Final answer:
Crossing over in meiosis is the exchange of genetic material between non-sister chromatids of homologous chromosomes, contributing to genetic diversity in sexually reproducing organisms.
Step-by-step explanation:
The phenomenon of crossing over in meiosis refers to the exchange of genetic material between non-sister chromatids of homologous chromosomes during prophase I of meiosis. This process significantly contributes to the genetic diversity of gametes. Crossing over creates new combinations of genes, as segments of DNA are swapped, allowing for a mix of maternal and paternal traits in offspring.
Within the context of Mendel's laws, particularly the law of independent assortment, this exchange of genetic material underpins the phenomenon where different traits are inherited separately from each other. As a result, genetic recombination occurs, providing an explanation for the variation observed in the offspring from sexually reproducing organisms.