No full-text available
To read the full-text of this research,
you can request a copy directly from the authors.
The Miscellaneous Transitions in Evolution
Abstract
This chapter argues that John Maynard Smith and Eörs Szathmáry do not provide a coherent, well-motivated framework for thinking about the history of life. The chapter presents two projects that are very different, the first focusing on the Great Chain and the second on the history of life, ignoring the Great Chain. It also considers Ledyard Stebbins’ eight “major levels of organization” in evolution. These eight levels try to justify the Great Chain. This chapter may seem uncharitable, especially in its treatment of Maynard Smith and Szathmáry, whose work has been so well received.
... Since 1995, the MTE framework has been updated (79) and criticized (80), primarily on the grounds that Maynard Smith and Szathmáry's original list of eight major transitions lacked theoretical unity (28,48). For example, number eight on the original list (49,50), "primate societies to human societies (language)," fails to meet the criterion of previously free-living entities becoming integrated into higher-level individuals (28,(81)(82)(83). ...
... Since 1995, the MTE framework has been updated (79) and criticized (80), primarily on the grounds that Maynard Smith and Szathmáry's original list of eight major transitions lacked theoretical unity (28,48). For example, number eight on the original list (49,50), "primate societies to human societies (language)," fails to meet the criterion of previously free-living entities becoming integrated into higher-level individuals (28,(81)(82)(83). To achieve theoretical unity, the focus of the MTE framework has since shifted to the hierarchical (or nested) nature of biological organization (e.g., plants composed of cells, cells composed of organelles, etc.) (28,48,84), with the understanding that a 'major transition' constitutes "the emergence of a new population of evolutionary individuals" (48) (e.g., eukaryotes from bacteria and archaea). ...
... For example, number eight on the original list (49,50), "primate societies to human societies (language)," fails to meet the criterion of previously free-living entities becoming integrated into higher-level individuals (28,(81)(82)(83). To achieve theoretical unity, the focus of the MTE framework has since shifted to the hierarchical (or nested) nature of biological organization (e.g., plants composed of cells, cells composed of organelles, etc.) (28,48,84), with the understanding that a 'major transition' constitutes "the emergence of a new population of evolutionary individuals" (48) (e.g., eukaryotes from bacteria and archaea). Applying these criteria (Table 2), many MTE -such as the evolution of eusociality in naked mole-rats, or the evolution of coloniality in the Portuguese man o' war -are irrelevant to human origins (48). ...
According to the "hard-steps" model, the origin of humanity required "successful passage through a number of intermediate steps" (so-called "hard" or "critical" steps) that were intrinsically improbable with respect to the total time available for biological evolution on Earth. This model similarly predicts that technological life analogous to human life on Earth is "exceedingly rare" in the universe. Here, we critically reevaluate the core assumptions of the hard-steps model in light of recent advances in the Earth and life sciences. Specifically, we advance a potential alternative model where there are no hard steps, and evolutionary novelties (or singularities) required for human origins can be explained via mechanisms outside of intrinsic improbability. Furthermore, if Earth's surface environment was initially inhospitable not only to human life, but also to certain key intermediate steps in human evolution (e.g., the origin of eukaryotic cells, multicellular animals), then the "delay" in the appearance of humans can be best explained through the sequential opening of new global environmental windows of habitability over Earth history, with humanity arising relatively quickly once the right conditions were established. In this co-evolutionary (or geobiological) scenario, humans did not evolve "early" or "late" with respect to the total lifespan of the biosphere, but "on time."
... The reason, in a nutshell, that the IAU couldn't leave well enough alone is that 25 the existing classification would have identified all of the trans-Neptunian Objects as 26 planets, and there was no way short of blatant gerrymandering to change the definition 27 to exclude them but include Pluto. So why not just include all of the Trans-Neptunian 28 Objects? ...
... [11] In their chapter in 137 The Major Transitions in Evolution Revisited, Daniel McShea and Carl Simpson argued 138 that Maynard Smith and Szathmáry's list of major transitions lacks theoretical unity 139 and needs to be revised. [26] Michod, in the same volume, defended his shorter list of 140 transitions in individuality on the grounds that, unlike Maynard Smith and Szathmáry's 141 list, his constituted a natural kind (a category whose members share fundamental 142 similarities). [9] More recently, O'Malley and Powell pointed out that both the original 143 and revised forms of the major transitions framework fail as natural kinds, shoehorning 144 in events that fail to meet any common set of criteria and failing to include some events 145 that do. ...
... [9,25,27] Similarly, 174 the origin of language has been largely absent from discussions of major transitions, 175 and several authors have argued that it should be excluded for the sake of theoretical 176 consistency. [9,[25][26][27] Neither innovation meets what Maynard Smith and Szathmáry 177 themselves identify as their most important criterion, the shift from independent to 178 group replication. [4] Two of these things are not like the others; let us follow the IAU's 179 example and excise that which does not belong. ...
The ‘Major Transitions in Evolution’ (MTE) framework has emerged as the dominant paradigm for understanding the origins of life's hierarchical organization, but it has been criticized on the grounds that it lacks theoretical unity, that is, that the events included in the framework do not constitute a coherent category. I agree with this criticism, and I argue that the best response is to modify the framework so that the events it includes do comprise a coherent category, one whose members share fundamental similarities. Specifically, I recommend defining major transitions as all those, and only those, events and processes that result in the emergence of a new population of evolutionary individuals. Two sorts of change will be required to achieve this. First, events and processes that do not meet this criterion, such as the origins of the genetic code and of human language, should be excluded. Second, events and processes that do meet the criterion, but which have generally been neglected, should be included. These changes would have the dual benefits of making MTEs a philosophically coherent category and of increasing the sample size on which we may infer trends and general principles that may apply to all MTEs.
... For example, it is common to focus on the "complex" multicellular groups (Knoll 2011) to understand the evolution of multicellularity (Simpson 2011). But there are many other multicellular species and lineages (Bonner 2001;McShea 2001;Costa 2006;McShea and Simpson 2011;Herron et al. 2013;Niklas and Newman 2013) that do not possess germ-soma division of labor yet have much to teach, not just about multicellularity but also about how transitions occur. And engaging with these empirical examples should help untangle the conceptual issues around levels of selection, particularly when a new level of fitness is gained. ...
... The number of cell types in multicellular organisms and body types in colonial invertebrates is a convenient measure of the amount of adaptation that has taken place at the level of the group (Bell and Mooers 1997;McShea 2001;McShea and Changizi 2003;McShea and Simpson 2011;Simpson 2012). The majority of colonial animals possess only one body type (e.g., either polymorph types in bryozoans or caste types in eusocial insects), and the majority of multicellular organisms possess only one to seven cell types (Simpson 2012). ...
