Coverage includes diversity and affinities of the flora, phusical environments and vegetation, landscape complexity and ecological diversity, population dynamics of annual plants, form and function of cacti, and the relationship between plants and the animals that use them as feeding and breeding resources. The text also examines the ecological consequences of modern agricultural development, as well as the impact on the modern biota of 40,000 years of change in climate, vegetation, megafauna, and ancient cultures.