Lietuvos chirurgija

Abstract Cells are central for life, starting some 3.7 billion years ago with the assembly of the first primordial cells in the primeval and prebiotic oceans of the young Earth’s environment. Details of this abiogenesis are still missing but since the first competent, self-reproductive cell emerged, life has been based on continuous cell divisions. Accordingly, all present cells can be traced directly to the very first cells. Our senomic concept of cell sentience based on bioelectromagnetic fields postulated that all cells are sentient and that life and sentience are coterminous. Archaea and bacteria are the most ancient cellular organisms and they still exhibit a unicellular lifestyle. Some two billion years after the emergence of life on Earth, eukaryotic cells were symbiotically assembled from archaeal and bacterial cells. Eukaryotic cells later coalesced to form true multicellular organisms in partnership with bacteria and archaea, forming holobionts, including fungi, plants, and animals. All organisms living presently are integrated into the Earth’s biosphere, which permeates all three major ecological habitats: the geosphere, hydrosphere, and the atmosphere. Coexistence of such vast assemblies of collaborating cells necessitates a highly elevated level of integration, which originates at the level of the senomic spheres of individual prokaryotic and eukaryotic cells across the whole of Earth’s biosphere corresponding to the hypothetical Gaia concept.

Abstract We are currently in the midst of what I call biology’s Einstein moment. This is the rejection of absolute biological history, the idea that there is an invariant, privileged biological history against which other histories are measured or deviate from. Instead, biologists must specify theoretically and empirically motivated frames of lineal reference. This is already informing and advancing biological practice, theory, methods, and more, and is a significant and important feature of contemporary biology. Here I argue that it is worth identifying and naming this shift, and encouraging a deeper and broader embrace of it.

Abstract In this article, we revisit the longstanding debate of whether there is a pattern in the evolution of organisms towards greater complexity, and how this hypothesis could be tested using an interdisciplinary lens. We argue that this debate remains alive today due to the lack of a quantitative measure of complexity that is related to the teleonomic (i.e., goal-directed) nature of living systems. Further, we argue that such a biological measure of complexity can indeed be found in the vast literature produced within life history theory. We propose that an ideal method to quantify this complexity lies within life history strategies (i.e., schedules of survival and reproduction across an organism’s life cycle), as it is precisely these strategies that are under selection to optimize the organism’s fitness. In this context, we set an agenda for future steps: (1) how this complexity can be measured mathematically, and (2) how we can engage in a comparative analysis of this complexity across species to investigate the evolutionary forces driving increases or, for that matter, decreases in teleonomic complexity.

AbstractSex is fundamental to many organisms. It is through sexual reproduction that humans, and many metazoans (multicellular eukaryotes in the animal kingdom), propagate our species. For more than 150 years, sexual reproduction within metazoans has been understood to rely on the existence of a discrete category of cells (germ cells) that are usually considered uniquely separate from all other cells in the body (somatic cells), and which form a cell lineage (germline) that is sequestered from all somatic cell lineages. The consideration of germ cells and germline as the lone source of reproductive potential within metazoans has allowed many investigators to place the hereditary and evolutionary burdens of sexually reproducing lineages solely within these cells and cell lineages, making them central to many important topics within biology, such as units of selection, transmission and population genetics, Darwinian evolution, and individuality. Regarding these topics, there is a predominant and shared understanding of germ cells, somatic cells, and the ways in which these two relate to each other that is rarely critically evaluated. In this article, I lay out how germ cells and germline within metazoans are understood by a majority of scientists and philosophers, both now and historically, by sketching out what I call the predominant epistemic framework of germ. I show how this framework conflicts with empirical evidence, propose a series of revisions to realign it with this evidence, and indicate why such revisions are urgently needed by highlighting the case of somatic cell genome editing.

AbstractThe organism is the central entity in biological science. However, consensus with regard to the definition of the underlying concept is lacking. Moreover, several ambiguous life forms exist that challenge current definitions of the term. Based on a comprehensive analysis of the available literature, we provide an overview of the criteria and approaches that have been previously used to define organismality. In addition, we highlight non-paradigmatic biological entities to identify problems that challenge definitions of organismal units. To address these issues, we propose a cross-disciplinary definition of the organism concept and provide a list of key criteria that allow both paradigmatic and non-paradigmatic cases to be unequivocally classified. In this way, our work not only provides newcomers with an overview of this exciting field, but also enhances communication across disciplines.