The fitness of groups is often considered to be the average fitness among constituent members. This assumption has been useful for developing models of multilevel selection, but its uncritical adoption has held back our understanding of how multilevel selection actually works in nature. If group fitness is only equal to mean member fitness, then it is a simple task to erode the importance of group-level selection in all multilevel scenarios—species selection could then be reduced to organismal selection as easily as group selection can. Because selection from different levels can act on a single trait, body size, for example, there must be a way to translate one level of fitness to another. This allows the calculation of the contributions of selection at each level. If high-level fitness is not a simple function of member fitness, then how do they interlace? Here we reintroduce Leigh Van Valen’s argument for the inclusion of expansion as a component of fitness. We show that expansion is an integral part of fitness even if one does not subscribe to the energetic view of fitness from which Van Valen originally derived it. From a hierarchical perspective, expansion is the projection of demographic fitness from one level to the next level up; differential births and deaths at one level produce differential expansion one level above. Including expansion in our conceptual tool kit helps allay concerns about our ability to identify the level of selection using a number of methods as well as allowing for the various forms of multilevel selection to be seen as manifestations of the same basic process.
... There is a some disagreement in the literature about what exactly counts as a major evolutionary transition, as a number of commentators have pointed out (Queller, 1997;McShea and Simpson, 2011;Herron, 2021). In their 1995 book, Maynard Smith and Szathmáry offered a 2-fold characterization of an MET. ...
... However, against Szathmáry, others have worried that the notion of a major transition has simply become too broad, sometimes seeming to include any evolutionary event that an author deems "important" enough by whatever yardstick they choose (McShea and Simpson, 2011). My own view is that an MET is best defined in terms of Maynard Smith and Szathmáry's second characterization, that is, as the evolution of a higherlevel biological unit out of formerly-free living units. ...
Over the last thirty years, the study of major evolutionary transitions has become a thriving research program within evolutionary biology. In addition to its obvious scientific interest, this research program raises interesting philosophical questions. These fall into two categories: conceptual and ontological. The former category includes questions about what exactly an evolutionary transition is, what form an evolutionary explanation of a transition should take, and whether a general theory that applies to all transitions is possible. The latter category includes questions about the status of the higher-level units to which evolutionary transitions give rise (e.g., organism, superorganism, or individual), and about the nature of the resulting hierarchical organization. Tackling these questions requires an integrative approach that draws on both biology and the philosophy of science.
... They argued that the long-term trend in complexity was the result of a series of changes in the way that information is stored and transmitted, known as the ''major transitions in evolution.'' Although this model has drawn some criticism for combining different types of evolutionary processes into the same category (such as the evolution of the genetic code together with the evolution of sex and the evolution of language; McShea and Simpson, 2011;O'Malley and Powell, 2016), the remaining transitions (the origin of cells and chromosomes from groups of interacting replicators, the origin of the eukaryotic cell, the evolution of multicellularity, and the evolution of eusociality) share the common feature that smaller entities evolve to become specialized parts of new, ''higher-level'' entities. This idea set the foundation for subsequent works focused on transitions that involve a shift in the hierarchical complexity of organisms, termed major evolutionary transitions in individuality (Herron, 2021). ...
All organisms living on Earth descended from a single, common ancestral population of cells, known as LUCA-the last universal common ancestor. Since its emergence, the diversity and complexity of life have increased dramatically. This chapter focuses on four key biological innovations throughout Earth's history that had a significant impact on the expansion of phylogenetic diversity, organismal complexity, and ecospace habitation. First is the emergence of the last universal common ancestor, LUCA, which laid the foundation for all life-forms on Earth. Second is the evolution of oxygenic photosynthesis, which resulted in global geochemical and biological transformations. Third is the appearance of a new type of cell-the eukaryotic cell-which led to the origin of a new domain of life and the basis for complex multicellularity. Fourth is the multiple independent origins of multicellularity, resulting in the emergence of a new level of complex individuality. A discussion of these four key events will improve our understanding of the intertwined history of our planet and its inhabitants and better inform the extent to which we can expect life at different degrees of diversity and complexity elsewhere.
... The list of proposed transitions also skews towards striking changes, particularly those that make humans unique. The risk of anthropocentrism looms [12]. It is unclear what principled grounds there might be for accepting any particular proposed transition. ...
The evolutionary history of animal cognition appears to involve a few major transitions: major changes that opened up new phylogenetic possibilities for cognition. Here, we review and contrast current transitional accounts of cognitive evolution. We discuss how an important feature of an evolutionary transition should be that it changes what is evolvable, so that the possible phenotypic spaces before and after a transition are different. We develop an account of cognitive evolution that focuses on how selection might act on the computational architecture of nervous systems. Selection for operational efficiency or robustness can drive changes in computational architecture that then make new types of cognition evolvable. We propose five major transitions in the evolution of animal nervous systems. Each of these gave rise to a different type of computational architecture that changed the evolvability of a lineage and allowed the evolution of new cognitive capacities. Transitional accounts have value in that they allow a big-picture perspective of macroevolution by focusing on changes that have had major consequences. For cognitive evolution, however, we argue it is most useful to focus on evolutionary changes to the nervous system that changed what is evolvable, rather than to focus on specific cognitive capacities.
... Waring and Wood's (2021) arguments interpret the major transitions framework in a particularly strong way. This takes transitions to involve stabilizing a new evolutionary individual, here a cultural group (McShea & Simpson, 2011). But one need not understand the framework in this "unified" way (Michod, 1999). ...
The goal of Artificial Life research, as articulated by Chris Langton, is "to contribute to theoretical biology by locating life-as-we-know-it within the larger picture of life-as-it-could-be." The study and pursuit of open-ended evolution in artificial evolutionary systems exemplify this goal. However, open-ended evolution research is hampered by two fundamental issues: the struggle to replicate open-endedness in an artificial evolutionary system and our assumption that we only have one system (genetic evolution) from which to draw inspiration. We argue not only that cultural evolution should be seen as another real-world example of an open-ended evolutionary system but that the unique qualities seen in cultural evolution provide us with a new perspective from which we can assess the fundamental properties of, and ask new questions about, open-ended evolutionary systems, especially with regard to evolved open-endedness and transitions from bounded to unbounded evolution. Here we provide an overview of culture as an evolutionary system, highlight the interesting case of human cultural evolution as an open-ended evolutionary system, and contextualize cultural evolution by developing a new framework of (evolved) open-ended evolution. We go on to provide a set of new questions that can be asked once we consider cultural evolution within the framework of open-ended evolution and introduce new insights that we may be able to gain about evolved open-endedness as a result of asking these questions.
