The unified theory of evolution is an expansion of Darwinian theory that asserts that evolution is driven by entropic accumulation of genetic information that is constrained and organized primarily by the genealogical effects of phylogenetic history and developmental integration, and secondarily by ecological effects, or natural selection in its classical mode. Phylogenetic systematic analysis ...

In 1958 R. B. Clark and J. B. Cowey published a paper in which they presented a simple geometric model, based on the idea of a fibre-reinforced cylinder, to explain the mechanism underlying shape changes in ribbon worms and flatworms (Clark and Cowey, 1958). While their results may have been of interest to only a few biologists at that time, the essential idea of this paper, that a structure co...

Since the inclusion of molecular data in modern phylogenetic analyses, significant progress in resolving the origins and radiation of flatworms has been made, although some key problems remain. Here I review developments in the supply and use of systematic characters that provide the basis for diagnosis and phylogeny reconstruction, that in turn have driven systematic revisions and the interpre...

The structure of helminth communities in wild rodents is subject to seasonal variation, and is dependent on host age within years. Although between-year variation has been monitored, seldom has it been assessed rigorously by appropriate multifactorial analysis with potentially confounding factors taken into account. In this study we tested the null hypothesis that despite seasonal, host age and...