Deserts experience daily fluctuations in temperature. Day temperature can reach as high as 54°C while temperature may drop to near freezing point during night time. Rainfall is spare and evaporation is rapid. These conditions best characterize a desert. Organisms experience the most drastic change in hot days and cold nights with high as a result of the absence of water vapor in the air. Plants should be resistant enough to survive. It is a requirement that they should be able to obtain and conserve water. Desert plants have reduced leaf surface area, an adaption to reduce the rate of evaporation. The presence of small hair on the leaf surface enhances their ability to temporarily conserve a large amount of water.
The species of these plants are divided into two groups: those which are distributed along the areas where winters are cold ( Sagebrush ), and those located in areas where winters are warm ( Creosote bush and Cacti ). On the other hand, small plants grow, flower, and produce quickly in one season.
They are called "Annuals". The second requirement is that they should be able to adapt to extreme heat and cold weather. Animals have developed a lifestyle where they can hide from the intense heat of the sun. Many are nocturnal. Nocturnal animals are those that are active at night. Some content themselves with burrowing under the ground, like the Kangaroo rat, to hide from the heat of the sun.
The driest deserts have no perennial vegetation. However, shrubs are scattered, interspersed with cacti species, all over a less arid desert community until rainfall triggers their germination. Plants bloom annually when rains fall.
Desert animals like birds, ants, and some rodents that eat seeds are hunted by lizards, snakes, and hawks.