We define the ideal with the property that a real omits all Borel sets in the ideal which are coded in a transitive model if and only if it is an amoeba real over this model. We investigate some other properties of this ideal. Strolling through the "amoeba forest" we gain as an application a modification of the proof of the inequality between the additivities of Lebesgue measure and Baire category.

In the nineteenth century protozoology and early cell biology intersected through the nexus of Darwin's theory of evolution. As single-celled organisms, amoebae offered an attractive focus of study for researchers seeking evolutionary relationships between the cells of humans and other animals, and their primitive appearance made them a favourite model for the ancient ancestor of all living things. Their resemblance to human and other metazoan cells made them popular objects of study among morphologists, physiologists, and even those investigating animal (...) behaviour. The amoeba became the exemplar of the new protoplasmic cell concept of mid-century and because its apparent simplicity made it widely generalizable it became a popular subject in a breadth of experimental investigations and theoretical speculations. It was able to do this because "the amoeba" denotes not a particular organism, but a general type of behaviour common to the cells of a range of protozoa, simple plants and higher animals. Its status as an exemplary cell also rested upon auxiliary philosophical assumptions about what constitutes a primitive characteristic and the thesis that evolution is a progressive development of order from chaos. (shrink)

We show that Σ1 4-Amoeba-absoluteness implies that $\forall a \in \mathbb{R}(\omega^{L\lbrack a \rbrack}_1 < \omega^V_1)$ and, hence, Σ1 3-measurability. This answers a question of Haim Judah (private communication).

In this paper we analyse some notions of amoeba for tree forcings. In particular we introduce an amoeba-Silver and prove that it satisfies quasi pure decision but not pure decision. Further we define an amoeba-Sacks and prove that it satisfies the Laver property. We also show some application to regularity properties. We finally present a generalized version of amoeba and discuss some interesting associated questions.

A fundamental goal of biology is to understand how novel phenotypes evolved through changes in existing genes. The Dictyostelia or social amoebas represent a simple form of multicellularity, where starving cells aggregate to build fruiting structures. This review summarizes efforts to provide a framework for investigating the genetic changes that generated novel morphologies in the Dictyostelia. The foundation is a recently constructed molecular phylogeny of the Dictyostelia, which was used to examine trends in the evolution of novel forms and in (...) the divergence of genes that shape these forms. There is a major trend towards the formation of large unbranched fruiting bodies, which is correlated with the use of cyclic AMP (cAMP) as a secreted signal to coordinate cell aggregation. The role of cAMP in aggregation arose through co‐option of a pathway that originally acted to coordinate fruiting body formation. The genotypic changes that caused this innovation and the role of dynamic cAMP signaling in defining fruiting body size and pattern throughout social amoeba evolution are discussed. BioEssays 29:635–644, 2007. © 2007 Wiley Periodicals, Inc. (shrink)

Ancient pathways promoting unicellularity and multicellularity are associated with cancer, the former being pro‐oncogenic and the latter acting to suppress oncogenesis. However, there are only a limited number of non‐vertebrate models for studying these pathways. Here, we review Dictyostelium discoideum and describe how it can be used to understand these gene networks. D. discoideum has a unicellular and multicellular life cycle, making it possible to study orthologs of cancer‐associated genes in both phases. During development, differentiated amoebae form a fruiting (...) body composed of a mass of spores that are supported atop a stalk. A portion of the cells sacrifice themselves to become non‐reproductive stalk cells. Cheating disrupts the principles of multicellularity, as cheater cells alter their cell fate to preferentially become spores. Importantly, D. discoideum has gene networks and several strategies for maintaining multicellularity. Therefore, D. discoideum can help us better understand how conserved genes and pathways involved in multicellularity also influence cancer development, potentially identifying new therapeutic avenues. (shrink)

