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Questions and Answers
What is meant by evolution?
What is meant by evolution?
What is the term for the failure of homologous chromosomes to separate properly during meiosis?
What is the term for the failure of homologous chromosomes to separate properly during meiosis?
In a population at Hardy-Weinberg equilibrium, if the frequency of the dominant allele is 0.6, what is the frequency of the recessive phenotype?
In a population at Hardy-Weinberg equilibrium, if the frequency of the dominant allele is 0.6, what is the frequency of the recessive phenotype?
What does the litter of bunnies indicate about the genotype of the male rabbit with normal ears and the female with floppy ears?
What does the litter of bunnies indicate about the genotype of the male rabbit with normal ears and the female with floppy ears?
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What does Mendel's Law of Independent Assortment state?
What does Mendel's Law of Independent Assortment state?
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Which of the following is not a source of genetic variation in sexual reproduction?
Which of the following is not a source of genetic variation in sexual reproduction?
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What are the specific products of meiosis I?
What are the specific products of meiosis I?
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What is meant by divergent evolution?
What is meant by divergent evolution?
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What is the main distinction between genotype and phenotype?
What is the main distinction between genotype and phenotype?
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In Mendel's pea plant experiments, what was the primary focus of his observations?
In Mendel's pea plant experiments, what was the primary focus of his observations?
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What genetic phenomenon does albinism in mammals, caused by a gene blocking another gene's pigment production, illustrate?
What genetic phenomenon does albinism in mammals, caused by a gene blocking another gene's pigment production, illustrate?
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Which of the following accurately defines a recessive trait?
Which of the following accurately defines a recessive trait?
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Which structure is NOT appropriately matched with its corresponding letter as shown in a genomic diagram?
Which structure is NOT appropriately matched with its corresponding letter as shown in a genomic diagram?
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In the context of genetics, what is hybrid vigor?
In the context of genetics, what is hybrid vigor?
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How can epistasis affect the expression of phenotypic traits?
How can epistasis affect the expression of phenotypic traits?
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Which of the following is an example of Mendelian inheritance?
Which of the following is an example of Mendelian inheritance?
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What is the primary source of genetic variation in asexual and sexual reproduction?
What is the primary source of genetic variation in asexual and sexual reproduction?
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From the cross BbTt × BBtt, what fraction of the progeny would have black fur and long tails?
From the cross BbTt × BBtt, what fraction of the progeny would have black fur and long tails?
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What phenomenon describes the reduction in genetic diversity due to a significant population decrease?
What phenomenon describes the reduction in genetic diversity due to a significant population decrease?
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Which factor is essential for natural selection to occur?
Which factor is essential for natural selection to occur?
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Which of the following best defines crossing over?
Which of the following best defines crossing over?
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Which trait represents an example of an analogous trait?
Which trait represents an example of an analogous trait?
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What is the outcome of fertilization regarding ploidy?
What is the outcome of fertilization regarding ploidy?
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During which stage of meiosis does crossing over typically occur?
During which stage of meiosis does crossing over typically occur?
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What mode of inheritance is indicated by a cross that does not produce any blended offspring?
What mode of inheritance is indicated by a cross that does not produce any blended offspring?
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How many chromosomes are present in a gamete from a diploid canine cell with 38 pairs of autosomes?
How many chromosomes are present in a gamete from a diploid canine cell with 38 pairs of autosomes?
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If the frequency of homozygous dominant individuals in a population is 0.49, what percentage of the population are carriers?
If the frequency of homozygous dominant individuals in a population is 0.49, what percentage of the population are carriers?
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Which of the following is NOT an assumption of Hardy-Weinberg equilibrium?
Which of the following is NOT an assumption of Hardy-Weinberg equilibrium?
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Which phase of meiosis occurs when sister chromatids are separated?
Which phase of meiosis occurs when sister chromatids are separated?
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Study Notes
Evolution
- Descent with modification is a key concept in evolutionary theory, meaning organisms change over time.
- Evolution is supported by scientific evidence and it's not merely a theory.
