Charles Darwin's (1859) theory of evolution used a synergetic or co-evolutionary model of fitness that characterised it in respect of an organism's 'organic and inorganic conditions of life'. When a cock-bird attracted a mate or a long-tongued insect found deep-throated flowers to pollinate, they activated dynamic multipliers that selectively rewarded success and opened new possibility spaces of future opportunities and challenges. If the co-evolution of deep-throated flowers and long-tongued moths led to an exaggeration of these traits, then conventional pollinators might be locked out and long-tongued pollinators would thrive.
During the first half of the 20th century, however, biologists re-defined evolution as a change in the gene-pool driven by natural selection (as described by Fisher 1930). This gene-centred model is often referred to as the 'modern synthesis' (Huxley 1942). Its success was due, in part, to experimental evidence that falsified the continuity assumptions Darwin had built into his theory and, in part, to the physicist Erwin Schrödinger (1944), who saw analogies between genetics and quantum theory and argued for the existence of a genetic blueprint. Watson and Crick's (1953) work on DNA seemed consistent with Schrödinger's blueprint hypothesis and the Darwinian model was set aside. In the modern synthesis, natural selection becomes a filter that punishes failure, and fitness is an attribute of a gene. The result is a heroic model (Landau 1991) in which genes either have what it takes to survive or are eliminated.
Darwin's enthusiasm for Herbert Spencer's phrase 'survival of the fittest' (see, for example, Chapter 4 of the sixth edition of Origin; Darwin 1871a) suggests that he too found heroic models attractive. Darwin often assumed that the 'conditions of life' experienced in a region would be more or less uniform. Under the assumption of uniformity one can reasonably speak of some organisms being heroically fitter than others. The differences between Darwin's theory and the modern synthesis become significant, however, when one tries to connect the two models to later developments in systems ecology. With Darwin's theory it is possible to treat fitness as the upshot of co-evolutionary processes that reward success, because selection operates on organisms in a populated neighbourhood, where co-operative behaviour can greatly enhance survival prospects. With the modern synthesis, however, there is only the heroic model. Selection does not reward success; it punishes failure. The heroes that survive are not organisms but genes. Ecological synergies are hard to model if natural selection operates on gene pools and there are no selective multipliers to reward co-operative strategies.