Deserts are composed of plants and animals living together in what seems like an oppressive environment. Living and nonliving elements interact complexly, forming the desert ecosystem. The lifeblood, of course, is the sun's energy, converted to a living form by green plants. Unlike most ecosystems, in which plants complete for space in the sun, the desert's sparsity is created in part by too much solar energy. Plants use one of two life strategies to survive.
Annuals avoid the extremes, compress their life cycle, and exist while the environment is favorable.
Sudden carpets of spring wildflowers are displays of awakened dormancy as seeds, like time travelers, revive to spout flower, and renew their kind. The alternate strategy is that of the patient perennial. Conservative year-round residents like the Joshua tree flourish during the moist periods and bide their time during long droughts. Many animals derive their energy from plants, but desert plants give up the fruits of their production only reluctantly. The kangaroo rat avoids these obstacles by eating seeds.