Meiosis and Genetic Diversity Flashcards
23 Questions
100 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

What is the average number of crossover events that occurs during meiosis in humans per chromosome pair?

  • Three crossover events
  • One to three crossover events (correct)
  • One crossover event
  • Two crossover events

    • Crossing over produces chromosomes that are identical to one another.

    False

    What effect does random fertilization have on genetic variation?

    It adds to the genetic variation arising from meiosis.

    The main driver of evolutionary changes in a population is _____ success.

    <p>differential reproductive</p> Signup and view all the answers

    What are the possible diploid combinations produced from human gametes due to independent assortment?

    <p>70 trillion</p> Signup and view all the answers

    How does natural selection influence genetic variation?

    <p>Natural selection increases genetic variations that are favored by the environment.</p> Signup and view all the answers

    Sexual reproduction decreases genetic variation in a population.

    <p>False</p> Signup and view all the answers

    Who published a theory of inheritance that helps explain genetic variation?

    <p>Gregor Mendel</p> Signup and view all the answers

    What does heritable information provide for?

    <p>continuity of life.</p> Signup and view all the answers

    How does meiosis generate genetic diversity?

    <p>By crossing over, independent assortment, and random fertilization.</p> Signup and view all the answers

    What type of cells does meiosis ensure the formation of?

    <p>haploid gamete cells.</p> Signup and view all the answers

    What are the two rounds of meiosis called?

    <p>meiosis I and meiosis II.</p> Signup and view all the answers

    What happens to sister chromatids during DNA replication?

    <p>They become genetically identical.</p> Signup and view all the answers

    What is a tetrad?

    <p>A set of four sister chromatids</p> Signup and view all the answers

    What is the benefit of asexual reproduction?

    <p>Rapid population increase</p> Signup and view all the answers

    What does sexual reproduction result in compared to asexual reproduction?

    <p>greater variation of offspring.</p> Signup and view all the answers

    Sperm and ova are ______ cells.

    <p>gametes</p> Signup and view all the answers

    What number of chromosomes are contained in human gametes?

    <p>23</p> Signup and view all the answers

    What type of cells are somatic cells?

    <p>diploid cells.</p> Signup and view all the answers

    What is the function of homologous chromosomes in meiosis?

    <p>They are separated to form haploid cells.</p> Signup and view all the answers

    What occurs during crossing over?

    <p>Sister chromatids exchange portions of DNA.</p> Signup and view all the answers

    Crossing over results in identical chromatids.

    <p>False</p> Signup and view all the answers

    What is the expected number of possible gamete combinations in humans?

    <p>about 8 million.</p> Signup and view all the answers

    Study Notes

    Meiosis and Genetic Diversity

    • Heritable information is essential for continuity of life and genetic diversity.
    • Meiosis produces haploid gametes in sexually-reproducing diploid organisms, halving the chromosome number.
    • Two sequential phases characterize meiosis: meiosis I and meiosis II.
    • Mitosis and meiosis share similarities in chromosome segregation but diverge in daughter cell quantity and genetic content.

    Role of Meiosis in Genetic Inheritance

    • Chromosome replication and separation during meiosis contribute to genetic inheritance.
    • Homologous chromosome pairs, containing one chromosome from each parent, are crucial in diploid cells.
    • Sister chromatids, created during DNA replication, are identical unless replication errors occur.
    • Tetrad formation during prophase I allows crossing over, increasing genetic variation within gametes.

    Asexual vs. Sexual Reproduction

    • Asexual reproduction involves one parent, producing genetically identical offspring.
    • Genetic differences in asexual offspring arise only from mutations during DNA replication.
    • Sexual reproduction, involving two parents, results in genetically diverse offspring with unique traits due to allele combinations.

    Gametes and Chromosomal Composition

    • Gametes (sperm and eggs) are haploid with 23 unpaired chromosomes in humans.
    • Somatic cells are diploid, consisting of two paired chromosome sets, totaling 46 chromosomes in humans.

    Chromosome Mechanics

    • Homologous chromosomes carry genes for the same traits, inherited from both parents.
    • Sister chromatids are identical and remain connected until separated during mitosis or meiosis II.

    Genetic Variation Mechanisms

    • Independent assortment during metaphase I randomly distributes maternal and paternal chromosomes to daughter cells, producing a mix of genetic combinations.
    • In humans, each gamete can represent approximately 8.4 million possible chromosome combinations due to independent assortment.
    • Crossing over in prophase I allows for DNA exchange between sister chromatids, creating new gene combinations and increasing genetic diversity.

    Recombinant Asci in Sordaria fimicola

    • The fungus Sordaria fimicola illustrates genetic variation through haploid cells undergoing meiosis after mycelial fusion.
    • Crossing over observed in the resulting asci leads to diverse patterns of spore colors.

    Evolutionary Implications

    • Genetic variation generated during sexual reproduction is fundamental for species survival and adaptation.
    • Natural selection favors variations better suited to environmental changes, enhancing population resilience.

    Important Figures and Statistics

    • Independent assortment allows for 2^n combinations, where n is the number of haploid chromosome sets.
    • In humans, with 23 chromosomes, the possible gamete combinations is 2^23 (~8.4 million).
    • Crossovers increase the potential combinations even further during meiosis.
    • Fertilization introduces additional variability, creating zygotes with approximately 70 trillion diploid combinations.

    Summary on Genetic Diversity

    • Mechanisms contributing to genetic variation include independent assortment, crossing over, and random fertilization.
    • These processes ensure that offspring inherit unique combinations of traits from both parents, essential for the survival of species in changing environments.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Description

    Explore key concepts related to meiosis and its role in genetic diversity through this set of flashcards. Understand the enduring principles and essential knowledge that underpin the process of meiosis in sexually-reproducing organisms.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser