selection and natural selection in bird speciation'', disputes the generality of this conclusion by showing that female preferences evolve deterministically to a single point, rather than to divergent points as would be required for speciation. Nevertheless, song, plumage, and courtship display could lead to restricted patterns of female choice and hence to reproductive isolation. Female birds exhibit preference for complex songs, which may be multiply configured, as can plumage patterns.
The multiplicity of closely related fish species in the great African lakes is astounding. There are more than 600 cichlid species in Lake Malawi, 250Β±500 in Lake Victoria, and more than 170 in Lake Tanganyika. In each of these, most species diverged from one single species within the last few tens of thousands of years. This occurred without any physical isolation in Lake Malawi or Lake Victoria, although Lake Tanganyika has subdivided into two or three isolated lakes during times of low water level. George F. Turner (``Explosive speciation of African cichlid fishes'') evaluates the relative contributions of various modes of speciation: extralacustrine (which he largely excludes), allopatric (within lakes), and sympatric speciation. The leading process, as he sees it, is population subdivision according to habitat preferences, coupled with sexual selection that diversifies male courtship traits.
J. John Sepkosky (who regretfully passed away recently, while still in his prime) uses his unsurpassed statistical knowledge of the diversity of the fossil record to infer that rates of speciation have vary greatly both over geological time and across biological groups (Rates of speciation in the fossil record''). A surprising conclusion here is that rates of speciation have, on the whole, decreased from the Cambrian to the present. S. Conway Morris (The evolution of diversity in ancient ecosystems: a review'') points out the extreme longevity of prokaryotes and unicellular eukaryotes which were the only organisms on Earth for at least two-thirds of life's history. He also details the limited knowledge of the causes of the dramatic increases in diversity of the fossil record that occurred during, for example, the Cambrian ``explosion.''
Other chapters in Evolution of Biological Diversity are scholarly and of interest, with little that is fuzzy or irrelevant.
Evolution of Biological Diversity comes on the tail of another collection on the same subject, also published by Oxford University Press: Endless Forms. Species and Speciation, 1998 (Daniel J. Howard and Stewart H. Berlocher, Eds.). This book is dedicated to Guy L. Bush, who, in his chapter, tells his arduous scientific saga promoting, with evidence from Rhagoletis fruit flies, sympatric speciation as a common, if not general process. Although this earlier volume is longer, with more detail and diversity of viewpoints on key themes such as the mechanisms of reproductive isolation, the genetics of speciation, and the