... The same can be said for social systems, including those of humans (cf. [6], 30). Simulations of cultural evolutionary dynamics suggest that cultural traits may emerge and persist in small populations for long time spans [7]. ...
Great transitions are thought to embody major shifts in locus of selection, labour diversification and communication systems. Such expectations are relevant for biological and cultural systems as decades of research has demonstrated similar dynamics within the evolution of culture. The evolution of the Neo-Inuit cultural tradition in the Bering Strait provides an ideal context for examination of cultural transitions. The Okvik/Old Bering Sea (Okvik/OBS) culture of Bering Strait is the first representative of the Neo-Inuit tradition. Archaeological evidence drawn for settlement and subsistence data, technological traditions and mortuary contexts suggests that Okvik/OBS fits the definition of a major transition given change in the nature of group membership (from families to political groups with social ranking), task organization (emergent labour specialization) and communication (advent of complex art forms conveying social and ideological information). This permits us to develop a number of implications about the evolutionary process recognizing that transitions may occur on three scales: (1) ephemeral variants, as for example, simple technological entities; (2) integrated systems, spanning modular technology to socio-economic strategies; and (3) simultaneous change across all scales with emergent properties.
This article is part of the theme issue ‘Human socio-cultural evolution in light of evolutionary transitions’.
... They are transitions in which a new higher-level individual emerged or there was a change in the way information was transmitted from one generation to the next. The concern here is only with individuality [42,43]. ...
The ‘major transitions in evolution’ are mainly about the rise of hierarchy, new individuals arising at ever higher levels of nestedness, in particular the eukaryotic cell arising from prokaryotes, multicellular individuals from solitary protists and individuated societies from multicellular individuals. Some lists include human societies as a major transition, but based on a comparison with the non-human transitions, there are reasons for scepticism. (i) The foundation of the major transitions is hierarchy, but the cross-cutting interactions in human societies undermine hierarchical structure. (ii) Natural selection operates in three modes—stability, growth and reproductive success—and only the third produces the complex adaptations seen in fully individuated higher levels. But human societies probably evolve mainly in the stability and growth modes. (iii) Highly individuated entities are marked by division of labour and commitment to morphological differentiation, but in humans differentiation is mostly behavioural and mostly reversible. (iv) As higher-level individuals arise, selection drains complexity, drains parts, from lower-level individuals. But there is little evidence of a drain in humans. In sum, a comparison with the other transitions gives reasons to doubt that human social individuation has proceeded very far, or if it has, to doubt that it is a transition of the same sort.
This article is part of the theme issue ‘Human socio-cultural evolution in light of evolutionary transitions’.
... Although targeted to digital evolution use cases, impact of our work extends beyond to the various applications of digital evolution. Evolutionary biology poses uniquely abstract, nuanced, and nebulous questions, such as the origins of life and the evolution of complexity (McShea & Simpson, 2011;Pross, 2016). Computational modeling provides one foothold for such inquiry, particularly with respect to phenomena that typically unfold on geological timescales or hypotheses that invoke counterfactuals outside the bounds of physical reality (Clune et al., 2011;McKinley et al., 2008;O'Neill, 2003). ...
... Barron, Halina, and Klein (draft ms) suggest that transitions might be understood in terms of changes in information flow in nervous systems, positing centralization, recurrence, and lamination as key major transitions. McShea and Simpson (2011) note that while changes in information flow are part of Smith and Szathmáry's discussion, they remain under-theorized and likely more important as organisms become more complex. brains the question is relatively pressing, as it seems that even very simple brains possess considerable computational power. ...
One challenge in explaining neural evolution is the formal equivalence of different computational architectures. If a simple architecture suffices, why should more complex neural architectures evolve? The answer must involve the intense competition for resources under which brains operate. I show how recurrent neural networks can be favored when increased complexity allows for more efficient use of existing resources. While resource constraints alone can drive a change, recurrence shifts the landscape of what is later evolvable. Hence organisms on either side of a transition boundary may have similar cognitive capacities, but very different potential for evolving new capacities.
... Within this history, Maynard defined Major Evolutionary Transitions (METs) as leaps in organismal complexity forming higherlevel 'individuals' or creating novel forms of information storage or transfer, regardless of any resulting ecosystem impacts (Szathmáry, 2015). Analogously, we classify as Major Competitive Transitions (MCTs) biological innovations that produced significant direct-fitness advantages within lineages, such as shelled eggs or endothermy (Huxley, 1942;McShea and Simpson, 2011), regardless of their broader ecosystem impacts. ...
A small number of extraordinary “Major Evolutionary Transitions” (METs) have attracted attention among biologists. They comprise novel forms of individuality and information, and are defined in relation to organismal complexity, irrespective of broader ecosystem-level effects. This divorce between evolutionary and ecological consequences qualifies unicellular eukaryotes, for example, as a MET although they alone failed to significantly alter ecosystems. Additionally, this definition excludes revolutionary innovations not fitting into either MET type (e.g., photosynthesis). We recombine evolution with ecology to explore how and why entire ecosystems were newly created or radically altered – as Major System Transitions (MSTs). In doing so, we highlight important morphological adaptations that spread through populations because of their immediate, direct-fitness advantages for individuals. These are Major Competitive Transitions, or MCTs. We argue that often multiple METs and MCTs must be present to produce MSTs. For example, sexually-reproducing, multicellular eukaryotes (METs) with anisogamy and exoskeletons (MCTs) significantly altered ecosystems during the Cambrian. Therefore, we introduce the concepts of Facilitating Evolutionary Transitions (FETs) and Catalysts as key events or agents that are insufficient themselves to set a MST into motion, but are essential parts of synergies that do. We further elucidate the role of information in MSTs as transitions across five levels: (I) Encoded; (II) Epigenomic; (III) Learned; (IV) Inscribed; and (V) Dark Information. The latter is ‘authored’ by abiotic entities rather than biological organisms. Level IV has arguably allowed humans to produce a MST, and V perhaps makes us a FET for a future transition that melds biotic and abiotic life into one entity. Understanding the interactive processes involved in past major transitions will illuminate both current events and the surprising possibilities that abiotically-created information may produce.
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
Am Anfang dieses Buches haben wir die Idee des großen Filters vorgestellt, etwas, das zwischen der Entstehung von Planeten (vom dem wir wissen, dass es oft passiert) und der Existenz technologischer Zivilisationen (die selten zu sein scheinen) steht. Wir haben uns gefragt, was dieser große Filter wohl sein könnte, und vermutet, dass es sich im Laufe der rund 4 Mrd. Jahre um jeden der vielen Schritte handeln könnte, die vom Ursprung des Lebens zur modernen Menschheit geführt haben.
