Riedl, Rupert - Order In Living Organisms

The Structure of Concern Project compares many theoretical models from many disciplines to the Adizes PAEI model, arguing that they must all be reflecting the same underlying phenomenon. One concern structure model is described below.

Rupert Riedl was an Austrian zoologist who made many contributions to the field of evolutionary biology, ecology, and morphology[1]. At a time when evolutionary theory emphasized
population genetics to the exclusion of almost all else, Riedl began examining the role of what might be called ‘developmental systematics’ in evolution. This approach “…emphasizes the role of
functional and developmental integration in limiting and enabling adaptive evolution by natural selection. The main objective of this theory is to account for the observed patterns of morphological evolution, such as the conservation of body plans…” [2].

Riedl did not try to demote natural selection as a pre-eminent cause of evolution, but he did seek to promote the importance of developmental factors as primary delimiters and enablers of evolutionary change, particularly in the domain of animal morphology.

Riedl’s 1978 book entitled Order in living organisms: A systems analysis of evolution presents an account of animal morphology as an evolvable system, and the core concepts of this work fall into a concern structure pattern, primarily due to their hierarchical structure. Riedl understands a morphological system to consist of four distinct ordering principles, given in PAEI order below:

P – Standard Part
A – Interaction
E – Hierarchy
I – Traditive Inheritance

P - Standard Part: The constraint that any larger form in the universe must be composed of multiple “copies” or instances of specific sub-forms or components. If we transfer this insight and apply it to the hierarchical structure of tasks and events, these would be the concrete particular objects that P managers prefer to concern themselves with.

A – Interaction: Constraints resulting from the assembly of these standard parts into a system. Thus the degrees of freedom or variability of standard parts are limited to the subset that is compatible with other standard parts with which it interacts as part of a larger ensemble. These are same-level constraints are imposed by system participation, through mutual dependencies and determinative decision logics. In the management of tasks or events this is a primary concern of the A style.

E – Hierarchy: This type of connectivity describes the upwards constraints imposed by parts on the whole, and reciprocal downwards constraints imposed by the whole on parts. All of the standard building blocks of organisms are fitted inside each other in a system of frameworks which mutually require and determine each other. This is the domain of E concern, because events high in the hierarchy can cause big changes lower in the hierarchy, making big gains possible when there are new opportunities to exploit.

I - Traditive Inheritance: The passage of morphological information through time. Traditive inheritance is like interactive constraint, but it is successive rather than simultaneous. It preserves as much information about system linkages from the past – from family or genetic history – as possible, in order to give each part its place in a pattern that works well together, given the interior and exterior perturbations that will threaten a system’s integration. The emphasis on continuity with others puts this in the I domain of concern.

These four basic patterns form a unity, which is the total connectivity of the system. That unity has a more robust ontological status than the four types of order. These four patterns are consequences of a single principle of constraint as it appears locally, globally, across scales and over time. Total connectivity is the whole, the four types of order are its parts. They can be seen as solutions to the problems of connectivity at different powers of resolution. Nevertheless, these are real constraints on evolvable systems, in that a system which violated them would not exhibit the combination of structure and flexibility that underlies evolutionary processes.

These four morphological constraints both enable and canalize evolution, resulting in definite structural forms that characterize phylogeny. Reidl’s work raises the possibility that any adaptive system made up of parts and wholes will show a concern structure. The study of parts and wholes is called mereology, so the structure of concern may be a simple function of adaptive mereology. Thus, any system where parts and wholes are adapted within contexts would show the structure of concern.

1. Riedl, R. (1978). Order in living organisms: A systems analysis of evolution. New York: Wiley.
2. Wagner, G. P., & Laubichler, M. D. (2004). “Rupert Riedl and the re-synthesis of evolutionary and developmental biology: body plans and evolvability.” Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 302(1), 92-102
Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License