Fluid-phase endocytosis (pinocytosis) kinetics were studied inDictyostelium discoideum amoebae from the axenic strain Ax-2 that exhibits high rates of fluid-phase endocytosis when cultured in liquid nutrient media. Fluorescein-labelled dextran (FITC-dextran) was used as a marker in continuous uptake- and in pulse-chase exocytosis experiments. In the latter case, efflux of the marker was monitored on cells loaded for short periods of time and resuspended in marker-free medium. A multicompartmental model was developed which describes satisfactorily fluid-phase endocytosis kinetics. In particular, it (...) accounts correctly for the extended latency period before exocytosis in pulse-chase experiments and it suggests the existence of some sorts of maturation stages in the pathway. (shrink)

This chapter contains sections titled: Individuals and Species Commonalities among Species Individuals within Species Individual Histories and Individual Genomes The Social and Legal Importance of Individuality Human Individuals, Persons, and Rights Implications for Justice.

Whenever the membranes of the egg in which the foetus emerges on its way to becoming a new-born are broken, imagine for a moment that something flies off, and that one can do it with an egg as easily as with a man, namely the hommelette, or the lamella. The lamella is something extra-flat, which moves like the amoeba. It is just a little more complicated. But it goes everywhere. And as it is something - I will tell you shortly (...) why - that is related to what the sexed being loses in sexuality, it is, like the amoeba in relation to sexed beings, immortal - because it survives any division, and scissiparous intervention. And it can turn around. Well! This is not very reassuring. But suppose it comes and envelopes your face while you are quietly asleep... I can't see how we would not join battle with a being capable of these properties. But it would not be a very convenient battle. This lamella, this organ, whose characteristic is not to exist, but which is nevertheless an organ - I can give you more details as to its zoological place - is the libido. It is the libido, qua pure life instinct, that is to say, immortal life, irrepressible life, life that has need of no organ, simplified, indestructible life. It is precisely what is subtracted from the living being by virtue of the fact that it is subject to the cycle of sexed reproduction. And it is of this that all the forms of the objet a that can be enumerated are the representatives, the equivalents. Every word has a weight here, in this deceivingly poetic description of the mythic creature called by Lacan "lamella". Lacan imagines lamella as a version of what Freud called "partial object": a weird organ which is magically autonomized, surviving without a body whose organ it should have been, like a hand that wonders around alone in early Surrealist films, or like the smile in Alice in Wonderland that persists alone, even when the Cheshire cat's body is no longer present: "'All right', said the Cat; and this time it vanished quite slowly, beginning with the end of the tail, and ending with the grin, which remained some time after the rest of it had gone. 'Well! I've often seen a cat without a grin', thought Alice; 'but a grin without a cat! It's the most curious thing I ever saw in my life!'" The lamella is an entity of pure surface, without the density of a substance, an infinitely plastic object that can not only incessantly change its form, but can even transpose itself from one to another medium: imagine a "something" that is first heard as a shrilling sound, and then pops up as a monstrously distorted body. A lamella is indivisible, indestructible, and immortal - more precisely, undead in the sense this term has in horror fiction: not the sublime spiritual immortality, but the obscene immortality of the "living dead" which, after every annihilation, re-composes themselves and clumsily goes on. As Lacan puts it in his terms, lamella does not exist, it insists: it is unreal, an entity of pure semblance, a multiplicity of appearances which seem to envelop a central void - its status is purely fantasmatic. This blind indestructible insistence of the libido is what Freud called "death drive," and one should bear in mind that "death drive" is, paradoxically, the Freudian name for its very opposite, for the way immortality appears within psychoanalysis: for an uncanny excess of life, for an "undead" urge which persist beyond the cycle of life and death, of generation and corruption. This is why Freud equates death drive with the so-called "compulsion-to-repeat," an uncanny urge to repeat painful past experiences which seems to outgrow the natural limitations of the organism affected by it and to insist even beyond the organism's death - again, like the living dead in a horror film who just go on. This excess inscribes itself into the human body in the guise of a wound which makes the subject "undead," depriving him of the capacity to die : when this wound is healed, the hero can die in peace. (shrink)

