Desert

Desert

• a land of extreme heat and dryness; sudden flash floods and cold nights
• a harsh environment, often named 'Death valley', 'the place of no return'
• very, very dry
  (even wettest deserts get less than 10 inches of precipitation per year)
• only a few periods of rains per year with lots of time between them
• during the day, temperature are as high as 100F ; but during the night, tempereature can fall till 40s and 50s.
  (Because deserts have only 10% to 20%  humidity to trap temperatures and have so little trees and other vegetation to cool down heat, the cool down rapidly when sun sets and heat up quickly after sun rises)

Types

• Hot (main form of precipitation: rain)
  - includes: Thar, Sahara, Monte, Kalahari
• Cold (main form of precipitation: snow or fog)
  - includes Namib, Iranian, Great Basin, Gobi

Location

• many are found in bends along 30degrees latitude north and 30degrees latitude south.
• some located by mountains are are caused by the 'rainshadow' effect.
  - As air moves up over a mountain range, it gets cold and loses its ability to hold moisture - so its rains or snow. When ari moves over to the other side of the mountain, it gets warmer. Warm air can hold lots of moisture, so it doesn't rain as much and a desert is formed.

Deserts of the world

World's Largest Deserts
Desert	Location	Square Miles	Square Kilometers
Sahara	North Africa	3,500,000	9,065,000
Gobi	Mongolia-China	500,000	1,295,000
Kalahari	Southern Africa	225,000	582,000
Great Victoria	Australia	150,000	338,500
Great Sandy	Australia	150,000	338,50



Deserts of North America
Name Location	Size	Physical Features	Some Plants & Animals	Special Facts
Chihuahuan North Central Mexico and Southwestern United States (Arizona, New Mexico, Texas)	175,000 mi2 455,000 km2	High plateau covered by stony areas and sandy soil. Many mountains and mesas.	cacti, chihuahuan flax, creosote bush, lechuguilla, mesquite, mexican gold poppy coyote, diamondback rattlesnake, javelina, kangaroo rat, roadrunner	Largest North American desert. Big Bend National Park located here; more species of birds seen in Big Bend than in any other National Park in the U.S.
Great Basin Western United States (Idaho, Nevada, Oregon, and Utah)	158,000 mi2 411,000 km2	Covered by sand, gravel, and clay. Many moutains ranges, basins, and large expanses of salt flats.	greasewood, sagebrush, shadscale bighorn sheep, jackrabbit, pocket mouse, poor-will, pronghorn antelope, sage thrasher, side-blotched lizard	Great Salt Lake located here.
Mojave Southwestern United States (Arizona, California, Nevada)	25,000 mi2 65,000 km2	Covered by sandy soil, gravelly pavement, and salt flats.	creosote bush, desert sand verbena, joshua tree, mesquite bighorn sheep, chuckwalla, coyote, jackrabbit, sidewinder, zebra-tailed lizard	Death Valley located in this desert.
Sonoran Southwestern United States (Arizona, California) and parts of Mexico (Baja Peninsula, Sonora)	120,000 mi2 312,000 km2	Covered by sand, soil, and gravelly pavement. Gets more rain than any other North American desert.	agave, coulter's globemallow, creosote bush, desert mariposa lily, mesquite, ocotillo, paloverde, saguaro coati, elf owl, gila monster, kangaroo rat, pack rat, roadrunner, sidewinder, tarantula	Most complex animal-plant community of any desert.

Desert Plants

• home to many living things
• second only to tropical rainforests in the variety of plant and animal species that live there
• main adaptions to survive in the harsh conditions are ability to collect and store water and features that reduce water loss
• Includes old man cactus, prickly pear cactus, dragon tree,



Desert animals

• must adapt to the harsh conditions to survive; some never drink but gets their water from seeds and plant,  some sleep during the hot day and only comes out at night to eat and hunt, some rarely spend time above ground
• Includes addax, dingo, fat sand rat, fennec fox