How does meiosis impact evolutionary processes?

Meiosis contributes to evolutionary processes by increasing genetic variation through recombination and independent assortment.

Meiosis is a type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell. This process is crucial for sexual reproduction in eukaryotes, including humans. The key aspect of meiosis that impacts evolution is the generation of genetic diversity.

During meiosis, two important processes occur: crossing over (or recombination) and independent assortment. In crossing over, homologous chromosomes exchange genetic material. This means that the genes from the mother and father can mix, creating new combinations of traits. Independent assortment, on the other hand, refers to the random distribution of maternal and paternal chromosomes into gametes. This ensures that each gamete (and therefore each offspring) will have a unique combination of traits.

These processes increase genetic variation within a population. Genetic variation is the raw material for evolution. When the environment changes, it may favour certain traits over others. If these traits are present in the population due to genetic variation, individuals with these traits are more likely to survive and reproduce. This is the process of natural selection, which leads to evolution.

Moreover, meiosis also ensures the constant chromosome number across generations. Without meiosis, the chromosome number would double each generation, which is not sustainable. By halving the chromosome number in the sex cells, meiosis allows for the fusion of two sex cells (fertilisation) to restore the original chromosome number in the offspring.

In summary, meiosis plays a crucial role in evolution by increasing genetic variation, providing the raw material for natural selection, and maintaining a constant chromosome number across generations.