygous individuals to have better fitness than homozygous individuals. This results in less genetic variation in the population.
Which kind of selection made giraffes the long-necked creatures they are today?
Which kind of selection made giraffes the long-necked creatures they are today?
Which kind of selection is likely at work regarding the birth weight of babies?
Which kind of selection is likely at work regarding the birth weight of babies?
Which kind of selection acts on beak size in seedcrackers?
Which kind of selection acts on beak size in seedcrackers?
What kind of selection acts on the adult body size of small Aristelliger lizards?
What kind of selection acts on the adult body size of small Aristelliger lizards?
In a hypothetical population of 500 cats, what are the expected proportions of phenotypes?
In a hypothetical population of 500 cats, what are the expected proportions of phenotypes?
Study Notes
Hardy-Weinberg Principle
- Essential for understanding allele frequencies in a population before and after random mating.
- Genotype frequencies in offspring must add up to one, not two.
- Assumptions include no selection, genetic drift, gene flow, mutation, and random mating.
Genotype and Allele Frequencies
- Calculated using the formula for a hypothetical population with specified genotypes.
- Allele frequency results indicate proportion of dominant (A1) and recessive (A2) alleles.
- Expected genotype frequencies can be derived from known allele frequencies.
Evolutionary Mechanisms
- Selection consistently leads to adaptive changes in allele frequencies, improving the population's fitness.
- Genetic drift impacts small populations through random fluctuations in allele frequencies.
- Gene flow allows for new allele introductions, counteracting genetic drift effects.
Genetic Variation
- Mutation is the original source of genetic variation in populations.
- Crossover events during gamete production enhance genetic diversity among offspring.
Population Dynamics
- Microevolution refers to generation-to-generation changes in allele frequencies.
- Conditions violating Hardy-Weinberg equilibrium indicate potential evolution in response to environmental changes.
Selection Types
- Directional selection favors phenotypes with extreme traits; e.g., long necks in giraffes.
- Stabilizing selection narrows the variety of traits, favoring intermediate phenotypes; e.g., birth weights of babies.
- Disruptive selection promotes extreme traits at both ends of the spectrum while eliminating intermediates; e.g., beak sizes in seedcrackers.
Genetic Calculations
- Percentage of heterozygous individuals can be derived from specific allele conditions (e.g., cystic fibrosis).
- Probabilities of offspring genotypes can be calculated using basic Mendelian genetics.
Population Examples
- Real-world scenarios, such as mutations in cat or wolf populations, illustrate principles of phenotype distribution and allele frequency calculation.
- Specific population responses to environmental pressures show the dynamics of selection and gene flow.
Important Terminology
- Gene pool: all genetic information within a population.
- Cline: gradual change in a trait or allele frequency across a geographical gradient.
- Homozygous genotype: individuals with identical alleles for a trait (e.g., AA, aa).
Key Statistics
- Frequency calculations often result in a decimal representation indicating allele distribution within populations.
- Evolutionary changes can be quantified by changes in allele frequency over generations.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of the Hardy-Weinberg model with these flashcards from Campbell's AP Biology, Chapter 23. Each card covers fundamental concepts, including allele frequencies and the principles of genetic equilibrium. Perfect for quick revisions before exams!