When are psychologists entitled to call a certain theoretical construct "consciousness?" Over the past few decades cognitive psychologists have reintroduced almost the entire conceptual vocabulary of common sense psychology, but now in a way that is tied explicitly to reliable empirical observations, and to compelling and increasingly adequate theoretical models. Nevertheless, until the past few years most cognitive psychologists and neuroscientists avoided dealing with consciousness. Today there is an increasing willingness to do so. But is "consciousness" different from other theoretical (...) entities like "working memory" or "mental imagery"? Some argue that under no circumstances can empirical science speak of consciousness as such, while others claim that the scientific goal is "knowing what it is like to be a bat" --- to share an organism's conscious experience . The Bat Criterion is ominously reminiscent of the protracted debate on the consciousness of ants and amoebas that caused so much uneasiness in psychology around 1900. It seems to demand that we first solve the mind-body problem as a condition of doing sensible science, and thereby creates the risk of endless, fruitless controversy. The endless philosophical debate about consciousness helped trigger the Behaviorist revolution about 1913, which threw out the baby of consciousness with the bathwater of perennial, circular debate. We've been that way; let's not go back to it. This paper maintains that the position of behavioristic denial is far too restrictive, but that the Bat Criterion is far too demanding --- that in fact, we only need to specify comparable pairs of psychological phenomena that differ only in the fact that one member of any pair is conscious, while the other is not. This "method of contrastive analysis" is a generalization of the experimental method, with consciousness as a variable whose interaction with other psychological and biological phenomena can be assessed in standard ways. As usual in science, this strategy is pragmatic: If it appears to yield sensible results, it can be a stepping-stone toward further understanding . This paper describes five sets of well-established pairs of phenomena that meet these criteria. Others are presented elsewhere, with more of a theoretical interpretation . Here I simply want to show that any adequate theory of conscious experience must satisfy these demanding but achievable empirical constraints. (shrink)

Insights into the intelligence throughout the natural and technical environment, in the fabric of our devices and dwellings, in our clothes, and under our skin. Is there a way to understand the materials that surround us not as passive objects, but as other intelligences interacting with our own? In Parallel Minds, expert in materials science and nanotechnology Laura Tripaldi delivers not only detailed insights into the properties and emergent behaviors of matter as revealed by state-of-the-art chemistry, synthetic biology, and nanotech, (...) but also a rich philosophical reflection that crosses the frontier between nature and culture, where the most cutting-edge scientific syntheses resonate with ancient myth. The result is a technomaterial bestiary full of unexpected encounters with “strange minds”—from cobwebs to kevlar and carbon fibre, from centaurs to amoebas to arachnids, from polycephalic slime to resonating plasmons, from viruses to golems. Parallel Minds reveals the intelligence at large throughout the natural and technical environment, in the fabric of our devices and dwellings, in our clothes, and even under our skin. Full of lateral ideas and unexpected images, Tripaldi’s book imbues the study and synthesis of materials with a new urgency. For not only do the materials that surround us participate actively in the construction of the world in which we live, but harnessing their ability to interact intelligently with their environment could be the key to the future of our species. (shrink)

How do we know what an amoeba looks like? How can doctors see the details of our skeletons and internal organs? All of these things are made possible through the innovations of photography. The author provides a primer on the applications of photography to science as she explores the multiple facets of this complex relationship.

I introduce a new approach to fission puzzles called the Diversified Approach that proceeds by distinguishing different kinds of fission and assimilating each kind to a different ordinary phenomenon, such as breaking apart, replication, or part loss. To illustrate this approach, I apply it to the case of amoebic fission. The upshot is a novel account of amoebic fission according to which the dividing amoeba ceases to exist because it breaks apart. After developing this solution and highlighting some of its (...) advantages, I discuss briefly how the Diversified Approach can be extended to other varieties of fission. (shrink)

