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.
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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.
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Divergent evolution is also known as divergence. This is the opposite of convergent evolution.
Starting from a point at which there is one basic form of organism, then when different selective pressures are placed on that one organism type, that one form can produce a wide variety of new types. If only one structure on the organism is considered, these changes can either add to the original function of the structure or they can change it completely. Divergent evolution is one of the first steps in speciation, the production of a new species. Divergence can be seen when looking at any group of related organisms; the differences are produced from the different selective pressures under which the life forms live. Any genus of plants or animals can show divergent evolution, for example, the diversity of floral types in the orchids. The greater the number of differences present, the greater the divergence. Scientists speculate that the greater the divergence, the greater the length of time since the organisms in question shared a common ancestor.
Divergent evolution can occur quite easily in nature. If a freely interbreeding population on an island is separated by the appearance of a barrier to breeding, such as the presence of a new river, then, over time, the organisms may start to diverge and show differences. If the opposite ends of the island have different pressures acting upon them this pressure will produce divergent evolution. When the organisms were capable of freely interbreeding the differences caused by the different ends of the island would be averaged out over the whole population and not be discernible.