... Under the theory of natural selection, which assumes a single deterministic force, the broad-scale course of evolution proceeds as repeated bouts of phyletic microevolution (Fig. 6). The necessary implication is that, even if evolution is a history of key innovations [105], the broad-scale course of evolution is one arbitrary thing after another [121]. The theory of natural reward, in contrast, provides a connection between microevolution and macroevolution by viewing natural selection as a creative process that produces complex inventions that are the fodder for the struggle for supremacy (Fig. 6). ...
Darwin's theory of evolution by natural selection does not predict long-term progress or advancement, nor does it provide a useful way to define or understand these concepts. Nevertheless, the history of life is marked by major trends that appear progressive, and seemingly more advanced forms of life have appeared. To reconcile theory and fact, evolutionists have proposed novel theories that extend natural selection to levels and time frames not justified by the original structure of Darwin's theory. To extend evolutionary theory without violating the most basic tenets of Darwinism, I here identify a separate struggle and an alternative evolutionary force. Owing to the abundant free energy in our universe, there is a struggle for supremacy that naturally rewards those that are first to invent novelties that allow exploitation of untapped resources. This natural reward comes in form of a temporary monopoly, which is granted to those who win a competitive race to innovate. By analogy to human economies, natural selection plays the role of nature's inventor, gradually fashioning inventions to the situation at hand, while natural reward plays the role of nature's entrepreneur, choosing which inventions to first disseminate to large markets. Natural reward leads to progress through a process of invention-conquest macroevolution, in which the dual forces of natural selection and natural reward create and disseminate major innovations. Over vast time frames, natural reward drives the advancement of life by a process of extinction-replacement megaevolution that releases constraints on progress and increases the innovativeness of life.
... Maynard-Smith and Szathmary's work has provided much fodder for philosophers and theoretically-inclined scientists. Common questions concern the unity or otherwise of major transitions (McShea and Simpson 2011;O'Malley and Powell 2016), characterizing the kind of explanations involved (Calcott and Sterelny 2011), and so on. These discussions will matter later, but for now let's consider what evidence might be relevant to understanding major transitions. ...
Both paleobiology and investigations of ‘major evolutionary transitions’ are intimately concerned with the macroevolutionary shape of life. It is surprising, then, how little studies of major transitions are informed by paleontological perspectives and. I argue that this disconnect is partially justified because paleobiological investigation is typically ‘phenomena-led’, while investigations of major transitions (at least as commonly understood) are ‘theory-led’. The distinction turns on evidential relevance: in the former case, evidence is relevant in virtue of its relationship to some phenomena or hypotheses concerning those phenomena; in the latter, evidence is relevant in virtue of providing insights into, or tests of, an abstract body of theory. Because paleobiological data is by-and-large irrelevant to the theory which underwrites the traditional conception of major transitions, it is of limited use to that research program. I suggest that although the traditional conception of major transitions is neither ad-hoc or problematically incomplete, its promise of providing unificatory explanations of the transitions is unlikely to be kept. Further, examining paleobiological investigations of mass extinctions and organogenesis, I further argue that (1) whether or not transitions in paleobiology count as ‘major’ turns on how we conceive of major transitions (that is, the notion is sensitive to investigative context); (2) although major transitions potentially have a unified theoretical basis, recent developments suggest that investigations are becoming increasingly phenomena-led; (3) adopting phenomena-led investigations maximizes the evidence available to paleobiologists.
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
Upcoming telescopes might be able to detect signatures of complex life on other worlds, but we need to involve physical, chemical and life scientists at the planning stage in order to interpret the findings when the time comes.
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
Sophisticated life forms will prove to be remarkably common in the universe, say Dirk Schulze-Makuch and William Bains
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
The most monumental event in life’s history on our planet is its origin. Many early scientists, trying to understand the phenomenon of life, thought that ‘dead’ matter and energy alone cannot explain life, and that there must be a vital essence in living organisms that distinguishes them from the non-living world. Our current understanding refutes this, and shows that life is a chemical system, and follows the same rules as any other chemistry. The chemistry of life is extraordinarily complicated and intricate, but it is still chemistry. So some time that living chemistry must have arisen from the non-living chemistry of its environment. However, despite nearly 150 years of modern science since Darwin speculated on life’s appearance in ‘some warm little pond’ in his letter to J. D. Hooker on 1 February 1871, we still do not know how life originated on Earth.
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
The prokaryotic world is composed of the domains Archaea and Bacteria (Box 1.1), which dominate our planet based on their sheer numbers. However, in the evolution of increasing complexity, the emergence of another major type of cell, the eukaryotic cell, was a critical innovation. While many eukaryotes are single-celled organisms, as are bacteria, some eukaryotes form multicellular lifeforms, in which cells form a larger organism that is much more than a collection of its parts (see Chap. 8 for more on multicellularity). Prokaryotes do not do this (although they can band together in simpler ways). Even single celled eukaryotes such as the protozoa can have extremely complex structures within a single cell, as exemplified by unicellular organisms such as Paramecium (Fig. 6.1). So how eukaryotes arose is central to our understanding of how complex life appeared on Earth.
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
So far in this book we have argued, we hope persuasively, that many things possessed by complex organisms such as ourselves—eukaryotic cells, multicellularity, sex—and things we depend on, such as oxygen, were likely outcomes once life was established on Earth 3.5 billion years ago. But we have scarcely mentioned the appearance of large organisms themselves. What about molluscs and dinosaurs and trees?
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
Are humans a galactic oddity, or will complex life with human abilities develop on planets with environments that remain habitable for long enough? In a clear, jargon-free style, two leading researchers in the burgeoning field of astrobiology critically examine the major evolutionary steps that led us from the distant origins of life to the technologically advanced species we are today.
Are the key events that took life from simple cells to astronauts unique occurrences that would be unlikely to occur on other planets? By focusing on what life does - it's functional abilities - rather than specific biochemistry or anatomy, the authors provide plausible answers to this question. Systematically exploring the various pathways that led to the complex biosphere we experience on planet Earth, they show that most of the steps along that path are likely to occur on any world hosting life, with only two exceptions: One is the origin of life itself – if this is a highly improbable event, then we live in a rather “empty universe”. However, if this isn’t the case, we inevitably live in a universe containing a myriad of planets hosting complex as well as microbial life - a “cosmic zoo”. The other unknown is the rise of technologically advanced beings, as exemplified on Earth by humans. Only one technological species has emerged in the roughly 4 billion years life has existed on Earth, and we don’t know of any other technological species elsewhere. If technological intelligence is a rare, almost unique feature of Earth's history, then there can be no visitors to the cosmic zoo other than ourselves.
