Abstract
This unique book is a creative contribution to the literature on speciation. Most chapters are written in German, with an English summary, and several key chapters are in English, with a German summary. The first section begins with a chapter by Scherer titled "Basic Types of Life." This chapter builds on the work of several researchers who have suggested that interspecific hybridization could be a useful taxonomic criterion. Frank Marsh (1941, Fundamental Biology) has suggested a taxonomic rank termed "basic type" or "baramin" which contains all individuals which are able to hybridize. Scherer further develops this concept, and suggests that the basic type is a systematic category, above the species level, that can be defined rather objectively. "Two organisms belong to the same basic type if (i) they are able to hybridize or (ii) they have hybridized with the same third organism." These two criteria are utilized in this and later chapters in an initial analysis of several plant and animal groups that seem to fit the definition of basic types.