Andreas Weber

What factors drove the transformation of the cyanobacterial progenitor of plastids (e.g. chloroplasts) from endosymbiont to bona fide organelle? This question lies at the heart of organelle genesis because, whereas intracellular endosymbionts are widespread in both unicellular and multicellular eukaryotes (e.g. rhizobial bacteria, Chlorella cells in ciliates, Buchnera in aphids), only two canonical eukaryotic organelles of endosymbiotic origin are recognized, the plastids of algae and plants and the mitochondrion. Emerging data on (1) the discovery of non‐canonical plastid protein targeting, (2) the recent origin of a cyanobacterial‐derived organelle in the filose amoeba Paulinella chromatophora, and (3) the extraordinarily reduced genomes of psyllid bacterial endosymbionts begin to blur the distinction between endosymbiont and organelle. Here we discuss the use of these terms in light of new data in order to highlight the unique aspects of plastids and mitochondria and underscore their central role in eukaryotic evolution. BioEssays 29:1239–1246, 2007. © 2007 Wiley Periodicals, Inc.

In contrast to vertical gene transfer from parent to offspring, horizontal (or lateral) gene transfer moves genetic information between different species. Bacteria and archaea often adapt through horizontal gene transfer. Recent analyses indicate that eukaryotic genomes, too, have acquired numerous genes via horizontal transfer from prokaryotes and other lineages. Based on this we raise the hypothesis that horizontally acquired genes may have contributed more to adaptive evolution of eukaryotes than previously assumed. Current candidate sets of horizontally acquired eukaryotic genes may just be the tip of an iceberg. We have recently shown that adaptation of the thermoacidophilic red alga Galdieria sulphuraria to its hot, acid, toxic‐metal laden, volcanic environment was facilitated by the acquisition of numerous genes from extremophile bacteria and archaea. Other recently published examples of horizontal acquisitions involved in adaptation include ice‐binding proteins in marine algae, enzymes for carotenoid biosynthesis in aphids, and genes involved in fungal metabolism.Editor's suggested further reading in BioEssays Jumping the fine LINE between species: Horizontal transfer of transposable elements in animals catalyses genome evolution Abstract.

In this paper I pursue the influences of Jakob von Uexküll’s biosemiotics on the anthropology of Ernst Cassirer. I propose that Cassirer in his Philosophy of the Symbolic Forms has written a cultural semiotics which in certain core ideas is grounded on biosemiotic presuppositions, some explicit (as the “emotive basic ground” of experience), some more implicit. I try to trace the connecting lines to a biosemiotic approach with the goal of formulating a comprehensive semiotic anthropology which understands man as embodied being and culture as a phenomenon of general semioses.

This paper proposes a basic revision of the understanding of teleology in biological sciences. Since Kant, it has become customary to view purposiveness in organisms as a bias added by the observer; the recent notion of teleonomy expresses well this as-if character of natural purposes. In recent developments in science, however, notions such as self-organization (or complex systems) and the autopoiesis viewpoint, have displaced emergence and circular self-production as central features of life. Contrary to an often superficial reading, Kant gives a multi-faceted account of the living, and anticipates this modern reading of the organism, even introducing the term self-organization for the first time. Our re-reading of Kant in this light is strengthened by a group of philosophers of biology, with Hans Jonas as the central figure, who put back on center stage an organism-centered view of the living, an autonomous center of concern capable of providing an interior perspective. Thus, what is present in nuce in Kant, finds a convergent development from this current of philosophy of biology and the scientific ideas around autopoeisis, two independent but parallel developments culminating in the 1970s. Instead of viewing meaning or value as artifacts or illusions, both agree on a new understanding of a form of immanent teleology as truly biological features, inevitably intertwined with the self-establishment of an identity which is the living process.