Schulze-Makuch and Bains take the reader through the history of life on Earth, laying out a consistent and straightforward framework for understanding why we should think that advanced, complex life exists on planets other than Earth. They provide a unique perspective on the question that puzzled the human species for centuries: are we alone?
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
When life started it was likely powered by chemical reactions between chemicals—primarily rocks and gases—that were already present in the early Earth environment. If life originated at hydrothermal vents deep in the sea (as we think is a distinct possibility, as discussed in the last chapter), the volcanic rocks and the gases from volcanic exhalations, such as carbon dioxide and hydrogen gas, reacted to produce methane and water. Some microorganisms still use this as a source of energy today, and the enzymes that they use for this chemistry appear to be extremely ancient. However, this is a very limited source of energy. There are only a few places on Earth where the crust provides energy for life. Reduced rocks that could react with gases are rare, as they can react on their own (albeit slowly), especially with atmospheric gases. Hydrogen is produced in hydrothermal systems like geysers and sea-floor vents, but these occupy only a tiny fraction of the Earth’s surface. Other places where geological energy abounds, such as volcanoes, are so extreme that life cannot survive there. So life can start in such places, but could never spread.
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
In the beginning of this book we introduced the idea of a Great Filter, something that stood between the formation of planets (which we know is common) and the existence of technological civilizations (which seems rare). We asked ourselves where the Great Filter may be and surmised that it may be located in principle at any of the many steps that have led from the origin of life to modern humanity over a time period of roughly 4 billion years.
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
All life is made up of cells. Unicellular organisms, as the name suggests, have just one cell, although that cell can be enormously complex. Multicellular organisms contain not just many cells, but critically they contain cells that are different from each other. Originating from a single egg, they develop into different cell types that have different functions. It is this specialization that allows multicellular organisms to develop complex structures such as leaves, eyes and brains. Hence the definition of a multicellular organism put forward by G. Bell and A. Mooers in 1997, that multicellular organisms are clones of cells that express different phenotypes despite having the same genotype. The ‘phenotype’ is the physical characteristics of a cell or an organism that the genes program. For example, in humans, liver and brain and muscle cells all have the same set of genes and all derive from one fertilised egg cell, but they are clearly extremely different. This definition captures the most distinctive property of multicellular organisms. Differentiation and eventually specialization within a group of cells with the same genome leads to the increased complexity that we attribute to multicellular organisms. While all the cells of an individual organism have the same genomes, different sets of those genes are active in different cells within the organism. The only clarification which we might want to add to the pointedly short definition by Bell and Mooers is that this achieved differentiation has to be of a cooperative rather than a competitive nature.
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
Before we start to discuss how life evolves on a planet, we have to address whether a planet can support life even in principle. The minimum requirements are at a higher bar for complex life than for microbial life. We will start our discussion by reviewing what makes Earth a habitable planet, and how our planetary history is closely interwoven with the rise and persistence of life, in stark contrast to our neighboring planets which seem rather inhospitable. Then we discuss the astronomical and planetary constraints on habitability and life, particularly complex life, and speculate whether the preconditions for life are common in the Universe.
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
Humans, or at least the humans reading this book, pride themselves on their intelligence. Humans have by far the most advanced material culture and sophisticated, flexible communication system of any creature on Earth. But many animals show accomplishments that suggest substantial intelligence. So what is intelligence, and how likely is it to arise?
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
Oxygen in the air is essential for animal life, especially our own. A healthy adult human can go 2 weeks or more without food, several days without water, but no more than 5 minute without oxygen before he or she suffers irreversible damage. Every schoolchild knows that green plants use the energy of sunlight to make the oxygen that we breath. The making of oxygen, a process called oxygenesis, is seen as being of central importance to the development of complex life. Without oxygen, none of today’s complex animals could survive, from corals to camels. Donald Canfield says that “The evolution of oxygen-producing cyanobacteria was arguably the most significant event in the history of life after the evolution of life itself”. And yet in the last chapter we did not mention oxygen at all. Why?
... в современном контексте -это соразмерность частей, слияние различных компонентов объектов в единое органическое целое. Следуя сущности указанного понятия, можно предположить, что цели инвестиционно-строительной деятельности должны быть соизмерены и соотнесены не только между собой, но и с затратами, которые также должны находиться в ограниченном взаимосоответствии [1,2]. Это необходимо вследствие того, что, следуя логике гармоничного подхода, доминирование одного вида затрат изначально приведет к возникновению проблем развития, противостоянию категорий работников, дискриминации, возникновению противоречий, а также конфликту интересов. ...
The management of construction companies’ development is rarely aimed at harmonization of business and at the development of the ways of its sustainable development. Case studies and the application scope for harmonization as an approach allowing systematic and balanced development of business showed its practical relevance. The use of this approach allows not only correlating the objectives, clarifying the mission, structuring the problems, or determining the optimal salary of employees, but also correlating the costs to each other, which is particularly important in light of the need for rapid transformation of the building production methods. They are based on competent use of system properties of the systems. The properties of emergence, resonance, measurability, and others are of particular importance. Their accounting allows achieving the optimal cost outlay required in the process of investment and construction activities. It complies with the requirements and conditions of the market economy. The mentioned advantages of the use of harmonization technologies to ensure the stability and sustainability of investment and construction activities enable to confirm the hypothesis of the impossibility to achieve the optimum cost, for example, for the implementation of an investment and construction project without implementation of the system properties of a harmonious approach.
... DACtoc proposes that nervous systems facilitated the formation of social groups, in particular, through the emergence of primary and secondary consciousness. Evolutionary progress has been sketched as enhanced autonomy from the environment (see [212] for a review). The DACtoc hypothesis suggests, however, that we might have to consider a tertiary consciousness that is unique to humans, allowing them to redefine their value systems on the basis of socially acquired norms implemented by the feedback control of the neocortex over the norm systems of the CBS and its intentionality prior. ...
Understanding the nature of consciousness is one of the grand outstanding scientific challenges. The fundamental methodological problem is how phenomenal first person experience can be accounted for in a third person verifiable form, while the conceptual challenge is to both define its function and physical realization. The distributed adaptive control theory of consciousness (DACtoc) proposes answers to these three challenges. The methodological challenge is answered relative to the hard problem and DACtoc proposes that it can be addressed using a convergent synthetic methodology using the analysis of synthetic biologically grounded agents, or quale parsing. DACtoc hypothesizes that consciousness in both its primary and secondary forms serves the ability to deal with the hidden states of the world and emerged during the Cambrian period, affording stable multi-agent environments to emerge. The process of consciousness is an autonomous virtualization memory, which serializes and unifies the parallel and subconscious simulations of the hidden states of the world that are largely due to other agents and the self with the objective to extract norms. These norms are in turn projected as value onto the parallel simulation and control systems that are driving action. This functional hypothesis is mapped onto the brainstem, midbrain and the thalamo-cortical and cortico-cortical systems and analysed with respect to our understanding of deficits of consciousness. Subsequently, some of the implications and predictions of DACtoc are outlined, in particular, the prediction that normative bootstrapping of conscious agents is predicated on an intentionality prior. In the view advanced here, human consciousness constitutes the ultimate evolutionary transition by allowing agents to become autonomous with respect to their evolutionary priors leading to a post-biological Anthropocene.
