In the nineteenth century, Gregor Mendel first determined some basic rules of genetics that have been observed throughout all types of life. No observations have disproved these basic rules of genetics. Charles Darwin developed the idea of biological evolution around the same time, but he was unaware of Mendel’s discoveries in genetics. Over a century later, Darwin’s idea of evolution was modified in order to incorporate Mendel’s rules of genetics along with the other evidence that Darwin had used.