Question

The reason for the genetic variation in the population of organisms

• A. Meiosis
• B. Mitosis
• C. Cytokinesis
• D. Karyokinesis

Hint:

Meiosis introduces genetic variation through crossing over and independent assortment, making it essential for sexual reproduction and evolution in populations.

Answer 1

The Correct Option is A

This question asks for the primary reason for genetic variation in a population of organisms. Genetic variation refers to the differences in genetic makeup among individuals within a population, which is essential for evolution and adaptation. Let’s analyze each option to determine which process contributes to genetic variation. - Meiosis: Meiosis is the process of cell division that produces gametes (sperm and egg cells) in sexually reproducing organisms. It occurs in two stages (Meiosis I and Meiosis II) and results in four haploid cells from a single diploid cell. Meiosis introduces genetic variation through two key mechanisms: (i) Crossing over during prophase I, where homologous chromosomes exchange genetic material, creating new combinations of alleles, and (ii) Independent assortment during metaphase I, where homologous chromosomes are randomly distributed to daughter cells, leading to different combinations of maternal and paternal chromosomes. These processes ensure that each gamete is genetically unique. When gametes fuse during fertilization, the resulting offspring inherit a unique combination of genetic material, leading to genetic variation in the population. Therefore, meiosis is a primary source of genetic variation. - Mitosis: Mitosis is the process of cell division that produces two genetically identical daughter cells from a single parent cell. It is involved in growth, repair, and asexual reproduction in some organisms. During mitosis, the genetic material is replicated and equally distributed to the daughter cells, with no mechanisms like crossing over or independent assortment to introduce variation. While mutations can occur during DNA replication in mitosis, these are rare and not a primary source of genetic variation in populations. Therefore, mitosis does not significantly contribute to genetic variation. - Cytokinesis: Cytokinesis is the process of cytoplasmic division that follows nuclear division (mitosis or meiosis), resulting in the physical separation of daughter cells. It ensures that each daughter cell receives a portion of the cytoplasm and organelles. Cytokinesis does not involve the genetic material directly and does not introduce genetic variation, as it is merely a mechanical process following cell division. Therefore, cytokinesis is not a source of genetic variation. - Karyokinesis: Karyokinesis refers to the division of the nucleus during cell division, encompassing the stages of mitosis or meiosis where the chromosomes are separated into daughter nuclei. While karyokinesis is a part of meiosis (which does contribute to genetic variation), the term itself is more general and can also apply to mitosis, which does not introduce variation. Karyokinesis as a standalone process does not inherently lead to genetic variation; it depends on the type of division (meiosis or mitosis). Therefore, karyokinesis is not the best answer compared to meiosis. Among the options, meiosis is the process that directly and consistently introduces genetic variation in populations through crossing over and independent assortment, followed by sexual reproduction. Mitosis, cytokinesis, and karyokinesis do not play a significant role in generating genetic variation in populations. Thus, the correct answer is Meiosis.

Answer 2

Genetic variation in the population of organisms primarily arises due to meiosis.
Meiosis is a special type of cell division that occurs in sexually reproducing organisms to produce gametes (sperm and egg cells).

During meiosis, several key events contribute to genetic variation:
1. Independent Assortment: Homologous chromosome pairs align randomly at the metaphase plate during meiosis I,
resulting in different combinations of maternal and paternal chromosomes segregating into the gametes.
This means each gamete contains a unique set of chromosomes.

2. Crossing Over (Recombination): In prophase I of meiosis, homologous chromosomes exchange genetic material through crossing over.
This exchange of segments between non-sister chromatids creates new allele combinations on each chromosome.

3. Random Fertilization: The fusion of two gametes from genetically different parents further increases variation,
because the resulting offspring inherits a unique combination of genes.

Genetic variation is essential for the survival and evolution of species as it provides the raw material for natural selection.
Populations with higher genetic diversity are better equipped to adapt to changing environments and resist diseases.

Therefore,
meiosis is the fundamental biological process responsible for creating genetic variation by reshuffling genetic information during gamete formation.