Yosemite National Park a larger national park by 1890, one which encompassed the valley and its surrounding mountains and forests, paving the way for the National Park System. Yosemite is one of the largest and least fragmented habitat blocks in the Sierra Nevada, and the park supports a diversity of plants and animals. The park has an elevation range from and contains five major vegetation zones: chaparral and oak woodland, lower montane forest, upper montane forest, subalpine zone, and alpine. Of California's 7,000 plant species, about 50% occur in the Sierra Nevada and more than 20% are within Yosemite. The park contains suitable
Yosemite National Park the Sherwin (also called the pre-Tahoe), Tahoe, Tenaya, and Tioga. The Sherwin glaciers were the largest, filling Yosemite and other valleys, while later stages produced much smaller glaciers. A Sherwin-age glacier was almost surely responsible for the major excavation and shaping of Yosemite Valley and other canyons in the area. Glacial systems reached depths of up to and left their marks in the Yosemite area. The longest glacier in the Yosemite area ran down the Grand Canyon of the Tuolumne River for , passing well beyond Hetch Hetchy Valley. Merced Glacier flowed out of Yosemite Valley and into the Merced