We continue the investigation of the Laver ideal ℓ 0 and Miller ideal m 0 started in [GJSp] and [GRShSp]; these are the ideals on the Baire space associated with Laver forcing and Miller forcing. We solve several open problems from these papers. The main result is the construction of models for $t , where add denotes the additivity coefficient of an ideal. For this we construct amoeba forcings for these forcings which do not add Cohen reals. We show that (...) c = ω 2 implies $\operatorname{add}(m^0) \leq \mathfrak{h}$ . We show that b = c, d = c implies $\operatorname{cov}(\ell^0) \leq \mathfrak{h}^+, \operatorname{cov}(m^0) \leq \mathfrak{h}^+$ respectively. Here $\operatorname{cov}$ denotes the covering coefficient. We also show that in the Cohen model $\operatorname{cov}(m^0) holds. Finally we prove that Cohen forcing does not add a superperfect tree of Cohen reals. (shrink)

Based on formal arguments from Zermelo–Fraenkel set theory we develop the environment for explaining and resolving certain fundamental problems in physics. By these formal tools we show that any quantum system defined by an infinite dimensional Hilbert space of states interferes with the spacetime structure M. M and the quantum system both gain additional degrees of freedom, given by models of Zermelo–Fraenkel set theory. In particular, M develops the ground state where classical gravity vanishes. Quantum mechanics distinguishes set-theoretic random forcing (...) such that M and gravitational degrees of freedom are parameterized by extended real line. The large scale smooth geometry compatible with the forcing extensions is one of exotic smoothness structures of \. The amoeba forcing makes the old real line to have Lebesgue measure zero in the extended one. We apply the entire procedure to the cosmological constant problem, especially to discard the zero-modes contributions to the gravitational vacuum density. Moreover, there exists certain exotic smooth \ from which one determines the realistic, agreeing with observation, small value of the vacuum energy density. (shrink)

We hypothesize that aspects of animal multicellularity originated before the divergence of metazoans from fungi and social amoebae. Polarized epithelial tissues are a defining feature of metazoans and contribute to the diversity of animal body plans. The recent finding of a polarized epithelium in the non‐metazoan social amoeba Dictyostelium discoideum demonstrates that epithelial tissue is not a unique feature of metazoans, and challenges the traditional paradigm that multicellularity evolved independently in social amoebae and metazoans. An alternative view, presented (...) here, is that the common ancestor of social amoebae, fungi, and animals spent a portion of its life cycle in a multicellular state and possessed molecular machinery necessary for forming an epithelial tissue. Some descendants of this ancestor retained multicellularity, while others reverted to unicellularity. This hypothesis makes testable predictions regarding tissue organization in close relatives of metazoans and provides a novel conceptual framework for studies of early animal evolution.Editor's suggested further reading in BioEssays Searching for Eve: Basal metazoans and the evolution of multicellular complexity Abstract. (shrink)

“It’s not good enough to say there’s some mechanism such that you start out with amoebas and you end up with us. Everybody agrees with that. The question is in this case in the mechanical details. What you need is an account, as it were step by step, about what the constraints are, what the environmental variables are, and Darwin doesn’t give you that.”.

The hard problem of consciousness is to explain why certain physical states are conscious: why do they feel the way they do, rather than some other way or no way at all? Arthur Reber claims to solve the hard problem. But he does not: even if we grant that amoebae are conscious, we can ask why such organisms feel the way they do, and Reber’s theory provides no answer. Still, Reber’s theory may be methodologically useful: we do not yet (...) have a satisfactory theory of consciousness, but perhaps the study of simple minds is a way to go about finding one. (shrink)

