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Heterochronic shifts are regarded one of the major evolutionary changes acting on developmental modules and underlying the origin of morphological disparity. Conserved characters, rarely subject to heterochronic shifts during the curse of evolution, in contrast could indicate underlying developmental or functional constraints. Here we use the development of the cranial musculature Siberian sturgeon (Acipenser baerii) as a model to investigate the role of heterochrony during the evolution of the craniofacial system of Actinopterygii. Using histology, fluorescent antibody staining and fast propagation-based phase contrast imaging in combination with 3D-reconstruction we describe the development of the branchial and hypobranchial musculature. We show that the development of the first branchial arch is accelerated compared to other basal-branching actinopterygians leading to a more synchronous development with the hyoid arch. A pattern that could relate to the derived migratory behaviour of the neural crest cells in sturgeons. In contrast, the developmental timing of the more posterior branchial musculature, including thecucullarismuscle in the Siberian sturgeon, appears to be highly conserved compared to other Actinopterygii and even Osteognathostomata. This could indicate the presence of functional or developmental constraints underlying the evolution of the muscles at the head/trunk interface.

Climate change affects the functioning of all of the components of food systems, often in ways that exacerbate existing predicaments and inequalities among regions of the world and groups in society. At the same time, food systems are a major cause of climate change, accounting for a third of all greenhouse gas (GHG) emissions. Therefore, food systems can and should play a much bigger role in climate policies. This chapter highlights nine action points for climate change adaptation and mitigation in food systems. The chapter shows that numerous practices, technologies, knowledge and social capital already exist for climate action in food systems, with multiple synergies with other important goals, such as the conservation of biodiversity, the safeguarding of ecosystem services, sustainable land management and reducing social and gender inequalities. Many of these solutions are presently being applied at local scales around the world, even if not at sufficient levels. Hence, the major effort to unleash their potential would involve overcoming various technical, political-economic and structural barriers for their much wider application. Some other solutions require research and development investments now, but will focus on helping us meet the longer-term challenges of climate change in regard to food systems in the second half of this century, when most existing food production practices will face unprecedented challenges. In the short term, these pro-poor policy changes and support systems can have a range of positive effects well beyond food systems without delay. In the long term, investments in research will help ensure food security and ecosystem integrity for coming generations.

Land degradation continues to be an enormous challenge to human societies, reducing food security, emitting greenhouse gases and aerosols, driving the loss of biodiversity, polluting water, and undermining a wide range of ecosystem services beyond food supply and water and climate regulation. Climate change will exacerbate several degradation processes. Investment in diverse restoration efforts, including sustainable agricultural and forest land management, as well as land set aside for conservation wherever possible, will generate co-benefits for climate change mitigation and adaptation and morebroadly for human and societal well-being and the economy. This review highlights the magnitude of the degradation problem and some of the key challenges for ecological restoration. There are biophysical as well as societal limits to restoration. Better integrating policies to jointly address poverty, land degradation, and greenhouse gas emissions and removals is fundamental to reducing many existing barriers and contributing to climate-resilient sustainable development.

Sociological insights are often underutilized in sustainability science. To further strengthen its commitment to interdisciplinary problem-driven, solutions-oriented research, sustainability science can better incorporate fundamental sociological conceptions into its core. We highlight four aspects of sociological thought that we consider crucial for advancing sustainability science research: (1) social construction and critical realism, (2) structure and agency, (3) historical specificity, and (4) collective action. We draw on examples from sociology to support a dynamic understanding of how social relations interact with the bio-geo-physical world. This necessary integration of sociological insights, we argue, is critical to generate comprehensive assessments of the causes and consequences of human-induced environmental change, and tend to be overlooked or oversimplified within the field of sustainability science. Beyond that, it can stimulate the development and implementation of viable solutions to sustainability challenges.

More than 150 years ago, in 1866, Ernst Haeckel published a book in two volumes called Generelle Morphologie der Organismen (General Morphology of Organisms) in the first volume of which he formulated his biogenetic law, famously stating that ontogeny recapitulates phylogeny. Here, we describe Haeckel's original idea as first formulated in the Generelle Morphologie der Organismen and later further developed in other publications until the present situation in which molecular data are used to test the "hourglass model," which can be seen as a modern version of the biogenetic law. We also tell the story about his discovery, while traveling in Norway, of an unknown organism, Magosphaera planula, that was important in that it helped to precipitate his ideas into what was to become the Gastraea theory. We also follow further development and reformulations of the Gastraea theory by other scientists, notably the Russian school. Elias Metchnikoff developed the Phagocytella hypothesis for the origin of metazoans based on studies of a colonial flagellate. Alexey Zakhvatin focused on deducing the ancestral life cycle and the cell types of the last common ancestor of all metazoans, and Kirill V. Mikhailov recently pursued this line of research further.

