Question: which preservationist was instrumental in establishing a national park to protect yosemite valley
Answer: John Muir ( / mjʊər / ; April 21 , 1838 -- December 24 , 1914 ) also known as `` John of the Mountains '' and `` Father of the National Parks '' , was an influential Scottish - American naturalist , author , environmental philosopher , glaciologist and early advocate for the preservation of wilderness in the United States .