Money and support tend to flow in the direction of economics, science, and other academic departments that demonstrate measurable "progress." The humanities, on the other hand, offer more abstract and uncertain outcomes. A humanist's objects of study are more obscure in certain ways than pathogens and cells. Consequently, it seems as if the humanities never truly progress. Is this a fair assessment? By comparing objects of science, such as the brain, the galaxy, the amoeba, and the quark, with objects of (...) humanistic inquiry, such as the poem, the photograph, the belief, and the philosophical concept, Volney Gay reestablishes a fundamental distinction between science and the humanities. He frees the latter from its pursuit of material-based progress and restores its disciplines to a place of privilege and respect. Using the metaphor of magnification, Gay shows that, while we can investigate natural objects to the limits of imaging capacity, magnifying cultural objects dissolves them into noise. In other words, cultural objects can be studied only within their contexts and through the prism of metaphor and narrative. Gathering examples from literature, art, film, philosophy, religion, science, and psychoanalysis, Gay builds a new justification for the humanities. By revealing the unseen and making abstract ideas tangible, the arts create meaningful wholes, which itself is a form of progress. (shrink)

This chapter includes Margaret Floy Washburn’s discussion of the basis of inferences about animal minds and her discussion of what it is like to be an amoeba.

The process of embryogenesis poses numerous philosophical puzzles. Conceptual difficulties encountered while attempting to clarify the ontological and moral status of the fertilized ovum, for example, are compounded in the minds of some philosophers by the possible occurrence of monozygotic twinning during the earliest stages of embryological development. In light of certain conceptual complexities engendered by this possibility, G.E.M. Anscombe, for example, has come to believe that the pivotal metaphysical query in need of an adequate response is the following: Is (...) the human zygote a single human? The answer to this question is of interest to Anscombe primarily for the role it would play in solving the following puzzle: Suppose that zygote A divides into twins B and B1, such that neither B nor B1 is identical with its twin or with A. It then seems clear that either A, prior to its division, was somehow already B and B1; or A was a single human out of which another human grew ; or A, which was a single human, became two humans, much like an amoeba becomes two amoebae; or A is a "whole human substantial entity". (shrink)

We hypothesize that as one of the most consequential events in evolution, primary endosymbiosis accelerates lineage divergence, a process we refer to as the endosymbiotic ratchet. Our proposal is supported by recent work on the photosynthetic amoeba, Paulinella, that underwent primary plastid endosymbiosis about 124 Mya. This amoeba model allows us to explore the early impacts of photosynthetic organelle (plastid) origin on the host lineage. The current data point to a central role for effective population size (Ne) in accelerating divergence (...) post‐endosymbiosis due to limits to dispersal and reproductive isolation that reduce Ne, leading to local adaptation. We posit that isolated populations exploit different strategies and behaviors and assort themselves in non‐overlapping niches to minimize competition during the early, rapid evolutionary phase of organelle integration. The endosymbiotic ratchet provides a general framework for interpreting post‐endosymbiosis lineage evolution that is driven by disruptive selection and demographic and population shifts. Also see the video abstract here: https://youtu.be/gYXrFM6Zz6Q. (shrink)

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. (shrink)

Philosophers have not taken the evolution of human beings seriously enough. If they did, argues Peter Munz, many long standing philosophical problems would be resolved. One of philosophical concequences of biology is that all the knowledge produced in evolution is a priori, i.e., established hypothetically by chance mutation and selective retention, not by observation and intelligent induction. For organisms as embodied theories, selection is natural and for theories as disembodied organisms, it is artificial. Following Popper, the growth of knowledge is (...) seen to be continuous from the amoeba to Einstein'. Philosophical Darwinism throws a whole new light on many contemporary debates. It has damaging implications for cognitive science and artificial intelligence, and questions attempts from within biology to reduce mental events to neural processes. More importantly, it provides a rational postmodern alternative to what the author argues are the unreasonable postmodern fashions of Kuhn, Lyotard and Rorty. (shrink)

Philosophers have not taken the evolution of human beings seriously enough. If they did, argues Peter Munz, many long-standing philosophical problems would be resolved. One of the philosophical consequences of biology is that all the knowledge produced in evolution is a priori established hypothetically by chance mutation and selective retention rather than by observation and intelligent induction. For organisms as embodied theories, selection is natural. For theories as disembodied organisms, it is artificial. Following Karl Popper, the growth of knowledge is (...) seen to be continuous from "the amoeba to Einstein." Philosophical Darwinism brings perspective to contemporary debates. It has far-reaching implications for cognitive science and artificial intelligence, and questions attempts from the field of biology to reduce mental events to neural processes. Most importantly, it provides a rational postmodern alternative to what the author views as the unreasonable postmodern theories of Kuhn, Lyotard, and Rorty. (shrink)

