John Ray, Ray also spelled (until 1670) Wray, (born Nov. 29, 1627, Black Notley, Essex, Eng.—died Jan. 17, 1705, Black Notley), leading 17th-century English naturalist and botanist who contributed significantly to progress in taxonomy. His enduring legacy to botany was the establishment of...
Edward L. Tatum American biochemist who helped demonstrate that genes determine the structure of particular enzymes or otherwise act by regulating specific chemical processes in living things. His research helped create the field of molecular genetics and earned him (with George Beadle and Joshua
Joseph Walker was a U.S. fur trader and explorer. He led the first group of white men to make the east-to-west journey over the Sierra Nevada mountains. He also forged a new…