Evolution and Behaviour

Abstract

Throughout this book we have stressed the adaptive nature of behaviour. Like morphological and physiological characteristics, behaviour has its origins in the animal’s genes. It is an evolutionary design feature, equipping the animal for survival and reproduction. It is the product of natural selection between alleles coding for different solutions to internal and external environmental problems. We have seen the shaping force of selection in several aspects of behaviour ranging from motivation and learning to migration, foraging, social behaviour and communication. During the discussion of different topics, a number of key concepts and principles have been mentioned: gene selection, kin selection, individual selection, group selection, evolutionary stable strategies, optimality theory, arms races and so on. In this chapter we shall examine some of these concepts in more detail. In some cases, for instance the various ‘levels’ of selection (gene,kin, group, etc.), there is still a good deal of confusion about exactly what concepts mean and how they should be used. Other ideas, like that of biological arms races, are of such ubiquitous importance that they merit further elaboration. It is important to be clear about the nature and application of these ideas if the current evolutionary approach to behaviour is to be understood. We begin, however, by discussing a phenomenon which really underlies all evolutionary changes but which has only been approached quantitatively, and with respect to behaviour, relatively recently, coevolution.