This question is very difficult to prove, but theories have been postulated which attempt to explain why evolvability is a selectable trait. The difficulty surrounding selection and evolvability is that evolvability is a trait of lineages as opposed to individuals and this is where the difficulty regarding selection comes in.
The ability of viral and bacterial pathogens to develop antibiotic resistance is a combination of natural selection and evolvability. The application of antibiotics to bacterial populations places them under a stressful environment. Bacteria and viruses are prokaryotes and therefore a lot of their genetic material is composed of RNA. RNA is genomically unstable and has a much higher mutation rate than DNA.
During the early 1990’s scientists were more concerned about the actual resultant variation from Darwinian evolution, rather than its origin. Many scientists assumed that the origin of the variation was a product of Darwinian evolution. But recent evidence from simulations and observations of simple evolutionary systems has yielded results which prove that this is not the case (Nehaniv, 2003).
Kimura (1983) is one of the key players of research into genetic neutrality and had a major role in its rise to prominence. Kimura referred to neutrality as genetic variation that does not result in change to the fitness of an organism. Moreover any change has to remain neutral in any environmental, genetic or physical condition.
Robust biological systems acquire less phenotypic variation through environmental stressors or genetic damage as compared to less robust systems (Wagner, 2005). The ability of organisms to balance robustness and evolvability is the key for surviving a billion generations of varying environmental conditions with high levels of consistency (Lenski et al, 2006).
Evolvability is recognised as the ability of an organism of any particular lineage to develop heritable phenotypic variation (Kirschner, 1998). Darwin’s theory of evolution is fundamental to Evolvability, as it is evolution which allows for the development of this heritable phenotypic variation. This variation could stem from natural selection or it could be from the result of acquired genetic change functions which can lead to novel functions.
