Final answer:
Johann Gregor Mendel laid the foundation for the study of genetics in the mid-1800s, defining key principles of inheritance through his work with pea plants.
Step-by-step explanation:
Johann Gregor Mendel described that the modern field of genetics is based on the principles of inheritance, in the mid-1800s.
Genetics is the study of heredity, which was significantly advanced by the work of Mendel. Before the discovery of chromosomes or the detailed understanding of meiosis, Mendel focused on pea plants and their trait transmission, crafting the groundwork for classical, or Mendelian, genetics. Through his meticulous experiments with large sample sizes, Mendel discovered that traits are passed down from parents to offspring in predictable patterns. He presented his findings on inheritance through traits in Experiments in Plant Hybridization.
The fundamental principles Mendel established include the principle of segregation, the principle of dominance, and the principle of independent assortment. These core concepts paved the way for our contemporary comprehension of genetics and the role of genes, situated on chromosomes, as the essential units of heredity, with evolution and expression capabilities.