Final answer:
Mendel's experiments with crossing yellow and green seed pea plants illustrated the principle of dominance, where the yellow seed trait appeared in all F1 offspring. His work led to the discovery of the principles of segregation and independent assortment, critical foundations of genetic inheritance.
Step-by-step explanation:
Mendel's experiments with pea plants demonstrated fundamental genetic principles. When crossing plants with yellow seeds and green seeds, the result was offspring with only yellow seeds, illustrating the principle of dominance. In this example, the yellow seed color is a dominant trait over the recessive green seed color. Mendel's further experiments led to the 3:1 ratio observed in the F2 generation when these hybrids were crossed, indicating the presence of the recessive trait that did not appear in the F1 generation but reemerged in the subsequent generation.
The experiments were methodical, where Mendel first identified true-breeding plants (P1 generation) and then performed monohybrid crosses between plants with distinct traits. The principle of segregation was discovered through this method, demonstrating that traits are inherited as discrete units. Also, the principle of independent assortment was formulated through dihybrid crosses involving multiple traits, showing that alleles for different traits are sorted independently of one another during gamete formation, contributing to genetic diversity.
These three principles laid down by Mendel's work—the principles of segregation, dominance, and independent assortment—are fundamental to our understanding of heredity and genetics.