AbstractSince the onset of the digital revolution, humankind has experienced an unprecedented acceleration of changes triggered by technological advancements. Frequently used digital media have unquestionably penetrated our everyday life, shaping human cognition in multiple ways. The rise of artificial intelligence, which coevolved with a new, interdisciplinary field of cognitive science, has amplified these effects, contributing new ways of affecting human society, in terms of efficient human-machine interaction and knowledge generation and accumulation, at an exponential rate. Simultaneously, cultural shifts driven by globalization and social media have fostered new modes of communication, identity formation, and knowledge dissemination on a global scale. Understanding the intricate dynamics of techno-cultural evolution and its influence on cognition is essential for comprehending the contemporary society and preparing it for the future challenges. We need to adapt for the current and future information environments and digital landscapes, improving human resilience to new technologies and addressing core human vulnerabilities. Thanks to human flexibility, enabled by neural plasticity, that may be feasible, ideally combined with alleviation of known negative effects of digital technologies.

AbstractCancers are hard to treat, and this is largely because cancer cells evolve and diversify through space and time, in patients. The study of clonal evolution relies on the study of cancer cell lineages, and the cutting of these lineages into clones, each clone representing cancer cells with distinctive properties relevant to cancer development and treatment. This notion of clone implies a (set of) simplification(s) that misrepresents the reality. The simplification has been useful and productive, but I argue that maintaining a critical awareness of what is done through this simplification can also be useful and productive. I distinguish three types of simplifications and show that each can offer a panel of therapeutic alternatives that may complement our arsenal of strategies in the battle against clones. The clinical challenge of better treating cancer partly relies on better defining (delineating) clones, but also partly on the more fundamental way we conceive clones. With or without changing the definition, changes in the way we conceive of clones induce changes in the way we treat clones.

One of the consequences of global warming is reduced final body sizes in animals of different orders, mainly in aquatic ectotherms like fish or water-breathing invertebrates. In this article, we identify August Pütter (1879–1929) as the originator of what is now called the “temperature–size rule” and as the first physiologist to develop a mechanistic explanation for this phenomenon. While Pütter’s growth model was indirectly influential through its adaptation by Ludwig von Bertalanffy (1901–1972), his explanation of the influence of temperature on growth remained either unknown or misunderstood. In this contribution, we reconstruct the theoretical framework of his model and compare it to recent critiques of mechanistic models on growth and temperature. As we argue, Pütter’s theory of “similarities of growth” provides explanations for observed temperature–size patterns trends that avoid later accounts of underlying “biological laws.” While recent findings suggest that some aspects of Pütter’s model need revision—for example, the proposed exponents of the anabolic and catabolic terms in his growth equation—we argue that his mechanistic model was designed in a way that could account for the multiple apparent exceptions to the temperature–size rule that were recently found.

The evolution of biparental sexual reproduction in animals and plants is a prominent focus in modern biology. One hundred and fifty years ago, the German biologist Julius Sachs (1832–1897) published the fourth and final edition of his influential Textbook of Botany. In the text, he referred to the work of Wilhelm Hofmeister (1824–1877) and proposed that it is possible to reconstruct the origins and evolution of sexuality via systematic comparisons among the life cycles of simple versus complex organisms. Sachs’s 1874 book presented the green alga Pandorina as an example of ancestral life cycles, and that of the land plants as the most complex photosynthetic organisms. Herein, we describe the 150-year-old hypothesis proposed by Sachs and show how the purported “architect of modern plant physiology” provided insights into (1) recent papers implicating the role of HMG-box genes for the expression of male versus female sex determination in complex eukaryotes, such as animals, brown algae, and fungi; and (2) the continuing debate about the meaning of homology in the context of evolution. We conclude that the physiologist Sachs, along with Hofmeister, was also one of the founders of comparative sex research in animals and plants.

