Evolution, development and learning all affect the organisation of nervous systems and all are inextricably linked together. The importance of evolution can be observed easily simply by looking at the differences that occur in nature, from the relatively simple systems in invertebrates through to what is perhaps the pinnacle of complexity in the primates. Natural selection will act upon the behaviours asserted by the animals and the underlying neural circuitry will be selected as a consequence. New structures that arise as a result of such selection will be present in some animals as opposed to others as developmental systems will have been affected due to the appearance of novel homeobox genes. As a result, individuals of phyla will have similar basic neural organisations, differing only due to polymorphism which also provides the raw material for natural selection. …
