Showing papers by "John A. Endler published in 1988"

Frequency-dependent predation, crypsis and aposematic coloration.

Abstract: Frequency-dependent predation may maintain or prevent colour pattern polymorphisms in prey, and can be caused by a variety of biological phenomena, including perceptual processes (search images), optimal foraging and learning. Most species are preyed upon by more than one predator species, which are likely to differ in foraging styles, perceptual and learning abilities. Depending upon the interaction between predator vision, background and colour pattern parameters, certain morphs may be actively maintained in some conditions and not in others, even with the same predators. More than one kind of predator will also affect stability, and only slight changes in conditions can cause a transition between polymorphism and monomorphism. Frequency-dependent selection is not a panacea for the explanation of variation in animal colour patterns, although it may be important in some systems.

The Processes of Evolution: Toward a Newer Synthesis

Abstract: Evolution consists of an aggregate of processes of various kinds which affect different taxa differently. Major processes are tentatively classified as mutational, constraining, frequency-changing, adaptive, rate-determining and direction-determining. Each is examined, with major gaps in knowledge identified. -P.J.Jarvis