Desert Characterization • A Desert is a region on Earth which receives less that 10in of annual rain fall, and is generally taken over by high temperatures. • Deserts cover one fifth of all of Earth’s surfaces
Temperature • Annual temperature ranges from 20-25º. • Many deserts receive little rainfall. • The heaviest rainfall occurs most frequently in April or May.
Formation of a Desert • Many deserts have been formed by the flow of air masses over the planet. • As the earth turns on it’s axis, it makes huge air swirls causing the hot air to rise over the equator and flow north and southward. • This in turn sucks up moisture while warming the land which causes it to become dry.
Desert Soil • Caliche is a reddish-brown to white layer of soil found in many desert solids. • This type of soil is formed by plants releasing water and carbon dioxide from their. • Soils that form in arid climites mineral soils and have low organic contents.
Water Channels • In the desert, underground channels carry water from mountains that are most of the time near by into the desert. • If the channels were not covered by the soil it the water would evaporate. • Moisture in the desert can come from sources such as rain, sweat, dew, pools, lakes, sap, and breath, these evaporate quickly in the hot air.
Winds • A desert wind can vary from a warm breeze to a sand storm. • Wind sometimes even sandblasts rocks which will then build sand dunes which can become 200 meters high
Animals • Animals in the desert must survive in a hostile environment. Intense heat, searing sun, and lack of water are just a few of the challenges facing desert animals. • Animals that live in the desert have many adaptations. • Some animals adapt by spending most of the day underground and out of the hot sun. • Some animals rarely spend any time above ground.
Plant an Animal Species • Only second to the Rainforest, the Desert has the most variety of plant and animal species. • Though many desert plants look different than plants in other Biomes.
Addax • The color of the addax varies widely between individuals, but there is always a mat of dark-brown hair on the forehead, and both sexes have thin, spiral horns. • The addax has adapted to walking on soft sand, and they never drink, obtaining all the moisture they need from their food, which includes succulents.
Cactus Wren • . Cactus wrens are found in areas with thorny shrubs, cacti and trees and forage mostly on the ground around vegetation for insects, such as beetles, ants, wasps and grasshoppers, and occasionally lizards or small frogs.
Desert Night Lizard • The desert night lizard varies in coloration over its range but is marked with many small dark spots. • Night lizards give birth to live young. • It frequents yucca plants and agaves and feeds on termites, ants, beetles and flies, which it finds among vegetation or rocks.
Blind Western Snake • It lives almost anywhere where there is sandy or gravelly soil suitable for burrowing and spends much of its life below ground, occasionally emerging at dusk on warm evenings or on overcast days. • It feeds on ants and termites, which it locates by smell, and with its slender body, it can enter right into their nests.
Thorny Devil • Its body is covered with bristles with large, conical spines, and it has spines above each eye and a spiny hump behind its head. • It is a slow-moving creature, which forages for its food, mainly ants and termites, on the ground.
Vulture • Its powerful hooked bill cuts easily into carrion, and its bare head and neck save lengthy feather-cleaning after plunging deep into a messy carcass. • The immense broad wings, with widely spaced primary feathers, are ideal for soaring and gliding for long periods.
SaguaroCactus • The green stem of the Saguaro Cactus stores all of its water. • Photosynthesis occurs in the top layer of the stem instead of in leaves. Under ground this cactus has another adaptation that is hidden from us, its roots. • Theses roots extend far away from its trunk. The roots collect water after rain and is then Stored in the stem,the water keeps the saguaro alive until the next rainfall.
Fish Hook Cactus • The fish hook shaped spines of the Fish Hook Cactus help divert heat and shade the growing tip of the plant. • Many barrels lean further toward the sun as they grow. Some may eventually uproot themselves.
Barrel Cactus • The pleated shape of the Barrel Cactus allows it to expand when it rains and store water in its spongy tissue. • It shrinks in size during dry times as it uses the stored water.
Just a little Quiz • In what months does the heaviest rainfall occur? • What has more of a variety of plants than the desert? • Which animal is the one covered in bristles and spines?
Quiz Answers • April or May. • The Rainforest. • Thorny Devil.