Yellowstone National Park
Yellowstone National Park is a national park located primarily in the U.S. state of Wyoming, though it also extends into Montana and Idaho. Yellowstone was the first national park in the world, and is known for its wildlife and its many geothermal features, especially Old Faithful Geyser, one of the most popular features in the park. It established by the U.S. Congress and signed into law by President Ulysses S. Grant on March 1, 1872. It has many types of ecosystems, but the subalpine forest is dominant. Yellowstone National Park has one of the world's largest petrified forests, trees which were long ago buried by ash and soil and transformed from wood to mineral materials.
The Geology of Yellowstone
Yellowstone National Park covers 2,221,766 acres, which is roughly the size of the state of Connecticut. Most of the park is located in the northwestern corner of Wyoming, but a small portion overlaps that state's boundaries with Montana and Idaho. The park is comprised primarily of high, forested, volcanic plateaus that have been eroded over - the millennia by glaciations and stream flow and that are flanked on the north, east, and south by mountains. Rivers and lakes cover 5 percent of the land area, with the largest water body being Yellowstone Lake at 87,040 acres (35,220 ha; 136.00 sq mi). Yellowstone Lake is the largest high altitude lake in North America. Forests comprise 80 percent of the land area of the park; most of the rest is grassland.
The oldest geologic materials in Yellowstone are Precambrian gneiss and schists (2.7 billion years old) that can be found in the Black Canyon of the Yellowstone River. Eocene Absaroka volcanics (40 to 50 million years old) buried the region in deposits of andesite lava, ash, mud, and debris flows that are thousands of feet thick on the east and northwest sides of the park. These mud and debris flows buried forests and formed the petrified or fossil forests that are now popular park attractions. More recently, during the last two million years, cataclysmic eruptions created three calderas, including the enormous Yellowstone caldera in the center of the park we know today, and produced extensive sheets of rhyolitic ash tuff and lava flows, the most common geologic materials in the park.
The magma under the surface continues to provide a heat source in parts of the park, creating geysers, hot springs, mudpots, and fumaroles, and contributes to the frequent seismic activity in the area. Hidden beneath the region, Yellowstone's volcano is dormant at best; most geologists predict another cataclysmic eruption \soon\
Biology and ecology
Hundreds of species of mammals, birds, fish and reptiles have been documented,
including several that are either endangered or threatened. The vast forests and grasslands also include unique species of plants. Grizzly Bears, wolves, and free-ranging herds of bison and elk live in the park.
Flora
Over 1,700 species of trees and other vascular plants are native to the park. Another 170 species are considered to be exotic species and are non-native. Of the eight conifer tree species documented, Lodgepole Pine forests cover 80% of the total forested areas.
In Yellowstone, about seven percent of the whitebark pine species have been impacted with the fungus, compared to nearly complete infestations in northwestern Montana. Quaking Aspen and willows are the most common species of deciduous trees. The aspen forests have declined significantly since the early 20th century, but scientists at Oregon State University attribute recent recovery of the aspen to the reintroduction of wolves which has changed the grazing habits of local elk.
There are dozens of species of flowering plants that have been identified, most of which bloom between the months of May and September. The Yellowstone Sand Verbena is a rare flowering plant found only in Yellowstone. It is closely related to species usually found in much warmer climates, making the sand verbena an enigma. The estimated 8,000 examples of this rare flowering plant all make their home in the sandy soils on the shores of Yellowstone Lake, well above the waterline.
Fauna
Yellowstone is widely considered to be the finest megafauna wildlife habitat in the lower 48 states. There are almost 60 species of mammals in the park, including the gray wolf, the threatened lynx, and grizzly bears. Other large mammals include the bison (buffalo), black bear, elk, moose, mule deer, white-tailed deer, mountain goat, pronghorn, bighorn sheep and mountain lion.
Grizzly Bears
This is the most formidable predator in the lower 48 states, weighing in at 500 pounds or more. Only Alaska's brown bear and polar bear are larger. Because of widespread persecution by settlers, grizzlies have vanished from most of their original habitat. The last of the great bears were killed in the 1920s and 1930s, except for those in Yellowstone and parts of Montana where they were protected. Now, about 300 grizzlies live in and around Yellowstone. The best place to see grizzlies in Yellowstone is in the Mount Washburn area, in Hayden Valley and in the general vicinity of Fishing Bridge.
Threatened & Endangered Birds
Peregrine falcons reside in Yellowstone from April through October, nesting on large cliffs that overlook rivers or valleys where they prey on songbirds and waterfowl.
These falcons can winter as far south as South America but Yellowstone peregrines are believed to winter in Mexico; none spend the winter here. Widespread use of pesticides contributed significantly to the decline of peregrine populations until the 1970s.
Bald eagle, American national symbol, resides in Yellowstone throughout the year, nesting in large trees close to water. Adult birds are easily recognized by their dark bodies, white head and tail feathers. Their wing span may reach up to 7 feet depending on the individual. Bald eagles are often seen around Yellowstone Lake, where they prey on fish in the summer. They also commonly scavenge the carcasses of animals such as elk and bison that die in late fall to early spring. This is especially apparent on the Northern Range of the park.
Whooping cranes are one of the most endangered birds in North America. Standing more than 4 feet tall on their long, slender legs, the white birds with red/black facial markings and black wing tips are named for their unique whooping call. Historical accounts show very few records in western Wyoming and evidence of whooping cranes historically nesting in the park is sketchy at best. When visiting the park, one should not confuse the white whooping cranes with the duller, greyer, rusty sandhill crane. Sandhill cranes frequent the small meadows of the park.
http://en.wikipedia.org/wiki/Yellowstone_National_Park http://www.yellowstonenationalpark.com
1. Yellowstone National Park was established by the U.S. Congress and signed into law by President Ulysses S. Grant on __________. A. March 1, 1872 B. May 1, 1877 C. March 7, 1883 D. April 20, 1890
2. How many species of tree in the Yellowstone Park are considered to be alien plants? A. 700 B. 1,700 C. 170 D. 300
3. The largest predators in America are __________. A. Grizzly bears
B. Alaska's brown bears and polar bears C. gray wolves D. whooping cranes
4. What is American national symbol? A. bald eagle B. gray wolf C. bison D. elk
5. Which of following is true about the text?
A. Western White Pine forests cover 80% of the total forested areas of Yellowstone. B. Scientists at Oregon State University reintroduce wolves to change the grazing habits of local elk and attribute recent recovery of the aspen forest. C. Peregrine falcons nest on in large trees close to water.
D. The Yellowstone Park is comprised primarily of plain, forested, volcanic plateaus.
6. What caused the decline of peregrine populations before the 1970s? A. widespread use of pesticides B. poaching
C. illegal logging D. pollution
7. What’s the main idea for the text?
A. It announces people to protect the environment and wildlife. B. It introduces the development of Yellowstone’s tourism.
C. It talks about the animal living in the Yellowstone and their living conditions.
D. It makes a brief introduction to the geology of Yellowstone’ and the inhabit wildlife.
8. Petrified forests refer to the trees which _______________________________.
9. The best place to see grizzlies in Yellowstone is in _________________________.
10. Adult bald eagles are easily recognized by their ___________________________.
