Darwin's observations and an idea that revolutionized scientific thought. Darwin's Revolutionary Idea 20. Chapter 17 - Populations, not individuals, evolve. Natural selection is a driving force for evolution and genetic variation provides the raw material. The evolution of behavior.
Energy flow through the environment.
Chapter 28 - We are rapidly approaching the ability of the Earth to support the human population. Physiological systems maintain a dynamic equilibrium. Anatomy and function of neurons and the effect of drugs on nerve function 31. Chapter 26 - Organization of the vertebrate nervous system and its role in internal and external monitoring, information processing and initiating responses. Along with the nervous system, hormones help coordinate body functions.