Introduction

The problem tackled in this book relates to the fact that the outcome of phylogenetic analyses relies upon the constituent parts of a data-matrix. These issues arc concerned with character analysis, which Pogue and Mickevich (1990) have referred to as the bête noire of systematics. In the first chapter of this volume, Andrew Brower poses the central questions of character analysis: what is a character, and how do we delimit characters, character states, and the relationships between them? Brower emphasizes that this question of character analysis precedes tree-building (by whatever algorithm is used) and thus determines the outcome of a systematic analysis. Despite this importance, much of the literature debating systematic theory over the past three decades has discussed tree-building rather than character analysis. Brower reviews the development of ideas of systematics and homology from pre-Darwinian times to the present, thus placing into context cladistic parsimony (e.g. Farris, 1970, 1983), the tree-building method preferred by the authors in this book.