• Desert shrubs return nutrients to the soil, ensuring the growth of future plants.Paul Edmondson/Photodisc/Getty Images
  
  Contrary to the common perception that desert climates are nearly bereft of life, the American desert regions are home to hundreds of species of mammals, shrubs, wildflowers, trees, insects, birds and reptiles. These species have adapted to thrive in extreme desert environments, and together form the various ecosystems of the deserts.
  
  

Desert Ironwood

• Desert Ironwood is native to the Sonoran Desert, which hugs the border between Arizona and Mexico. These trees can reach heights of up to 35 feet at maturity, with dark-gray bark that becomes deeply lined the older the tree gets. Its leaves are bluish-green, and its flowers bloom lavender to white in color, according to the Pima Community College Desert Ecology website. Wood from this tree is among the heaviest in the world -- so heavy that it sinks in water.
  
  

Silverleaf Nightshade

• Silverleaf nightshade is a perennial herb with blue, violet or white flowers that bloom from the spring months into the fall. According to the Washington State Noxious Weed Control Board, the silverleaf nightshade is well-adapted to arid climates and sandy soils, with its roots growing as far as 10 feet into the ground in search of water. The plant contains poisonous alkaloids that can harm livestock and humans. Silverleaf nightshade can be found in the dry country of Arizona and up through parts of the Pacific Northwest.
  
  

Black-Chinned Hummingbird

• The black-chinned hummingbird ranges from the desert country of Arizona and New Mexico into parts of California. According to the Living Desert website, these migratory birds feed primarily on nectar, but have adapted to eating spiders and insects. Males of the species have black faces with purple colored throats and light-green breasts. Females are predominantly green with white throats and breasts. Hummingbirds of this species only associate with one another for mating purposes and tend to live the single life otherwise.
  
  

The Chuckwalla

• The chuckwalla is a big, fat iguana native to the rocky lands of the Mojave and Sonaran deserts in the American southwest. Males have bodies colored in reddish-pink, orange, yellow or faint gray with black heads, shoulders and feet. Females tend to have bands of light and dark gray across the body with banded tails. The chuckwalla is a herbivore, and feeds mostly on flowers, fruit and leaves, according to Living Desert. The lizard obtains the majority of its water supply from the food it eats.
  
  

Black-Tailed Jackrabbit

• The black-tailed jackrabbit makes its home in desert country in the Southwest. The animal is distinguished by its extra long, black-tipped ears and hind legs. The black-tailed jackrabbit is nocturnal except in very cool daytime temperatures. The jackrabbit is highly specialized for desert life, and uses its rump and long ears to radiate heat upward and toward the ground. The animal's field of vision is nearly a full 360 degrees, which makes it tough for predators to sneak up on him. Even when they manage it, the black-tailed jackrabbit has a high escape velocity, with a top speed reaching 35-40 mph, even while zig-zagging.
  
  

Labyrinth Spider

• According to the Arizona-Sonora Desert Museum, the labyrinth spider is more recognized for its web than its actual physical form. The labyrinth spider loves constructing its orb-shaped web between the pads of the prickly pear cactus. The spider incorporates all debris, such as leaves and dead insects, into the web, while also constructing a small silken compartment below it where the spider waits for prey. The spider itself is relatively small, measuring about a quarter-inch long, with very thin legs and brown or gray body.