Predation Pressure and Evolution in Lake Nyasa

IN papers dealing with the evolution of fishes in the Great Lakes of East and Central Africa, Worthington 1–3 postulates that a major contributory factor to the great adaptive radiation shown by the family Cichlidae in certain lakes, notably Victoria, Edward and Nyasa, has been the absence from their waters of active predators. The theoretical implications of this suggestion have been accepted by Huxley 4 but have been criticized by Mayr 5 .