Adaptation concept is the logic cornerstone in the analytical model of evolution. Adaptation concept existed before Darwin's theory of evolution came into being. Adaptation is a ubiquitous phenomenon in the biosphere and a life-specific characteristic. Both evolutionists and non-evolutionists recognize the objective existence of biotic adaptation. Darwin's theory is a reductionistic analytic model for explaining the general process of biotic adaptation. Therefore, by comparison, the concept of adaptation is much more ingrained than others such as evolution and variation in evolutionism.
However, interpretation of the adaptation process was not successful. Both evolutionism and the Modern Synthesis failed to fulfill this goal in biology. Why did evolutionism and the follow-up works still fail to close the fault zone between contemporary functional biology and evolutionary biology?
The fault zone between functional biology and evolutionary biology reflects that the detailed evidences of (in a broad sense) physiological functions in functional biology can only be used to prove the related evolutionary variations among species in response to the global environmental changes through comparative study. In other words, what the evidence has revealed is the interspecific adaptive variation. But these detailed evidences of (in a broad sense) physiological functions in functional biology cannot be amply incorporated into an analytic framework for explaining the individual adaptive variation within species. If we analyzed a given species' adaptive variation in detail and wanted to reach the physiological level, we would face an insurmountable difficulty to establish a reference frame. As this has moved away from the interspecific comparative system, it is a question about intraspecific comparison. The connotation meaning structure theory should focus on this issue.
The concept of adaptation is a bridge scaffold in evolutionism, and the real bridge has not yet been built. The biotic adaptation theory is only a rough, theoretical framework, and a mature adaptation theory has not been formed. Mayr's Gap manifested itself at this point, reflecting the basic contradictions in modern biological science. This creates a dilemma. Evolutionism was originally generated for solving the basic contradictions, but it became a part of the basic contradictions. This is the fundamental reason why contemporary evolutionism is in a dilemma: evolutionism was generated for the completion of this historic synthesis, but actually failed to achieve its goal. There was a lot of finger pointing in response to this failure.
The modern synthesis is also of reductionistic mode and in the direction of adaptationism, but it failed to close the fault zone too. The problem is its skipped-over-middle-layer interpretation. The Modern Synthesis aims at explaining questions on the second level of the adaptation theory, but it directly uses gene variation to explain variations in phenotype, and this pseudo reductionistic theory conceals the position of the second level adaptation theory. The Modern Synthesis is so authoritative that a real second level adaptation theory is missing. The requirement to build a second level adaptation theory has not been taken seriously for a long time, for people used the modern synthesis thinking to replace it.
The Modern Synthesis has a special historic status in the history of biology. Although it failed, it was a glorious failure. Historically, the Modern Synthesis is the first attempt to integrate microbiological knowledge on the basis of Darwinian reductionistic mode, and it is also the first relatively successful case to associate traditions of functional biology with traditions of adaptationistic biology. DNA pattern enables functional biology to explain phenotypic variation, so the functional biology willingly accepts adaptationism and evolutionism after the forming of the syncretic mode. This synthesis has greatly boosted the mutual understanding and absorption of the two traditional biological disciplines. Since the coming of the Modern Synthesis, the seminal seed of physiological Darwinismí¬neo-adaptationismí¬has been sown. Although the the modern synthesis is no longer in force, neo-adaptationism grows. In this sense, the Modern Synthesis has rendered outstanding service. This is the historic role of the Modern Synthesis.
Neo-adaptationism has actually moved away from the reductionistic analytic ways of the original evolution theory, the first transverse (transdisciplinary) synthesis, and broken away from the Modern Synthesis , the second transverse synthesis, representing a new developmental trend which may be a third transverse synthesis. This tendency could be verified when we compare their disparities in the definition of adaptation. That is to say: evolutionism and the Modern Synthesis, in nature, explain the adaptational mechanisms of biosphere, and neo-adaptationism aims at explaining the physiological adaptation of individual organisms. Considering the latter's research area, neo-adaptationism practically involves the focusing issue of the meaning structure theory.
In brief, meaning systems theory, in the sense of reductionism, should include two reductive levels:
The first level of the reductive explanation is about how individuals contribute to the biosphere.
The second level of the reductive explanation is on how the microcosmic change contributes to an individual.
In this way, the skipped-over-middle-layer interpretation will not appear.
Evolutionism and the Modern Synthesis have established a mature first level of the reductionistic model of the connotation meaning systems theory, and the second level of the model is still an open void. That is to say, after its establishment, evolutionism has failed to solve completely the reductionistic theoretical issues about adaptation, and it has only settled the first part of it. There are essentially two levels of adaptation theory, while evolutionary theory is the first level of the connotation meaning systems theory. The general theory of biological paradigm lacks the second tier of the connotation meaning systems theory, which is a deep-structure theory about physiological adaptation solutions.
This is the deep-rooted cause for why Mayr's Gap cannot be bridged.
Connotation meaning structure theory is facing a historic mission to create a set of new concepts and theoretical systems that can be used to build a reductionistic model of the second level adaptation theory, which at the same time can fuse the two level's reductionistic models of adaptation theory into a unified setting. Building a reductionistic model of the second level adaptation theory is the core issue of deep-structure study.