Natural selection is often envisaged as the ultimate cause of the apparent rationality exhibited by organisms in their specific habitat. Given the equivalence between selection and rationality as maximizing processes, one would indeed expect organisms to implement rational decision-makers. Yet, many violations of the clauses of rationality have been witnessed in various species such as starlings, hummingbirds, amoebas and honeybees. This paper attempts to interpret such discrepancies between economic rationality and biological rationality. After having distinguished two kinds of rationality we (...) introduce irrationality as a negation of economic rationality by biologically rational decision-makers. Focusing mainly on those instances of irrationalities that can be understood as exhibiting inconsistency in making choices, i.e. as non-conformity of a given behaviour to axioms such as transitivity or independence of irrelevant alternatives, we propose two possible families of Darwinian explanations that may account for these apparent irrationalities. First, we consider cases where natural selection may have been an indirect cause of irrationality. Second, we consider putative cases where violations of rationality axioms may have been directly favored by natural selection. Though the latter cases seem to clearly contradict our intuitive representation of natural selection as a process that maximizes fitness, we argue that they are actually unproblematic; for often, they can be redescribed as cases where no rationality axiom is violated, or as situations where no adaptive solution exists in the first place. (shrink)

Philosophers have not taken the evolution of human beings seriously enough. If they did, argues Peter Munz, many long standing philosophical problems would be resolved. One of philosophical concequences of biology is that all the knowledge produced in evolution is a priori, i.e., established hypothetically by chance mutation and selective retention, not by observation and intelligent induction. For organisms as embodied theories, selection is natural and for theories as disembodied organisms, it is artificial. Following Popper, the growth of knowledge is (...) seen to be continuous from the amoeba to Einstein'. Philosophical Darwinism throws a whole new light on many contemporary debates. It has damaging implications for cognitive science and artificial intelligence, and questions attempts from within biology to reduce mental events to neural processes. More importantly, it provides a rational postmodern alternative to what the author argues are the unreasonable postmodern fashions of Kuhn, Lyotard and Rorty. (shrink)

We investigate some versions of amoeba for tree-forcings in the generalized Cantor and Baire spaces. This answers [10, Question 3.20] and generalizes a line of research that in the standard case has been studied in [11], [13], and [7]. Moreover, we also answer questions posed in [3] by Friedman, Khomskii, and Kulikov, about the relationships between regularity properties at uncountable cardinals. We show ${\bf{\Sigma }}_1^1$-counterexamples to some regularity properties related to trees without club splitting. In particular we prove a strong (...) relationship between the Ramsey and the Baire properties, in slight contrast with the standard case. (shrink)

The two vegetative cell types of the acellular slime mould Physarum polycephalum ‐ amoebae and plasmodia ‐ differ greatly in cellular organisation and behaviour as a result of differences in gene expression. The development of uninucleate amoebae into multinucleate, syncytial plasmodia is under the control of the mating‐type locus matA, which is a complex, multi‐functional locus. A key period during plasmodium development is the extended cell cycle, which occurs in the developing uninucleate cell. During this long cell cycle, (...) many of the changes in cellular organisation that accompany development into the multinucleate stage are initiated including, for example, alterations in microtubule organisation. Genes have been identified that show cell‐type specific expression in either amoebae or plasmodia and many of these genes alter their pattern of expression during the extended cell cycle. With the introduction of a DNA transformation system for P. polycephalum, it is now possible to investigate the functions of genes in the vegetative cell types and their roles in the cellular reorganisations accompanying development. (shrink)

“It’s not good enough to say there’s some mechanism such that you start out with amoebas and you end up with us. Everybody agrees with that. The question is in this case in the mechanical details. What you need is an account, as it were step by step, about what the constraints are, what the environmental variables are, and Darwin doesn’t give you that.”.

