Final answer:
Sexual reproduction increases genetic variation through crossing-over, independent assortment, and the random union of gametes, which results in offspring with unique genetic combinations.
Step-by-step explanation:
Sexual reproduction is crucial in creating genetic variation within a species. This variation is a result of several mechanisms. Firstly, crossing-over during prophase I of meiosis allows for the exchange of genetic material between homologous chromosomes. Secondly, independent assortment during metaphase I of meiosis ensures that different combinations of paternal and maternal chromosomes are distributed to each gamete. Lastly, the random union of gametes during fertilization combines the genetic material of two individuals, creating offspring with a unique genetic makeup.
Such genetic variation is critical to the survival and evolution of species, allowing populations to adapt to changing environments and resist diseases. While sexual reproduction requires the involvement of both males and females and may produce fewer offspring compared to asexual reproduction, the benefits of increased genetic diversity often outweigh these drawbacks.