The author describes tropical rainforest ecology based around the 3 types of biological diversity (also known as biodiversity), which are known as genetic diversity, species diversity, and ecosystem diversity. While the book focuses on tropical rainforests, such ecosystems have micro-ecosystems and there are other ecosystems (cloud forests) found in the tropics. Species diversity is found among the world’s approximately 8.7 ± 1.3 million species. Species diversity also relates to the terms endemic species, threatened and endangered species, keystone or flagship species, indicator species, and charismatic species. Genetic diversity refers to the number of individuals within a given species. Because of the importance of biodiversity, the author concludes with a discussion of the landscape approach.