“It’s not good enough to say there’s some mechanism such that you start out with amoebas and you end up with us. Everybody agrees with that. The question is in this case in the mechanical details. What you need is an account, as it were step by step, about what the constraints are, what the environmental variables are, and Darwin doesn’t give you that.”.

The author defends the naturalizing program of the notion of representation against the primitivist view according to which the notion of representation as belonging to psychology as a mature science is irreducible. First, the author concedes that the original teleological project trivializes the concept of representation by applying it to bacteria, protozoa, amoeba, when the best available explanation is the assumption that primitive organisms and artifacts are merely indicating proximal stimulation rather than representing the distal causes of stimulation. Yet, the (...) author does not believe that this presents an unsurmountable obstacle for the naturalizing program when what is in question is genuine sensory representation, namely perception. In the author’s view, what matters for the naturalizing program are not cases in which the concept of representation is misemployed, but rather cases in which the focus is genuine sensory representation, that is, genuine perceptions; or so he shall argue. (shrink)

Microorganisms luxuriate in, plants push through, the humus, that is, the corpses of plants, insects, birds and mammals. Insects, fish, birds, and mammals nourish themselves with the flesh of plants on hand, and also with that of insects, fish, birds, and mammals. In the natural world, everything assimilates and is assimilated. Every animal, from amoebas to the blue whales, feels moments of fear, for they know they are vulnerable and mortal. As they eat what is at hand they sense that (...) what will eat them is already at hand. (shrink)

Microorganisms luxuriate in, plants push through, the humus, that is, the corpses of plants, insects, birds and mammals. Insects, fish, birds, and mammals nourish themselves with the flesh of plants on hand, and also with that of insects, fish, birds, and mammals. In the natural world, everything assimilates and is assimilated. Every animal, from amoebas to the blue whales, feels moments of fear, for they know they are vulnerable and mortal. As they eat what is at hand they sense that (...) what will eat them is already at hand. (shrink)

Starvation induces free‐living Dictyostelium discoideum amoebae to form slugs that typically contain 100,000 cells. Only recently have sufficient clues become available to suggest how coordinated cell actions might result in slug movement. We propose a “squeeze‐pull” model that involves circumferential cells squeezing forward a cellular core, followed by pulling up of the rear. This model takes into account the different classes of cells in the slug; it is proposed that prestalk cells are engines and prespore cells are the cargo.

Microscopy has revealed tremendous diversity of bacterial and eukaryotic forms. Recent molecular analyses show discordance in estimates of biodiversity between morphological and molecular analyses. Moreover, phylogenetic analyses of the diversity of microbial forms reveal evidence of convergence at scales as deep as interdomain: morphologies shared between bacteria and eukaryotes. Here, we highlight examples of such discordance, focusing on exemplary lineages such as testate amoebae, ciliates, and cyanobacteria. These have long histories of morphological study, enabling deeper analyses on both the (...) molecular and morphological sides. We discuss examples in two main categories: (i) morphologically identical (or highly similar) individuals that are genetically distinct and (ii) morphologically distinct individuals that are genetically the same. We argue that hypotheses about discordance can be tested using the concept of neutral morphologies, or more broadly neutral phenotypes, as a null hypothesis. -/- . (shrink)

Entamoeba histolytica is a protozoan parasite of humans, and the causitive agent of intestinal amebiasis. The disease‐causing stage of the parasite is an osmotically sensitive ameboid form, which differentiates into a thick‐walled cyst for transmission from person to person. The conditions within the human intestine that induce encystment of the amoeba are unknown, but studies using an amoebic parasite of reptiles are now yielding information about the molecules and host:parasite interactions involved in the process. An understanding of the amoeba's obligatory (...) encystment pathway should provide an approach for interrupting the transmission of this parasite, for which there is currently no vaccine. (shrink)