AbstractThe Price equation provides a comprehensive representation of evolutionary processes. Since its original formulation by George Price, it has been used to model a variety of phenomena in quantitative genetics and related fields. However, there is no consensus on the explanatory power of the equation. In this article we aim to clarify its place within modern evolutionary theory. To this end, we first state the basic concepts from which the Price equation can be derived as a theorem. From this axiomatization, we conclude that the Price equation is not explanatory in itself. It merely provides a phenomenological description of evolutionary processes. We argue that its role is analogous to that of Galilean kinematics in classical mechanics. Both the Price equation and Galilean kinematics function as conceptual frameworks that define the basic features of the behavior of a class of systems. Practitioners are encouraged to theorize further on these frameworks to find the possible explanation of this behavior in various specific scenarios. Thus, despite its phenomenological character, the Price equation integrates different fields of evolutionary biology by providing a common formalization of their shared explanandum.

AbstractThis article defends a selective eliminativist position with respect to the concept of “biological lineage” as used in certain areas of contemporary evolutionary biology. We argue that its primary epistemic roles in these contexts—explaining social evolution and cumulative selection—clash with empirical evidence, and that enforcing the concept of “lineage” even obstructs fruitful research avenues in several biological research fields, including phylogenetic research. Drawing on this, we suggest that, in many instances, it would be best to get rid of the concept of “lineage” and think in terms that are more closely aligned with the empirical complexity of the biological world. Specifically, this entails that, instead of looking for the lineage that may have given rise to the entities possessing certain biological characteristics, biologists should generally look for any potential process allowing such possession, with the formation of a lineage just one possibility among many.

AbstractIn this article, I demonstrate two ways in which our major theories of the evolution of cooperation may fail to capture particular social phenomena. The first shortcoming of our current major theories stems from the possibility of mischaracterizing the cooperative problem in game theory. The second shortcoming of our current major theories is the insensitivity of these explanatory models to ecological and genomic context. As a case study to illustrate these points, I will use the cooperative interaction of a species of myxobacteria called Myxococcus xanthus. M. xanthus cooperate in many areas of their life cycle—in quorum sensing, social motility, fruiting body formation, and predation. I focus in particular on predation as we have not yet discovered an adequate explanation of how they sustain cooperative predation in the face of developmental cheats. In explaining why we have not, I draw generalizable conclusions that shed light on our use of simplified models to explain real-world behaviors in a variety of organisms.

AbstractThe roles played by physics in the study of the life sciences have taken many forms over the past 100 years. Here we analyze how physics can be brought to bear on the contemporary study of morphogenesis, where new tissue-scale forms arise out of simpler, more homogenous, initial structures. We characterize how morphogenesis has been studied through reductionist approaches and discuss their limitations. We suggest that an alternative way of approaching morphogenesis that begins with a consideration of the whole may also serve as a fruitful mode of scientific inquiry. Through historical analysis of concepts relevant for contemporary systems biology, we illustrate how physical thinking oriented toward the biological whole (“holistic biophysical thinking”) was exemplified in the biological theories presented earlier by D’Arcy Thompson (1860–1948) and Pere Alberch (1954–1998). We contrast the use of physics to develop the conceptual foundations of holistically oriented systems biology with the more prevalent contemporary use of physics that focuses on technological development and quantification, embedded within reductionist strategies. As an in-depth contemporary case study, we describe how in our research we have used holistic biophysical thinking to develop biological theories of vertebrate morphogenesis that account for and extend beyond genetic, molecular, and cellular processes. We propose a theory of skin development where both molecular and morphological patterns are orchestrated by emergent physical processes at the supracellular scale. We further posit that holistic biophysical thinking at the supracellular scale may advance theories of diseases such as cancer.

AbstractThough often presented as a recent scientific endeavor, synthetic biology began in the 19th century and was a particularly active field in the years preceding the publication of D’Arcy Thompson’s On Growth and Form. Much synthetic biology of the era was devoted to the construction of nonliving chemical systems that would undergo morphogenesis or dynamic behaviors which had been observed in living organisms. The point was to show that “life-like” structure and behavior could be generated by physicochemical laws and required no vitalist element. D’Arcy Thompson’s careful analysis of physicochemical morphogenetic mechanisms as possible explanations of organic form links closely to this way of thinking. In the modern era, when we can genetically engineer cells to undergo specific behaviors, and program cells to undergo simple morphogenetic behaviors of the kind that Thompson and others felt might underly natural morphogenesis, it is possible to test whether they will in fact produce a predictable multicellular shape. This addresses essentially the same questions about the morphogenetic role of physicochemical forces, such as surface tension, but does so “the other way round”: physicochemical mechanisms are not being used as models for morphogenesis by natural cells but rather as a means to engineer cells to make designed forms.