Final answer:
Sexual reproduction and meiosis generate genetic variety through random fertilization, independent assortment, and crossing over, all of which contribute to genetic diversity.
Step-by-step explanation:
Sexual reproduction and meiosis generate genetic variety through multiple mechanisms, specifically:
Random fertilization
Independent assortment
Crossing over
Each of these processes contributes to the genetic diversity seen in sexually reproducing organisms.
Independent assortment refers to how chromosomes are distributed into gametes during meiosis, resulting in over 8 million possible chromosome combinations in humans.
During this phase, chromosomes inherited from either parent can sort into any gamete, creating a vast potential for genetic variation. ]
Crossing over further enhances genetic diversity by exchanging DNA between homologous chromosomes, leading to unique chromosome combinations.
Finally, random fertilization increases variation as it involves the union of any one sperm with any one egg, each with a distinct combination of chromosomes, resulting in over 64 trillion potential combinations for each couple, not even including variations from crossing over.