The desert biome is an ecosystem that forms due to the low level of rainfall it receives each year. Deserts cover about 20% of the Earth.There are four major types of desert in this biome-hot and dry, semiarid, coastal, and cold.They are all able to inhabit plant and animal life that are able to survive there.he desert biome is an ecosystem that forms due to the low level of rainfall it receives each year. Deserts cover about 20% of the Earth.