This article is part of the themed issue ‘The major synthetic evolutionary transitions’.
... In this paper, we analyse the transitions or key innovations within a theoretical framework that allows us to ask whether the evolution of a technology-using species on Earth is an extremely unlikely event, or whether complex, smart and potentially technological beings are highly likely to evolve on an habitable planet in the time available to it (10 Gigayears (Ga) in the case of the Earth orbiting around our Sun). This is a highly anthropocentric approach, but we take it deliberately because we are interested in the evolution of complex and intelligent organisms such as ourselves (McShea and Simpson [2]). No evidence of technologically advanced life other than human life has been found, which suggests that such technologically advanced life occurs only on a minor fraction of all habitable planets. ...
Life on Earth provides a unique biological record from single-cell microbes to technologically intelligent life forms. Our evolution is marked by several major steps or innovations along a path of increasing complexity from microbes to space-faring humans. Here we identify various major key innovations, and use an analytical toolset consisting of a set of models to analyse how likely each key innovation is to occur. Our conclusion is that once the origin of life is accomplished, most of the key innovations can occur rather readily. The conclusion for other worlds is that if the origin of life can occur rather easily, we should live in a cosmic zoo, as the innovations necessary to lead to complex life will occur with high probability given sufficient time and habitat. On the other hand, if the origin of life is rare, then we might live in a rather empty universe.
... Is there theoretical unity, or just a "series of miscellaneous transitions"? (McShea & Simpson, 2011). The latter part of this paper shows that we can say something systematic about (at least some such) evolutionary transitions by harnessing a second-order generalization governing certain probabilistic evolutionary processes. ...
There is a worry that the 'major transitions in evolution' represent an arbitrary group of events. This worry is warranted, and we show why. We argue that the transition to a new level of hierarchy necessarily involves a nonselectionist chance process. Thus any unified theory of evolutionary transitions must be more like a general theory of fortuitous luck, rather than a rigid formulation of expected events. We provide a systematic account of evolutionary transitions based on a second-order regularity of chance events, as stipulated by the ZFEL (Zero Force Evolutionary Law). And in doing so, we make evolutionary transitions explainable and predictable, and so not entirely contingent after all.
Copyright © 2014 Elsevier Ltd. All rights reserved.
When behaviors assemble into combinations, then synergies have a central role in the discovery of productive patterns of behavior. In our view—what we call the Synergy Emergence Principle (SEP)—synergies are dynamic attractors, drawing interactions toward greater returns as they happen, in the moment. This Principle offers an alternative to the two conventionally acknowledged routes to discovery: directed problem solving, involving forethought and planning; and the complete randomness of trial and error. Natural selection has a role in the process, in humans favoring the maintenance and improvement of certain key underlying capabilities, such as prosocial helping and episodic foresight, but selection is not required for discovery by synergy (which occurs too rapidly for selection anyway). Here we discuss the consequences of the SEP for the evolution in humans of key synergies such as tool usage and interactions that reward cooperation, show how discovery by synergy and the selection of synergy-supporting abilities formed a positive feedback loop, and show how synergies can combine, forming clusters and packages that are the core of institutions and cultures. Finally, clusters and packages represent an intermediate level of organization above the individual and below whole society, with consequences for our understanding of the major transitions in evolution.
I argue that an explicit distinction between cognitive characters and cognitive phenotypes is needed for empirical progress in the cognitive sciences and their integration with evolution-guided sciences. I elaborate what ontological commitment to characters involves and how such a commitment would clarify ongoing debates about the relations between human and nonhuman cognition and the extent of cognitive abilities across biological species. I use theoretical proposals in episodic memory, language, and sociocultural bases of cognition to illustrate how cognitive characters are being introduced in scientific practice.
Eörs Szathmáry and John Maynard Smith famously argued that the evolution of life on earth has been marked by a series of transitions to greater complexity, the last being from primate to human societies. I argue that this last transition, covering all of human evolutionary history, in turn comprises two phases: the first defined by increases in the capacity of the human brain/mind to structurally integrate causal inferences and selectively apply them to construct increasingly sophisticated sociocultural niches; the second defined by manipulation of the universal Darwinian mechanisms driving sociocultural evolution. During the first phase, hominin cognitive structure passed through three key transitions to produce the brain/mind of archaic Homo sapiens. The fourth transition, to fully modern Homo sapiens sapiens equipped with symbolic cognition and language, marks the fulcrum that leveraged the second phase in which changes in the scope and rate of niche construction were primarily driven by manipulation of sociocultural evolutionary mechanisms. The fifth transition to sedentary living enabled new selection pressures to be exerted through the concentration and application of social power, while the sixth transition multiplied the cognitive variation available to construct more elaborate sociocultural niches. Finally I note that decreasing intervals between transitions creates a pattern of accelerating sociocultural change.
Throughout the history of life on earth, rare and complex innovations have periodically increased the efficiency with which abiotic free energy and biotic resources are converted to biomass and organismal diversity. Such macroevolutionary expansions have increased the total amount of abiotic free energy utilized by life and shaped the earth's ecosystems. Meanwhile, Darwin's theory of natural selection assumes a historical, worldwide state of effective resource limitation, which could not possibly be true if life evolved from one or a few original ancestors. In this paper, I analyze the self-contradiction in Darwin's theory that comes from viewing the world and universe as effectively resource limited. I then extend evolutionary theory to include a second deterministic evolutionary force, natural reward. Natural reward operates on complex inventions produced by natural selection and is analogous to the reward for innovation in human economic systems. I hypothesize that natural reward, when combined with climate change and extinction, leads to the increased innovativeness, or what I call the advancement, of life with time. I then discuss applications of the theory of natural reward to the evolution of evolvability, the apparent sudden appearance of new forms in the fossil record, and human economic evolution. I conclude that the theory of natural reward holds promise as an explanation for the historical advancement of life on earth.
