An adaptation, or adaptive trait, is any heritable trait, that enables organisms to survive through natural selection and reproduce better under prevailing environmental conditions. Natural selection tends to preserve beautiful adaptation in populations and discard harmful ones. The evolution of animal form and function is the conceptual backbone of this book. It not only provides the framework for Animal Diversity, but also shifts the paradigm from a chiefly descriptive discipline to a dynamic predictive science. It is a book narrating rambling series of stories or vignettes about randomly selected animals or model organisms and their unique way of life. Animals might not be able to speak or master advanced language techniques, but they certainly have other ways of communications. Species often rely on verbal and nonverbal forms of communication, such as calls, nonvocal auditory outbursts, like the slap of a dolphin's tail on the water; bioluminescence; scent marking; chemical or tactile cues; visual signals and postural gestures. When it comes to acoustic communication, not every member of a species is just alike. Animals in different regions have often been overheard sounding off in different dialects. Communication between species can play important roles as well. One study suggested that the reason Madagascan spiny-tailed Iguana have well-developed ears, despite the fact that they don't communicate vocally is so that they can hear the warning calls of the Madagascan paradise flycatcher. The book is weaved intricately around these bizarre adaptations.