Meiosis
- Nondisjunction occurs when homologous chromosomes fail to separate during meiosis I.
- Meiosis I results in two genetically unique daughter cells, each with half the number of chromosomes as the parent cell.
Hardy-Weinberg Equilibrium
- The frequency of the recessive phenotype (q²) in a population is calculated using the Hardy-Weinberg equation.
- When the dominant allele frequency (p) is 0.6, the recessive allele frequency (q) is 0.4, and the recessive phenotype frequency (q²) is 0.16.
Genetics
- Heterozygous means having two different alleles for a trait.
- Mendel's Law of Independent Assortment states that alleles for different traits segregate independently of each other during gamete formation.
- Mutation is a primary source of genetic variation in both asexual and sexual reproduction.
- Crossing over is a process that occurs during prophase I of meiosis and involves the exchange of genetic material between homologous chromosomes.
- Divergent evolution occurs when species with similar characteristics evolve from a shared common ancestor.
Inheritance
- A cross between a BbTt (black fur, short tail) and BBtt (black fur, long tail) mouse would result in 50% of the offspring having black fur and long tails.
- Genetic drift happens when random events cause changes in allele frequencies within a population.
- Bottleneck effect is a type of genetic drift where a population drastically reduces in size, causing a loss of genetic diversity.
- Natural selection acts on heritable variation within a population, leading to adaptations.
- Fertilization combines two haploid gametes to form a diploid zygote, increasing ploidy.
Analogous Traits
- Wings in bats and birds are analogous traits, meaning they serve a similar function but evolved independently.
Karyotype
- A karyotype is a visual representation of an individual's chromosomes.
- A somatic cell is a non-reproductive cell.
- A diploid organism has two sets of chromosomes.
- A gamete, or sex cell, is haploid with one set of chromosomes.
Chromosomal Alterations
- Inversions occur when a segment of a chromosome detaches, rotates 180 degrees, and reattaches.
Mitosis vs Meiosis
- Both mitosis and meiosis involve the separation of sister chromatids.
- Meiosis results in increased genetic diversity, while mitosis produces genetically identical daughter cells.
Punnett Square
- A Punnett square is a diagram used to predict the genotype and phenotype of offspring from a cross.
- For a cross between Aa and Aa, the box labeled 4 would contain the genotype aa.
Modes of Inheritance
- Incomplete dominance occurs when the heterozygous phenotype is a blend of the two homozygous phenotypes.
- Codominance occurs when both alleles are equally expressed in the heterozygous phenotype.
- Polygenic inheritance involves multiple genes contributing to a single trait.
- Complete dominance occurs when one allele completely masks the other allele.
Gametes
- A canine gamete will have 19 chromosomes (38 autosomes + 1 sex chromosome).
Hardy-Weinberg Equilibrium in Populations
- If the frequency of homozygous dominant individuals (p²) is 0.49, the frequency of carriers (2pq) is 42%.
- In a population of 1000 individuals with 250 exhibiting the recessive phenotype, the frequency of the recessive allele (q) is 0.5.
Asexual Reproduction
- Asexual reproduction doesn't produce genetic diversity, unlike sexual reproduction.
Karyotype Analysis
- A karyotype with only one sex chromosome indicates a monosomy.
Probability of Offspring
- The probability of an offspring being heterozygous for all four loci from the cross AaBBccDd x aaBbCcDd is 1/16.
Lamarck's Theory
- Lamarck's theory of acquired inheritance proposed that traits acquired during an individual's lifetime were passed on to offspring, which has been disproven.
Mendel's Experiments
- Mendel's experiments involved studying the inheritance of traits in pea plants by crossing plants with different traits and observing the offspring over multiple generations.
Epistasis
- Epistasis is a genetic interaction where one gene masks the expression of another gene, as seen in albinism.
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Description
Explore key concepts in evolutionary biology, including descent with modification and the Hardy-Weinberg equilibrium. This quiz covers important topics in meiosis, genetics, and how traits are inherited. Test your understanding of these foundational ideas in biology.
