Nettie Stevens was an American geneticist. She is credited with discovering sex chromosomes which later came to be known as the X and Y chromosomes. In 1994, Nettie Stevens was inducted into the National Women's Hall of Fame.
Popularly known as Snowflake Bentley, US meteorologist and photographer Wilson Bentley had taken the world’s first detailed photographs of snowflakes and had thus pioneered snowflake photomicrography. He thus laid the foundation of the study of atmospheric ice crystal formation. Hailing from a farming family, he spent his entire life on his farm.
Donald J. Cram was an American chemist who won the Nobel Prize in Chemistry in 1987. He shared the award with Charles J. Pedersen and Jean-Marie Lehn and the trio was also responsible for founding the field of host–guest chemistry. Donald J. Cram was also honored with other prestigious awards including the National Medal of Science.
Best known as the pioneer of dendrochronology, or the process of dating of events by analyzing tree rings, A. E. Douglass had also been the director of the University of Arizona’s Steward Observatory. He also worked extensively on Mars and was the first to photograph the zodiacal light.
Renowned paleobotanist Frank Hall Knowlton is remembered for his pioneering study of fossilized plants and geologic climates. He not just taught botany but had also been associated with the U.S. Geological Survey. His interests also included birds, and he contributed to a volume named Birds of the World.