Question

Meiosis is crucial to the survival of sexually reproducing organisms because it not only maintains the proper chromosome number at fertilization, but it also allows for genetic diversity and adaptation.

(a) Describe how the events of meiosis ensure that each new cell will have exactly one member of each pair of paternal chromosomes in the haploid cell.
(b) Describe the meiotic events that make genetic variation possible.

Answer 1

Meiosis ensures that each new cell receives one member of each pair of paternal chromosomes by pairing homologous chromosomes, exchanging genetic material through crossing over, and separating the homologous chromosomes.

Step-by-step explanation:

Events of Meiosis Ensuring Single Member of Each Parental Chromosome Pair in Haploid Cell:

Meiosis consists of two divisions—meiosis I and meiosis II. During meiosis I, homologous chromosomes pair up and exchange genetic material in a process called crossing over. This creates new combinations of alleles on the chromosomes. After crossing over, the homologous chromosomes separate, and each new cell receives one member of each pair of paternal chromosomes. In meiosis II, the sister chromatids separate, resulting in haploid cells that each have one member of each pair of chromosomes.

Meiotic Events that Make Genetic Variation Possible:

Genetic variation is introduced during meiosis through two main processes: crossing over and independent assortment. Crossing over occurs during prophase I, when homologous chromosomes exchange genetic material. This generates new combinations of alleles on the chromosomes. Independent assortment occurs during metaphase I, when the homologous pairs of chromosomes line up randomly at the equator of the cell. This results in a random distribution of maternal and paternal chromosomes into the daughter cells, further increasing genetic diversity.