Developmental biology is the science of explaining how a variety of interacting processes generate an organism’s heterogeneous shapes, size, and structural features that arise on the trajectory from embryo to adult, or more generally throughout a life cycle. It represents an exemplary area of contemporary experimental biology that focuses on phenomena that have puzzled natural philosophers and scientists for more than two millennia.

Comprehending the origin of marine invertebrate larvae remains a key domain of research for evolutionary biologists, including the repeated origin of direct developmental modes in echinoids. In order to address the latter question, we surveyed existing evidence on relationships of homology between the ectoderm territories of two closely related sea urchin species in the genus Heliocidaris that differ in their developmental mode. Additionally, we explored a recently articulated idea about homology called ‘organizational homology’ (Muller 2003. In: Muller GB, Newman SA, (...) editors. Origination of organismal form: beyond the gene in developmental and evolutionary biology. Cambridge, MA: A Bradford Book, The MIT Press. p 51–69. ) in the context of this specific empirical case study. Applying the perspective of organizational homology to our experimental system of congeneric echinoids has led us to a new hypothesis concerning the ectoderm evolution in these species. The extravestibular ectoderm of the direct developer Heliocidaris erythrogramma is a novel developmental territory that arose as a fusion of the oral and aboral ectoderm territories found in indirect developing echinoids such as Heliocidaris tuberculata. This hypothesis instantiates a theoretical principle concerning the origin of developmental modules, ‘integration’, which has been neglected because the opposite theoretical principle, ‘parcellation’, is more readily observable in events such as gene duplication and divergence (Wagner 1996. Am Zool 36:36–43). J. Exp. Zool. (Mol. Dev. Evol.) 306B:18– 34, 2006. (shrink)

The star-nosed mole is aptly named. Its distinctive snout consists of 22 tendrils ringing a pair of nostrils and, from some angles, the entire setup resembles a misshapen star. The tendrils are fleshy and look a bit like fingers, and, like fingers, they have a certain dexterity. But why? Why does the mole have such a singular appendage as opposed to something more ordinary? What is the function or purpose of this bizarre structure? From the dedicated work of Ken Catania, (...) of Vanderbilt University, and colleagues, it appears that the appendage facilitates rapid handling of small prey items, making it advantageous for an organism whose diet consists of tiny invertebrates. We might therefore hazard that this feature arose evolutionarily because it conferred this benefit. But the matter is difficult to resolve, because current utility does not permit a straightforward inference of a reason for existence. -/- A correction has been published: BioScience, Volume 72, Issue 7, July 2022, Page 708. (shrink)

Duty or Pleasure? The new bestseller from one of Britain's most pre-eminent, and arguably best known, philosophers.

Among the most important questions still facing human enquiry are those about the mind and its place in nature. What is mind, and what is it relation to body? How should we best understand our common sense concepts of such mental phenomena as belief, desire, intention, emotion, reason and memory? How does the grey matter of the brain give rise to our rich and vivid experiences of colour, sound, texture, taste and smell?

Scientific description of Nature is here based on geometry, number and energy. Geometry and number are the two only forms of our mind by which we describe Nature. Energy is here considered as the ultimate entity, which in physics is defined by the help of six propreties. The author holds that for an adequate description of physical Nature seven propreties of energy are required and eight are necessary in biology adding the holistic tendencies. On this basis an attempt is made (...) to show that holism is a scientific theory. As we can only perceive geometry and number, holistic propreties as such cannot be dealt with, we can only study the underlying physico-chemical manifestation. There are three holistic principles: 1) Interaction of parts leads to neocreation of propreties; this interaction can only be energetic. 2) The propreties of the whole are not potentially contained in the propreties of the parts. 3) The whole is more than the sum of its parts. Close interaction means fields of force and organisation, which implies that holism is organismic. The second principle is a safeguard against all unwarranted extrapolation. The whole and its parts only have additive propreties in common. Thus it is impossible to derive a macroscopic deterministic world from a microscopic undeterministic world because determinism is additive. The third principle is opposed to all attempts to describe holisation on a logical or mathematical basis. There is holisation in time and holisation in space and the latter can be subdivided into three groups according to their type of wholeness. Energy acts on energy and not on wholeness. All energetic interference with the basis has a holistic repercussion. The question of the egg and epigenetic organogenesis are also discussed from a holistic point of view.Naturbeschreibung ist hier auf Geometrie, Zahl und Energie begründet. Geometrie und Zahlenmässigkeit sind die einzigen Formen unseres Geistes durch die wir die Natur beschreiben. Energie, hier als Grundstein der Welt betrachtet, wird in der Physik durch sechs Eigenschaften definiert; zur vollständigen Beschreibung der physischen Welt seien aber sieben notwendig, während in der Biologie acht Eigenschaften nötig sind, indem Ganzheitsschöpfung als achte zählt. Auf dieser Basis wird gezeigt, dass der Holismus eine wissenschaftliche Theorie ist. Da wir nur Geometrie und Zahlenmässigkeit in der Natur erfassen, so können die holistischen Eigenschaften nicht direkt als solche betrachtet werden, sondern immer nur die ihnen zu Grunde liegenden physiko-chemischen Erscheinungen. Es gibt drei holistische Prinzipien: 1) Gegenseitige Beeinflussung führt zu Ganzheitseigenschaften. Beeinflussung kann nur energetisch sein. 2) Die Eigenschaften der Ganzheit sind nicht potential in den Eigenschaften der Teile enthalten. 3) Das Ganze ist mehr als die Summe seiner Teile. Gegenseitige Beeinflussung bedingt Kraftfelder und diese wieder Organisation. und so ist denn der Holismus seinem Wesen nach organismisch. Das zweite Prinzip legt Verwahrung gegen unstatthafte Extrapolation ein. Das Ganze und seine Teile haben nur additive Eigenschaften im gemein. Es ist also unmöglich eine deterministische makroskopische Welt von einer undeterministischen mikrophysischen abzuleiten weil Determinismus additiv ist. Das dritte Prinzip verwehrt sich gegen alle Anwendung von Logik und Mathematik zur Erklärung oder Beschreibung von Holisation . Es gibt Holisation 1) in der Zeit, 2) im Raum. Im Raum unterscheiden sich die Holisationen nach dem Wirkungskreis der Kraftfelder oder durch Abwesenheit solcher. Dies ist eine neue Aufteilung der Welt nach dem Wesen der Ganzheit. Die Einwirkung der Energie auf die Ganzheit ist mikrophysisch. Energie wirkt auf Energie und nicht auf die Ganzheit als solche. Jede energetische Einwirkung besitzt jedoch eine holistische Auswirkung. Das Problem der Eizelle und der epigenetischer Entwicklung wird auch besprochen. (shrink)