ABSTRACT
The main subject of this chapter is the animal portion of what biologists call the tree of life (see Section 2.2.4). It provides a summary overview, tailored to the context of this volume, of the who, what, when, where, and how of the processes and results of organic evolution in animals. The possible why(s) of evolution we leave for others elsewhere. Recent overviews of modern evolutionary biology include Levinton (2001), Hedges and Kumar (2009), Ruse and Travis (2009), Bell et al. (2010), Roff (2010), Koonin (2011), Shapiro (2012), Avise and Ayala (2013), Dial et al. (2015), and Eldredge (2015).