Many processes can contribute to macroevolutionary change. This fact is the source of the wide variety of macroevolutionary change across time and taxa as well as the bane of pale-obiological research trying to understand how macroevolution works. Here, I present a general framework for understanding the variety of macroevolutionary phenomena. Based on Price’s theorem, this framework provides a simple quantitative means to understand (1) the macroevolutionary processes that are possible and (2) the way those processes interact with each other. The major qualitative features of macroevolution depend first on the number of processes that co-occur and then on the magnitudes and evolutionary directions of those processes. Species selection, the major macroevolutionary process, consists of patterns of differential rates of speciation and extinction. Its macroevolutionary efficacy depends on the presences of sufficient microevolutionary change. Conversely, microevolutionary change is limited in power by the independent evolution of species, and species selection acting across populations of species can amplify or suppress microevolution. Non-trends may result if species selection sufficiently neutralizes microevolution and may yield stable macroevolutionary patterns over many millions of years.
Identifying and theorizing major turning points in the history of life generates insights into not only world‐changing evolutionary events but also the processes that bring these events about. In his treatment of these issues, Bonner identifies the evolution of sex, multicellularity, and nervous systems as enabling the “evolution of evolution,” which involves fundamental transformations in how evolution occurs. By contextualizing his framework within two decades of theorizing about major transitions in evolution, we identify some basic problems that Bonner's theory shares with much of the prevailing literature. These problems include implicit progressivism, theoretical disunity, and a limited ability to explain major evolutionary transformations. We go on to identify events and processes that are neglected by existing views. In contrast with the “vertical” focus on replication, hierarchy, and morphology that preoccupies most of the literature on major transitions, we propose a “horizontal” dimension in which metabolism and microbial innovations play a central explanatory role in understanding the broad‐scale organization of life.
Research highlights
• Accounts of major transitions are progressivist, disunified, and focused on vertical complexity, such as nestedness, bodies, and brains.
• Horizontal features such as metabolic and microbial processes are also crucial to the organization of life.
Morphological and functional hierarchies occurring in contemporary biological entities are amalgamated via a small number of progressive key-steps termed as Major Transition in Evolution (MTE) that encompass steps of Major Transition in Individuality (MTI). Literature views MTE/MTI in nature as a sequential increase in complexity, and has contributed insights into the emergence of genuine MTI candidates that actually build higher order individuals from simpler entities and into their specific properties. The theory- By considering a novel MTI trajectory termed the ‘MTI continuum’ (independent of the tree of life that contemplates taxonomic correlations), I found no literature consensus for this continuum’s apex. Next, I consider the properties of biological entities termed as ‘superorganism’ (eusocial insects, humans), also considered as highly-developed MTIs. I classify ‘superorganism’ as being on the level of ‘miscellaneous transitions’ that have not yet developed into real MTIs and that do not meet the ‘individual’ physiognomy. Then I assign the emergence of three new MTI diachronic-classes, the colonial-organisms, chimerism and multi-chimerism, suggesting that they represent highly complex MTIs that belong at the apex of the MTI continuum. These novel MTIs are neither fraternal, nor egalitarian, deprived of ‘kinship’ and ‘fairness’ considerations, yet still generate genuine and distinct libertarian entities. I posit that these MTIs embody the qualities of real units of selection.
The increasing maximal hierarchical complexity of organisms is one of the best-supported macroevolutionary trends. The nature and causes of this trend, as well as several accompanying macroevolutionary phenomena are, however, still unclear. In this theoretical article, we propose that the cause of this trend could be the increasing pressure of species selection, which results from the gradual decrease of (macro)evolutionary potential (i.e. the probability of producing major evolutionary innovations). As follows from the Theory of Frozen Evolution, this process is an inevitable consequence of the sorting of genes, traits, and their integrated groups (modules) based on their contextually dependent stability. In turn, this causes effectively unchangeable elements of genetic architecture to accumulate during the existence of evolutionary lineages. Although (macro)evolutionary potential can be partially restored by several processes, a profound restoration of (macro)evolutionary potential is probably possible only by means of a transition to a higher level of hierarchical complexity. However, the accumulation of contextually more stable elements continues even on this higher level. This leads to the integration of the modular character of composite organisms and a repeated pressure to increase the level of hierarchical complexity. Our model explains all components of McShea’s “Evolutionary Syndrome,” i.e. the trend of increasing the hierarchical complexity of organisms, the growth of variability among elements on the immediately lower level, and their gradual machinification. This pattern should be characteristic of sexual eukaryotes and especially their complex representatives. Our model also sheds new light on several related macroevolutionary phenomena, such as the gradual acceleration of the trend or the striking difference between pre-Neoproterozoic and Phanerozoic evolution.
Jared Diamond's argument against extraterrestrial intelligence from evolutionary contingency is subjected to critical scrutiny. As with the earlier arguments of George Gaylord Simpson, it contains critical loopholes that lead to its unraveling. From the point of view of the contemporary debates about biological evolution, perhaps the most contentious aspect of such arguments is their atemporal and gradualist usage of the space of all possible biological forms (morphospace). Such usage enables the translation of the adaptive value of a trait into the probability of its evolving. This procedure, it is argued, is dangerously misleading. Contra Diamond, there are reasons to believe that convergence not only plays an important role in the history of life, but also profoundly improves the prospects for search for extraterrestrial intelligence success. Some further considerations about the role of observation selection effects and our scaling of complexity in the great debate about contingency and convergence are given. Taken together, these considerations militate against the pessimism of Diamond's conclusion, and suggest that the search for traces and manifestations of extraterrestrial intelligences is far from forlorn. Key Words: Astrobiology-Evolution-Contingency-Convergence-Complex life-SETI-Major evolutionary transitions-Selection effects-Jared Diamond. Astrobiology 18, xxx-xxx.
Approaches to macroevolution require integration of its two fundamental components, i.e. the origin and the sorting of variation, in a hierarchical framework. Macroevolution occurs in multiple currencies that are only loosely correlated, notably taxonomic diversity, morphological disparity, and functional variety. The origin of variation within this conceptual framework is increasingly understood in developmental terms, with the semi-hierarchical structure of gene regulatory networks (GRNs, used here in a broad sense incorporating not just the genetic circuitry per se but the factors controlling the timing and location of gene expression and repression), the non-linear relation between magnitude of genetic change and the phenotypic results, the evolutionary potential of co-opting existing GRNs, and developmental responsiveness to nongenetic signals (i.e. epigenetics and plasticity), all requiring modification of standard microevolutionary models, and rendering difficult any simple definition of evolutionary novelty. The developmental factors underlying macroevolution create anisotropic probabilities—i.e., an uneven density distribution—of evolutionary change around any given phenotypic starting point, and the potential for coordinated changes among traits that can accommodate change via epigenetic mechanisms. From this standpoint, “punctuated equilibrium” and “phyletic gradualism” simply represent two cells in a matrix of evolutionary models of phenotypic change, and the origin of trends and evolutionary novelty are not simply functions of ecological opportunity. Over long timescales, contingency becomes especially important, and can be viewed in terms of macroevolutionary lags (the temporal separation between the origin of a trait or clade and subsequent diversification); such lags can arise by several mechanisms: as geological or phylogenetic artifacts, or when diversifications require synergistic interactions among traits, or between traits and external events. The temporal and spatial patterns of the origins of evolutionary novelties are a challenge to macroevolutionary theory; individual events can be described retrospectively, but a general model relating development, genetics, and ecology is needed. An accompanying paper (Jablonski in Evol Biol 2017) reviews diversity dynamics and the sorting of variation, with some general conclusions.
