Functional morphology and evolutionary biology

Abstract

In this study the relationship between functional morpholoy and evolutionary biology is analysed by confronting the main concepts in both disciplines. Rather than only discussing this connection theoretically, the analysis is carried out by introducing important practical and experimental studies, which use aspects from both disciplines. The mentioned investigations are methodologically analysed and the consequences for extensions of the relationship are worked out. It can be shown that both disciplines have a large domain of their own and also share a large common ground. Many disagreements among evolutionary biologists can be reduced to differences in general philosophy (idealism vs. realism), selection of phenomenona (structure vs. function), definition of concepts (natural selection) and the position of the concept theory as an explaining factor (neutralists vs selectionist, random variation, determinate selection, etc.). The significance of functional morphology for evolutionary biology, and vice versa depends on these differences. For a neo-Darwinian evolutionary theory, contributions from functional and ecological morphology are indispensable. Of ultimate importance are the notions of internal selection and constraints in the constructions determining further development. In this context the concepts of random variation and natural selection need more detailed definition. The study ends with a recommendation for future research founded in a system-theoretical or structuralistic conception.

System-theoretical (Holistic) Approach to the Modelling of Structural–Functional Relationships of Biomolecules and Their Evolution: an Example of Triterpene Glycosides from Sea Cucumbers (Echinodermata, Holothurioidea)

“…Indeed, the elimination or change of any elements of the high integrative functional system would act upon the maintenance of the whole system as Frazzeta (1975) noted. The importance of a general structural plan of such molecules for maintaining conformity to a target or receptor is very similar to the importance of the general form of a morphofunctional system (for example, the form of the head of gulls is very important for gulping "sh (Dullemeijer, 1980). The situation in evolution of sea-cucumber glycoside is almost the same: the general structural plan of these substances is very conservative in di!erent taxa of holothurians.…”

“…Such an isolation is always a little arbitrary but the design of a network diagram is useful for demonstrating a very complicated picture of structural}functional relations. An TRITERPENE GLYCOSIDES FROM SEA CUCUMBERS example of such a diagram is the scheme of morphological}functional relationships of the heads of snakes (Dullemeijer, 1974(Dullemeijer, , 1980.…”

“…Moreover, it is possible to realize more than one organogenesis mode during an evolutionary transformation of any structure. A more accurate method is the system-theoretical or holistic approach for modeling of structure}functional relationships of complicated morpho-functional adaptive complexes developed by Van Der Klaauw (1945) and Dullemeijer (1974Dullemeijer ( , 1980. Van Der Klaauw (1945) proposed subdivision of morphological}functional complexes of living organisms into functional components.…”

Functional homology and homology of function: biological concepts and philosophical consequences

“…xii Analyses of these interdependencies among functional elements are situated in methodological approaches from disciplines like functional morphology (Dullemeijer 1981;Schwenk 2001). For example, Lauder (1994) investigated jaw muscle activity patterns as homologues of function in fishes.…”

“…The relationship between form and function is asymmetric in that structures have an epistemological priority in the decomposition and investigation of biological activities (Dullemeijer 1981). This is especially salient in the historical record treated by paleontology where skeletal structures are more prevalent and the univocal determination of functions in extinct animals is difficult (Lauder 1995).…”