Turtles are among the most intriguing amniotes but their communication and signaling have rarely been studied. Traditionally, they have been seen as basically just silent armored ‘walking stones’ with complex physiology but no altruism, maternal care, or aesthetic perception. Recently, however, we have witnessed a radical change in the perception of turtle behavioral and cognitive skills. In our study, we start by reviewing some recent findings pertaining to various highly developed behavioral and cognitive patterns with special emphasis on turtles. Then (...) we focus on freshwater turtles and use data about their sexual behavior and size sexual dimorphism to test whether conspicuous coloration of the head is in these animals related to sexual processes. We found that absence of aggressive mating behavior is statistically associated with the presence of conspicuous coloration on turtles’ heads. It also seems that while species with female-biased SSD are characterised by conspicuously colored head ornaments, in species with male-biased SSD conspicuous coloration is absent. Unlike large females, males thus seem to be under pressure to develop conspicuous coloration and engage in non-aggressive behavior using signaling to succeed in courtship. And finally, we discuss possible roles of head color patterns in turtle communication during mating. (shrink)

Many biologists still believe in a sort of post-Cartesian foundation of reality wherein objects are independent of subjects which cognize them. Recent research in behaviour, cognition, and psychology, however, provides plenty of evidence to the effect that the perception of an object differs depending on the kind of animal observer, and also its personality, hormonal, and sensorial set-up etc. In the following, I argue that exposed surfaces of organisms interact with other organisms’ perception to form semiautonomous relational entities called semantic (...) organs, which participate in biological reality as discrete heritable evolutionary units. The inner dimensions and potentialities of an organism can enter the senses of another living being when effectively expressed on the outer surfaces of the former and meaningfully perceived by the latter. Semantic organs have three basic sources of variability: intrinsic, i.e., genetic, epigenetic, and developmental processes; extrinsic, meaning the biotic and abiotic environmental conditions which affect the developmental generators of intrinsic variability; and perceptual, stemming from differences in the subject-specific interpretation of a SO’s structural basis. Extrinsic and intrinsic sources of variability are, however, just precursors to semantic organs. SOs are relational entities which always come into existence through an act of perception and their actual form depends both on the physical potentialities of the bearer and the species- or group-specific interpretation of the receiver. (shrink)

In the Preface of Animal Species and Evolution (1963), I wrote that it was "an attempt to summarize and review critically what we know about the biology and genetics of animal species and their role in evolution." The result was a volume of XIV ...

At least 22 concepts of species are in use today and many of these are notably incompatible in their accounts of biological diversity. Much of the traditional turmoil embodied in the species problem ultimately derives from the packaging of inappropriate criteria for species into a single concept. This results from a traditional conflation of function of concepts with their applications, definitions with concepts, taxonomic categories with groups, and the ontological status of real species with teleological approaches to recover them. Analogous (...) to classifications of supraspecific taxa, our forging inappropriate and ambiguous information relating to theoretical and operational discussions of species ultimately results in a trade-off between convenience, accuracy, precision, and the successful recovery of natural biological diversity. Hence, none of these expectations or intentions of species or classifications is attainable through composite, and possibly discordant, concepts of biological diversity or its descent. Reviewing and evaluating the concepts of species for their theoretical and operational qualities illustrates that a monistic, primary concept of species, applicable to the various entities believed to be species, is essential. This evaluation reveals only one theoretical concept as appropriate for species, the Evolutionary Species Concept. This conceptualization functions as a primary concept and is essential in structuring our ideas and perceptions of real species in the natural world. The remaining concepts are secondary, forming a hierarchy of definitional guidelines subordinate to the primary concept, and are essential to the study of species in practice. Secondary concepts should be used as operational tools, where appropriate, across the variance in natural diversity to discover entities in accord with the primary concept. Without this theoretical and empirical structuring of concepts of species our mission to achieve reconciliation and understanding of pattern and process of the natural world will fail. (shrink)

Argues for the primacy of the phylogenetic system as the general reference system in biology. This book, first published in 1966, generated significant controversy and opened possibilities for evolutionary biology.

This paper develops the ideas of the Swiss zoologist Adolf Portmann or, more precisely, his concept of organic self-representation, wherein Portmann considered the outer surface of living organisms as a specific organ that serves in a self-representational role. This idea is taken as a starting point from which to elaborate Portman’s ideas, so as to make them compatible with the theoretical framework of biosemiotics. Today, despite the many theories that help us understand aposematism, camouflage, deception and other phenomena related to (...) the category of mimicry, there still is a need for a general theory of self-representation that would re-synthesize evolutionary, morphogenetic and semiotic aspects of the surface of organisms. Here, Adolf Portmann’s concept of self-representation is considered as an important step towards the biosemiotics of animal form. (shrink)

The genetic code appeared on Earth with the first cells. The codes of cultural evolution arrived almost four billion years later. These are the only codes that are recognized by modern biology. In this book, however, Marcello Barbieri explains that there are many more organic codes in nature, and their appearance not only took place throughout the history of life but marked the major steps of that history. A code establishes a correspondence between two independent 'worlds', and the codemaker is (...) a third party between those 'worlds'. Therefore the cell can be thought of as a trinity of genotype, phenotype and ribotype. The ancestral ribotypes were the agents which gave rise to the first cells. The book goes on to explain how organic codes and organic memories can be used to shed new light on the problems encountered in cell signalling, epigenesis, embryonic development, and the evolution of language. (shrink)

Any biological species of biparental organisms necessarily includes, and is fundamentally dependent on, sign processes between individuals. In this case, the natural category of the species is based on family resemblances, which is why a species is not a natural kind. We describe the mechanism that generates the family resemblance. An individual recognition window and biparental reproduction almost suffice as conditions to produce species naturally. This is due to assortativity of mating which is not based on certain individual traits, but (...) on the difference between individuals. The biosemiotic model described here explains what holds a species together. It also implies that boundaries of a species are fundamentally fuzzy, and that character displacement occurs in case of sympatry. Speciation is a special case of discretisation that is an inevitable result of any communication system in work. The biosemiotic mechanism provides the conditions and communicative restrictions for the origin and persistence of diversity in the realm of living systems. (shrink)