The following sections of this BookRags Literature Study Guide is offprint from Gale's For Students Series: Presenting Analysis, Context, and Criticism on Commonly Studied Works: Introduction, Author Biography, Plot Summary, Characters, Themes, Style, Historical Context, Critical Overview, Criticism and Critical Essays, Media Adaptations, Topics for Further Study, Compare & Contrast, What Do I Read Next?, For Further Study, and Sources.
(c)1998-2002; (c)2002 by Gale. Gale is an imprint of The Gale Group, Inc., a division of Thomson Learning, Inc. Gale and Design and Thomson Learning are trademarks used herein under license.
The following sections, if they exist, are offprint from Beacham's Encyclopedia of Popular Fiction: "Social Concerns", "Thematic Overview", "Techniques", "Literary Precedents", "Key Questions", "Related Titles", "Adaptations", "Related Web Sites". (c)1994-2005, by Walton Beacham.
The following sections, if they exist, are offprint from Beacham's Guide to Literature for Young Adults: "About the Author", "Overview", "Setting", "Literary Qualities", "Social Sensitivity", "Topics for Discussion", "Ideas for Reports and Papers". (c)1994-2005, by Walton Beacham.
All other sections in this Literature Study Guide are owned and copyrighted by BookRags, Inc.
Polyphylogeny is a term used in the science of systematics. It describes a group of species that are classified in the same taxon, but do not share a single ancestor. Systematics is the study of biological diversity looked at through an evolutionary perspective. It was an outgrowth of taxonomy and has slowly become more sophisticated since the time Charles Darwin posed the evolutionary theory. Scientists who pursue this subject attempt to group organisms based on probable evolutionary relationships. They create genealogy diagrams, called phylogenic trees, that graphically show these relationships. A polyphylogenic group would contain species that seem related, but have different evolutionary ancestors. These species are grouped using a variety of characteristics such as fossil records, comparative anatomy and DNA and protein analysis. While most phylogenic trees contain polyphylogenic groups, the ideal in systematics is for each group to have a common ancestor or be monophylogenic. Unfortunately, a large amount of conflicting data is often collected. For example, two unrelated organisms may be grouped together because they independently evolved similar traits. Incidents of this type of convergent evolution create errors in phylogenic trees. However, as more data is collected about various species, scientists hope to achieve the goal of a unified phylogenic tree.