Recent developments in cognitive science provide compelling leads that need to be interpreted and synthesized within the context of semiotic and biosemiotic principles. To this end, we examine the impact of the mind-body unity on the sorts of choices that an organism is predisposed to making from its Umwelt. In multicellular organisms with brains, the relationship that an organism has with its Umwelt impacts on neural plasticity, the functional specialisations that develop within the brain, and its behaviour. Clinical observations, such (...) as those recorded by Norman Doidge, as well as historical observations from outside the field of semiotics (Plato, Aristotle, Hume) shed further light on this process, and serve to further substantiate our semiotic and biosemiotic paradigm. Our analysis develops a rather limited associationism (with reference to Peirce’s categories) into a more general and robust interpretation that is applicable to all mind-bodies, whether they be neurons, paramecia and amoebae, or humans, cats and dogs. Biosemiotics is a more universal semiotics that takes us beyond the confines of anthropocentrism, because it recognizes the role of the body in shaping Mind. (shrink)

We investigate two variants of splitting tree forcing, their ideals and regularity properties. We prove connections with other well‐known notions, such as Lebesgue measurablility, Baire‐ and Doughnut‐property and the Marczewski field. Moreover, we prove that any absolute amoeba forcing for splitting trees necessarily adds a dominating real, providing more support to Hein's and Spinas' conjecture that.

Streamer F mutants have been found to be useful tools for studying the pathway of signal transduction leading to chemotactic cell movement. The primary defect in these mutants is in the structural gene for the cyclic GMP specific phosphodiesterase. This defect allows a larger and prolonged peak of cyclic GMP to be formed in response to the chemotactic stimulus, cyclic AMP. This characteristic aberrant pattern of cyclic GMP accumulation in the streamer F mutants has been correlated with similar patterns of (...) changes in the influx of calcium from the medium, myosin II association with the cytoskeleton, myosin phosphorylation and a decrease in speed of movement of the amoebae. From these studies a sequence of events can be deduced that leads from cell surface cyclic AMP stimulation to cell polarization prior to movement of the amoebae in response to the chemotactic stimulus. (shrink)

A very rapid cellular event that follows chemotactic stimulation of leucocyte and cellular slime mould amoebae is a massive polymerization of G to F actin and its association with the cytoskeleton. In the cellular slime moulds this event occurs within 3–5 sec of cell surface binding of chemoattractants. It is correlated with rapid pseudopodium extension and may be a cell orientation mechanism. Curiously, before an amoebae moves away in the direction of its new pseudopodium it rounds up or (...) “cringes” for 10–20 sec, an event correlated with a massive actin depolymerization. Transduction of the chemotactic signal involves Ca2+ release from internal stores by inositol trisphosphate. (shrink)

Why do minds exist? How did mud and stone develop into beings that can experience longing, regret, love, and compassion-beings that are aware of their own experience? Until recently, science offered few answers to these existential questions. Journey of the Mind is the first book to offer a unified account of the mind that explains how consciousness, language, the Self, and civilization emerged incrementally out of chaos. The journey begins three billion years ago with the emergence of the simplest possible (...) mind, a nanoscopic archeon, then ascends through amoebas, worms, frogs, birds, monkeys, and AI, examining successively smarter ways of thinking. The authors explain the mathematical principles generating conscious experience and show how these principles led cities and democratic nations to develop new forms of consciousness-the self-aware "superminds." Journey of the Mind concludes by contemplating a higher stage of consciousness already emerging-and the ultimate fate of all minds in the universe. (shrink)

The plasmodium of _Physarum polycephalum_ is a unicellular and multinuclear giant amoeba with computational abilities. The plasmodium has been widely used as a model organism in the field of bio-computing; however, its ability to perform computation related to its biological nature itself in the essential sense has not yet been fully realized. Therefore, in this study, we focused on the phenomenon in which a plasmodium trapped in a closed space surrounded by repellent substances escapes from the field by changing its (...) own behavior rules. We demonstrated that this phenomenon is bio-computationally important in that it may enable the implementation of biological characteristics in computing. (shrink)