Significance of Meiosis, Definition, Features, Types and Significance

Significance of Meiosis lies in its crucial role in sexual reproduction and genetic diversity. This process not only produces gametes—sex cells necessary for reproduction—but also ensures the maintenance of the species-specific chromosome number across generations. The significance of meiosis is crucial for students preparing for the NEET exam and is an important topic within the NEET biology syllabus .

Meiosis Definition

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Types of Meiosis

• Gametic Meiosis : This type occurs in diploid cells to produce haploid gametes. The haploid cells generated through gametic meiosis are essential for sexual reproduction , as they fuse during fertilization to restore the diploid chromosome number.
• Zygotic Meiosis: In haploid organisms such as algae and fungi, meiosis occurs in the zygote, which is the fertilized cell. This process results in the production of haploid cells that develop into young haploid organisms, contributing to the life cycle of these organisms.
• Sporic Meiosis: Found in plants like bryophytes, sporic meiosis occurs in the diploid cells of the sporophyte's capsule. This division leads to the production of haploid spores, which can germinate and develop into haploid gametophytes. This alternation of generations is a critical aspect of plant reproduction.

Features of Significance of Meiosis

• Two Divisions : Meiosis consists of two stages—meiosis I (reductional division) and meiosis II (equational division).
• Meiosis I : Reduces the chromosome number by half; homologous chromosomes pair and exchange genetic material through recombination.
• Meiosis II : Resembles mitosis; separates sister chromatids, producing four haploid daughter cells.
• Genetic Recombination : Increases genetic diversity through the exchange of genetic material between homologous chromosomes.
• Nondisjunction : Failure of chromosome separation in anaphase I can lead to gametes with abnormal chromosome numbers, causing genetic disorders like trisomy or monosomy.

Significance of Meiosis

• Formation of Gametes : Meiosis produces sex cells (gametes) necessary for sexual reproduction.
• Activates Genetic Information : Activates genes for sex cell development and deactivates sporophytic genes.
• Maintains Chromosome Number : Halves chromosomes to maintain a constant number, preventing doubling after fertilization.
• Independent Assortment : Randomly distributes maternal and paternal chromosomes, reshuffling traits.
• Genetic Mutation: Mutations from meiotic irregularities can lead to genetic variation, with beneficial mutations passed through natural selection.
• Crossing Over : Creates new combinations of traits, increasing genetic diversity and variation.

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MCQs of Significance of Meiosis

Q1. Meiosis is evolutionary significant because it results in:-

1. Genetically similar daughters
2. Four daughter cells
3. Eggs and sperms
4. Recombination

Q2.  Meiosis II is:

1. reductional
2. Equational
3. Both (1) and (2)
4. None of these

Q3. The maximum number of meiosis required to produce 40 seeds are;

1. 50
2. 100
3. 40
4. 20

Answers of MCQs of Significance of Meiosis