Contribution to the Whole (H). Can Squids Show us Anything that We did not know Already?

Abstract

For a multicellular organism to proceed from egg to adult it must: (i) undergo cell division, (ii) differentiate, (iii) remain a unified whole (H o ). These requirements are at right angles to each other. The first two are achieved through hierarchical processes (vertical control) that are relatively well understood, the third through non-hierarchical processes (horizontal control) physiological evidence for which is abundant, though not widely recognized as a form of control. The essay gives an example of a tissue -the skin of a living squid -whose horizontal network properties come to light when nervous (vertical) control is removed. It offers the name homeotaxy or 'peer conformity' for the general principle (allied to the community effect, Gurdon 1988) that constrains the parts of the whole to be in the same state within any given layer of the networkwhere layers correspond to ontogenetic stages in the development of the tissue -and discusses the question of a need and a name for this principle in Biology.Savouring of an intangible 'holism' and of Driesch's dubious 'entelechy', the old question of how it is that the organism behaves as a whole, and not just as a collection of parts, can not be said to be of major concern to today's biologists. One obstacle is that holistic concepts are notoriously difficult to formulate; the words and concepts available for dealing with wholes are perceived as inadequate; we seem to have advanced little beyond the broad statements of the organismal and Gestalt schools. Another is the sheer success of reductionist methodology allied to molecular technologies. While this essay is essentially about the first of these problems, it is heavily influenced by the existence of the second.As a working 'whole animal' biologist, I see it as a question of controls, and seek a pragmatic way round the problem by asserting, on general biological grounds and as far as possible in non-technical language, some simple principles amply demonstrable in living things.To pose the question about wholes and parts in a dynamic form with reasonable chance of being understood by seminar audiences, I have been asking it in a context with which all students and practitioners in the life sciences should be more or less familiar. What is it that holds the blastomeres together so that

How Nervous Systems Evolve in Relation to Their Embodiment: What We Can Learn from Octopuses and Other Molluscs

“…Its self-organized behavior is reminiscent of case V of the traveling wave predicted by Allen Turing's famous reaction-diffusion model to explain the self-regulated formation of biological patterns [reviewed by Kondo and Miura, 2010]. Packard [2006] already used the chromatophore system to demonstrate what he has termed 'horizontal control', a very similar idea to what I am suggesting here, i.e. the self-control property of a system when separated from the higher control.…”

“…This chromatophore system, an image-generating motor system separate from the neuromuscular motor system, is unique to the modern cephalopods [Hanlon and Messenger, 1996;Packard, 2006]. Skin colors can change rapidly due to neural signals, which cause radial muscle cells to contract.…”

“…The interactions between the chromatophores leading to this self-organized behavior are not entirely understood, but they may be mediated by electrical coupling between the muscles [Packard, 2006]. It is conceivable that, as suggested by the concept of embodied organization, these internal self-organization properties of the chromatophore system simplify its motor control, since the central commands may make use of these basic patterns of behavior.…”

11 Theories of the development of human communication

“…From this we infer that the function of intelligence in the regulation of the vitality of an animal, including its communication of purposes, feelings and understandings to other individuals in a shared world for cooperative goals, is to create and propagate its ways of moving to use its accessible world in self-sustaining ways. Regulation of vitality and agency of the body is the adaptive function of the animal's nervous system, in all its parts, and as a whole sensory-motor Self (Sherrington, 1906;Merker, 2005;Packard, 2006;Northoff and Panksepp, 2008).…”

Evolution ‘on purpose’: how behaviour has shaped the evolutionary process

“…Indeed, the cybernetic model also encompasses processes that conform to the paradigm of ‘distributed control’ or ‘horizontal control’. Some examples include bacterial colonies (Shapiro, ), Cnidaria (Mackie, ; Packard, ), honeybees (Seeley, , ), army ants (Franks, ; Hölldobler & Wilson, ), slime moulds (Bonner, ), and, of course, humans. Indeed, Powers and various colleagues have devoted many years to developing what he calls ‘Perceptual Control Theory’, which melds cybernetics and human psychology .…”