Final answer:
Pierre Louis Moreau de Maupertuis was the scientist who worked on garden peas before Mendel. Mendel is renowned for discovering the fundamental laws of inheritance through his experiments with pea plants, outlining dominant and recessive trait patterns.
Step-by-step explanation:
The scientist who worked on garden peas before Gregor Mendel was Pierre Louis Moreau de Maupertuis. Although Mendel is known as the father of modern genetics for his pivotal work with pea plants, Maupertuis made earlier contributions to the understanding of heredity. Mendel's work was particularly significant as he demonstrated that physical characteristics are transmitted to subsequent generations in discrete and predictable patterns, which he showed through his meticulous experiments with pea plants. He discovered what we now call Mendel's laws, including the concepts of dominant and recessive traits.