The Major Evolutionary Transitions theory of Szathmáry and Maynard Smith is famous for its contribution to the understanding of complex wholes in biology. Typical for Major Evolutionary Transitions theory is the select use of functional criteria, notably, cooperation, competition reduction and reproduction as part of a larger unit. When using such functional criteria, any group of attached cells can be viewed as multicellular, such as a plant or the slug-shaped aggregation of cells of a slime mould. In addition, one could also have used structural criteria to arrive at the conclusion that the cells in the slug of a slime mould are attached without plasma strands, while the cells of a plant are attached and connected through plasma strands. A theory which in addition to functional criteria also uses structural criteria for the identification of major transitions is the Operator Theory. Using the Operator Theory one can, for example, conclude that the slug of a slime mould represents a pluricellular organisation because its cells are not connected through plasma strands, while the cells of a plant are connected through plasma strands and for this reason represent a multicellular organism. In this chapter, the relationships between the Major Evolutionary Transitions theory and the Operator Theory are studied with a focus on transitions that lead to organisms.
Modern biology is ambivalent about the notion of evolutionary progress. Although most evolutionists understand large-scale macroevolution as a process that generated observable qualitative differences between organisms of different evolutionary levels, the term progress is usually avoided. The term carries some historical burden because it is problematic within the modern view of evolution, but at its core it expresses a central aspect of evolution that cannot be ignored if it is intended to build a fairly complete view of the evolutionary process coming close to reality.
The aim of this chapter is to give a definition of increasing biological autonomy. It is developed in two steps: In the first step, it is looked at biological autonomy in general, without taking changes into consideration. This step focuses on autonomy and robustness as a trait of living organisms. Here, it can be built on an extensive literature that provides a well-established notion of biological autonomy. In the second step, evolutionary changes in autonomy are inspected. There are also several forerunners of this, and some of them are presented with their respective approach and formulation. However, this literature did not generate a particular definition of changing or increasing autonomy; so finally a definition is presented that is used in the chapters to follow. This includes a list of components that are observed during evolutionary transitions. Both of these steps are developed within the framework of systems biology.
This chapter summarizes the different aspects of the theory of increasing autonomy in evolution. The relationship of autonomy to adaptation and natural selection is described, and questions for further research are identified. The evolutionary theories that are presently under discussion in the field are briefly outlined, and the contribution of the theory of autonomy to these new developments is considered.
In On the Origin of Autonomy; A New look at the Major Transitions in Evolution, Bernd Rosslenbroich argues that an increase of the relative autonomy of individual organisms is one of the central large-scale patterns in evolution. I begin by presenting how Rosslenbroich understands the notion of autonomy in biology and how he correlates its increase to different sets of morphological, physiological, and behavioral characteristics of various biological systems. I briefly discuss his view of directionality in evolution with respect to its ontological and epistemological status. Then, I discuss the advantages of his thesis, and especially the emphasis on the organism as the subject rather than the object of evolution. I argue in detail that his account could benefit from a more exact conception of autonomy, and I discuss six problems related to the operationalization of his concept as applied to various theoretical issues.
The model of major transitions in evolution (MTE) devised by Maynard Smith and Szathmáry has exerted tremendous influence over evolutionary theorists. Although MTE has been criticized for inconsistently combining different types of event, its ongoing appeal lies in depicting hierarchical increases in complexity by means of evolutionary transitions in individuality (ETIs). In this paper, we consider the implications of major evolutionary events overlooked by MTE and its ETI-oriented successors, specifically the biological oxygenation of Earth, and the acquisitions of mitochondria and plastids. By reflecting on these missed events, we reveal a central philosophical disagreement over the explanatory goals of major transitions theory that has yet to be made explicit in the literature. We go on to argue that this philosophical disagreement is only reinforced by Szathmáry’s recent revisions of MTE in the form of MTE 2.0. This finding motivates us to propose an alternative explanatory strategy: specifically, an interactionist metabolic perspective on major transitions. A metabolic framework not only avoids many of the criticisms that beset classic and revised MTE models, but also accommodates missing events and provides crucial explanatory components for standard major transitions. Although we do not provide a full-blown alternative theory and do not claim to achieve unity, we explain why foregrounding metabolism is crucial for any attempt to capture the major turning points in evolution, and why it does not lead to unmanageable pluralism.
The history of life seems to be characterized by three large-scale trends in complexity: (1) the rise in complexity in the sense of hierarchy, in other words, an increase in the number of levels of organization within organisms; (2) the increase in complexity in the sense of differentiation, that is, a rise in the number of different part types at the level just below the whole; and (3) a downward trend, the loss of differentiation at the lowest levels in organisms, a kind of complexity drain within the parts. Here, I describe the three trends, outlining the evidence for each and arguing that they are connected with each other, that together they constitute an evolutionary syndrome, one that has recurred a number times over the history of life. Finally, in the last section, I offer an argument connecting the third trend to the reduction at lower levels of organization in “autonomy”, or from a different perspective, to an increase in what might be called the “machinification” of the lower levels.
What would a Grand Unified Theory of big-scale evolution look like? Here is one answer. It would unify the various trends that have been documented and suspected, the features of life that have been said to increase over its history—body size, fitness, intelligence, versatility, evolvability, energy intensiveness, energy rate density, and complexity-in-the-sense-of-part-types, and complexity-in-the-sense-of-hierarchy. It would show us how these putative trends are related to each other, how they are all the product of some single simple principle or some small set of principles. It would identify and connect all of the variables that are expected to increase over the long haul in evolution, perhaps in a single equation, or if not yet quantifiable, perhaps in a single breath.The obvious unifying candidate is fitness. Natural selection acts to adapt organisms to local circumstances, of course, but it might also act over the long term to produce adaptation on a bigger scale, to produce or ...
ResearchGate has not been able to resolve any references for this publication.