`Evolution' in Perspective

Introduction This work sets out to review the nature of classical natural evolution, and to see if we, in the field of software development, can reflect on these concepts to assist in developing evolvable software systems. 2. Biological Evolution Evolution theory is the unifying theory of biology. It seeks to explain the continuous natural development of organic systems. It provides the basis of our understanding of how the functions of biological entities at all levels (population, organisms, genes) are the product of a non-random factor operating in conjunction with random factors within a framework of historical constraint It provides an answer when biologists ask `How did we get here', but not `Why'. Before Darwin, evolution was thought of as the `unfolding of immanent potentialities within existing species', i.e. the manifestation of essences which lay dormant in earlier species. People were aware of the changes taking place in organisms over time, but