The study of heredity is called genetics. Genetics is the scientific study of genes and heredity, including how certain qualities or traits are passed from parents to offspring. Geneticists are scientists who study genetics and aim to understand the structure and function of genes. The study of genetics is an important branch of biology because heredity is vital to organisms evolution. The study of genetics as a systematic science began in the 19th century with the work of Gregor Mendel, who discovered the laws governing the inheritance of traits.