Download or read book The Great Paleozoic Crisis written by Douglas H. Erwin and published by Columbia University Press. This book was released on 1993 with total page 342 pages. Available in PDF, EPUB and Kindle. Book excerpt: The culmination of more than fifty years of research by the foremost living expert on plant classification, Diversity and Classification of Flowering Plants is an important contribution to the field of plant taxonomy. In the last decade, the system of classifying plants has been thoroughly revised. Instead of describing every individual family, Takhtajan includes descriptions in keys to families, which he calls "descriptive keys." The advantage of descriptive keys is that they give both the characteristic features of the families and their differences. The delimitation of families and orders drastically differs from the one accepted by the Englerian school and from the one accepted in Arthur Cronquist's system. Takhtajan favors the smaller, more natural families and orders, which are more coherent and better-defined, where characters are easily grasped, and which are more suitable for information retrieval and phylogenetic studies, including cladistic analysis (because it reduces polymorphic codings).