9781422277515

desert nights can be bitterly cold. Very cold regions of the Arctic and the Antarctic are called polar deserts. They are extremely dry through- out the year because all their moisture is locked up in ice. There are often semi-arid regions fringing the arid deserts, where precipitation ranges between 10 and 35 inches (25 and 90 cm) each year. These are the areas where unsuitable farming methods and native plant destruction are most likely to turn the land to desert. Different Types of Desert All deserts are arid, but they are arid for different reasons. There are four main processes that create deserts and keep them that way, and so there are four types of desert. They are horse-latitude deserts, con- tinental deserts, rain-shadow deserts, and coastal deserts. A biome is a very large ecological area, with plants and animals that are adapted to the environmental conditions there. Biomes are usually defined by physical characteristics—such as climate, geology, or vegetation—rather than by the animals that live there. For example, deserts, rainforests, and grasslands are all examples of biomes. Plants and animals within the biome have all evolved special adaptations that make it possible for them to live in that area. A biome is not quite the same as an ecosystem, although they function in a similar way. An ecosystem is formed by the interaction of living organ- isms within their environment. Many different ecosystems can be found within a single biome. Components of most ecosystems include water, air, sunlight, soil, plants, microorganisms, insects, and animals. Ecosystems exist on land and in water, with sizes ranging from a small puddle to an enormous swath of desert. Biome versus Ecosystem

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Deserts