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Multiple Choice
Why is meiosis necessary in sexually reproducing organisms?
A
To produce genetically identical cells for growth and repair
B
To reduce the chromosome number by half, creating haploid gametes
C
To increase the chromosome number in somatic cells
D
To ensure that all offspring are genetically identical to the parents
Verified step by step guidance
1
Understand the purpose of meiosis: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in the production of haploid gametes (sperm and eggs). This is crucial for maintaining the species' chromosome number across generations.
Recognize the difference between haploid and diploid cells: Diploid cells contain two sets of chromosomes, one from each parent, while haploid cells contain only one set. Meiosis ensures that gametes are haploid, so when fertilization occurs, the resulting zygote is diploid.
Identify the stages of meiosis: Meiosis consists of two consecutive divisions, meiosis I and meiosis II. Meiosis I separates homologous chromosomes, and meiosis II separates sister chromatids, ultimately producing four genetically diverse haploid cells.
Consider genetic variation: Meiosis introduces genetic variation through processes like crossing over and independent assortment. Crossing over occurs during prophase I, where homologous chromosomes exchange genetic material, and independent assortment occurs during metaphase I, where chromosomes are randomly distributed into daughter cells.
Reflect on the importance of genetic diversity: Genetic diversity is vital for the survival and adaptation of species. Meiosis contributes to this diversity, ensuring that offspring have unique genetic combinations, which can enhance their ability to adapt to changing environments.