In this chapter I propose to understand the current paradigm shift in biology as the origination of a biology of subjects. A description of living beings as experiencing selves has the potential to transform the current mechanistic approach of biology into an embodied-hermeneutic one, culminating in a poetics of nature. We are at the right moment for that: The findings of complex systems research, autopoiesis theory, and evolutionary developmental biology are converging into a picture where the living can not longer be described in terms of causal mechanisms (as is, e. g., the Watson-Crick “central dogma”). Instead, organisms bring forth themselves physically and thereby generate a hermeneutic standpoint, interpreting external and internal stimuli interfering with their auto-creation according to embodied values. This can be observed empirically during embryonic develoment, where genetic instructions do not act as orders, but rather as perturbations being interpreted by an auto-maintaining developmental centre. The notion of organic subjectivity opens the living realm to a hermeneutic perspective. Since any encounter has a meaning and is interpreted accordingly, it creates a perspective of innerness or self. This self experiences all external and internal stimuli as values. The innerness is coextensive with the material dimensions of biochemical processes as their other, or symbolic, side. By this process the subjective perspective of organisms is open to other’s experience. Meaning and value become visible, as they are generated in material, embodied form. Instead of being separate from nature as pure “mind” or “language”, man shares with any other being the same “conditio vitae” of experienced meaning and expressive feeling.

In this paper I pursue the influences of Jakob von Uexküll’s biosemiotics on the anthropology of Ernst Cassirer. I propose that Cassirer in his Philosophy of the Symbolic Forms has written a cultural semiotics which in certain core ideas is grounded on biosemiotic presuppositions, some explicit (as the “emotive basic ground” of experience), some more implicit. I try to trace the connecting lines to a biosemiotic approach with the goal of formulating a comprehensive semiotic anthropology which understands man as embodied being and culture as a phenomenon of general semioses.

This paper describes the semiotic approach to organism in two proto-biosemiotic thinkers, Susanne K. Langer and Hans Jonas. Both authors develop ideas that have become central terms of biosemiotics: the organism as subject, the realisation of the living as a closed circular self, the value concept, and, in the case of Langer, the concept of symbol. Langer tries to develop a theory of cultural symbolism based on a theory of organism as a self-realising entity creating meaning and value. This paper deals mainly with what both authors independently call “feeling”. Both authors describe “feeling” as a value-based perspective, established as a result of the active self interest manifested by an organic system. The findings of Jonas and Langer show the generation of a subject pole, or biosemiotic agent, under a more precise accent, as e.g. Uexküll does. Their ideas can also be affiliated to the interpretation of autopoiesis given by the late Francisco Varela (embodied cognition or “enactivism”). A synthesis of these positions might lead to insights how symbolic expression arises from biological conditions of living.

This paper describes the semiotic approach to organism in two proto-biosemiotic thinkers, Susanne K. Langer and Hans Jonas. Both authors develop ideas that have become central terms of biosemiotics: the organism as subject, the realisation of the living as a closed circular self, the value concept, and, in the case of Langer, the concept of symbol. Langer tries to develop a theory of cultural symbolism based on a theory of organism as a self-realising entity creating meaning and value. This paper deals mainly with what both authors independently call “feeling”. Both authors describe “feeling” as a value-based perspective, established as a result of the active self interest manifested by an organic system. The findings of Jonas and Langer show the generation of a subject pole, or biosemiotic agent, under a more precise accent, as e.g. Uexküll does. Their ideas can also be affiliated to the interpretation of autopoiesis given by the late Francisco Varela (embodied cognition or “enactivism”). A synthesis of these positions might lead to insights how symbolic expression arises from biological conditions of living.

In this paper I pursue the influences of Jakob von Uexküll’s biosemiotics on the anthropology of Ernst Cassirer. I propose that Cassirer in his Philosophy of the Symbolic Forms has written a cultural semiotics which in certain core ideas is grounded on biosemiotic presuppositions, some explicit (as the “emotive basic ground” of experience), some more implicit. I try to trace the connecting lines to a biosemiotic approach with the goal of formulating a comprehensive semiotic anthropology which understands man as embodied being and culture as a phenomenon of general semioses.

This paper describes the semiotic approach to organism in two proto-biosemiotic thinkers, Susanne K. Langer and Hans Jonas. Both authors develop ideas that have become central terms of biosemiotics: the organism as subject, the realisation of the living as a closed circular self, the value concept, and, in the case of Langer, the concept of symbol. Langer tries to develop a theory of cultural symbolism based on a theory of organism as a self-realising entity creating meaning and value. This paper deals mainly with what both authors independently call “feeling”. Both authors describe “feeling” as a value-based perspective, established as a result of the active self interest manifested by an organic system. The findings of Jonas and Langer show the generation of a subject pole, or biosemiotic agent, under a more precise accent, as e.g. Uexküll does. Their ideas can also be affiliated to the interpretation of autopoiesis given by the late Francisco Varela . A synthesis of these positions might lead to insights how symbolic expression arises from biological conditions of living