Final answer:
The Law of Independent Assortment, Mendel's Second Law, states that different genes segregate into gametes independently, except when they are linked on the same chromosome. Mendel's dihybrid crosses in pea plants showed a 9:3:3:1 phenotypic ratio, illustrating this principle and the genetic diversity it allows.
Step-by-step explanation:
Law of Independent Assortment
The Law of Independent Assortment, also referred to as Mendel's Second Law, explains how genes for different traits are passed down from parents to offspring independently of one another. According to this principle, the inheritance pattern of one trait does not affect the inheritance pattern of another, which means that the alleles for one gene segregate into gametes independently of the alleles for another gene. This is true except for genes that are linked on the same chromosome. Mendel's experiments with pea plants, specifically dihybrid crosses between plants with two different traits such as seed color and seed texture, illustrated this principle. The associated ratio Mendel found when he mixed two traits was a phenotypic ratio of 9:3:3:1, which demonstrates the independent assortment of genes.
Each gene pair segregates independently unless they are linked, which means they are located on the same chromosome. This leads to a significant degree of genetic diversity because of the numerous combinations of alleles that can occur. Mendel observed this in his experiments with pea plants, noting the varied outcomes that were possible due to independent assortment.