The vertebrate head as a major novelty is directly linked to the evolutionary success of the vertebrates. Sequential information on the embryonic pattern of cartilaginous head development are scarce, but important for the understanding of its evolution. In this study, we use the oriental fire bellied toad, Bombina orientalis, a basal anuran to investigate the sequence and timing of larval cartilaginous development of the head skeleton from the appearance of mesenchymal Anlagen in post-neurulation stages until the premetamorphic larvae. We use different methodological approaches like classic histology, clearing and staining, and antibody staining to examine the larval skeletal morphology. Our results show that in contrast to other vertebrates, the ceratohyals are the first centers of chondrification. They are followed by the palatoquadrate and the basihyal. The latter later fuses to the ceratohyal and the branchial basket. Anterior elements like Meckel's cartilage and the rostralia are delayed in development and alter the ancestral anterior posterior pattern observed in other vertebrates. The ceratobranchials I-IV, components of the branchial basket, follow this strict anterior-posterior pattern of chondrification as reported in other amphibians. Chondrification of different skeletal elements follows a distinct pattern and the larval skeleton is nearly fully developed at Gosner Stage 28. We provide baseline data on the pattern and timing of early cartilage development in a basal anuran species, which may serve as guidance for further experimental studies in this species as well as an important basis for the understanding of the evolutionary changes in head development among amphibians and vertebrates.

In recent years, a dispute has arisen within detection and attribution science concerning the appropriate methodology for associating individual weather events with anthropogenic climate change. In recent contributions, it has been highlighted that this conflict is seemingly misconstrued even by those participating in it and actually concerns a mixture of first and second order so-called inductive risk considerations—in short, it is about values and the role values should have in science. In this paper, we analyze this methodological conflict and examine the inductive risk considerations and argue that there is also another dimension to consider with respect to values that have to do with what detection and attribution science is for. We suggest a framework for understanding this as a kind of problem-feeding situation and thus an issue of problem–solution coordination between different contexts, where the problem is solved versus where the solution is put to use. This has important implications, not least for whether we should understand this conflict as a genuine methodological one or not.

Soils are essential for life and civilization. They have a long history of political attention, documented at least since Ancient Greece and the Roman Empire. Soil played a key political role in the founding of the USA but gradually lost its clout in the last hundred years. The recent IPCC Special Report on Climate Change and Land may symbolize a return of soils to the political arena. The renewed political interest should be harnessed to leverage sustainable land management, which can create synergies between climate-change mitigation and adaptation while attending to a nexus of additional environmental and socio-economic predicaments. This chapter provides a brief history of the political importance of soils, its links to climate change, and how vested economic and political interests perpetuate unsustainable agricultural practices. It ends on a positive note by outlining a pathway towards a sustainable agricultural future.

More than 150 years ago, in 1866, Ernst Haeckel published a book in two volumes called "Generelle Morphologie der Organismen" (General Morphology of Organisms) in the first volume of which he formulated his Biogenetic law, famously stating that ontogeny recapitulates phylogeny (Rieppel 2019). Here we describe Haeckel´s original idea as first formulated in the “Generelle Morphologie der Organismen” and later further developed in other publications until the present situation in which molecular data are used to test the "hour-glass model", which can be seen as a modern version of the biogenetic law. We also tell the story about his discovery, while travelling in Norway, of an unknown organism, Magosphaera planula, that was important in that it helped to precipitate his ideas into what was to become the Gastraea theory. We also follow the further development and reformulations of the Gastraea theory by other scientists, notably the Russian school (Levit, 2007). Ilya Metchnikov developed the Phagocytella hypothesis for the origin of metazoans based on studies of a colonial flagellate. Alexey Zakhvatin focused on deducing the ancestral life cycle and the cell types of the last common ancestor of all metazoans, and Mikhailov recently pursued this line of research further.

The acquisition of a movable jaw and a jaw joint are key events in gnathostome evolution. Jaws are derived from the neural crest derived pharyngeal skeleton and the transition from jawless to jawed vertebrates consists of major morphological changes, which must have a genetic foundation. Recent studies on the effects of bapx1 knockdown in fish and chicken indicate that bapx1 has acquired such a role in primary jaw joint development during vertebrate evolution, but evidence from amphibians is missing so far. In the present study, we use Ambystoma mexicanum, Bombina orientalis, and Xenopus laevis to investigate the effects of bapx1 knockdown on the development of these three different amphibians. Using morpholinos we downregulated the expression of bapx1 and obtain morphants with altered mandibular arch morphology. In the absence of bapx1 Meckeĺs cartilage and the palatoquadrate jaw joint initially develop separately but during further development the joint cavity between both fills with chondrocytes. This results in the fusion of both cartilages and the loss of the jaw joint. Despite this the jaw itself remains usable for feeding and breathing. We show that bapx1 plays a role in jaw joint maintenance during development and that the morphants morphology possibly mirrors the morphology of the jawless ancestors of the gnathostomes.

This article addresses a central debate in combatting climate change: whether we should focus on reducing CO2 emissions or on removing the emitted CO2 from the atmosphere. We favor the former by arguing against the economic viability of the carbon dioxide removal (CDR) branch of geoengineering. This is of course not a question of either or, but we argue that the perception of CDR as a viable option reduces the willingness to reduce CO2 emissions. Using the recently developed approach of risk–reward nexus (RRN) in the economics of innovation, we question the economic viability of CDR. The main argument is simple: if one uses the new framework of RRN in evaluating the innovations involved in the CDR branch of geoengineering, not only does one include more areas of risk but also one has to consider a broader base for distributing the rewards. Consequently, from RRN’s point of view, it would be less likely to find investing in CDR economically viable for the investor firms. Although the core argument of the paper concerns the economics of CDR, in a final section the paper tries to show that the economic argument has also ethical implications against relying on CDR.

In this paper, we engage with the question of the normative content of the resilience concept. The issues are approached in two consecutive steps. First, we proceed from a narrow construal of the resilience concept – as the ability of a system to absorb a disturbance – and show that under an analysis of normative concepts as evaluative concepts resilience comes out as descriptive. In the second part of the paper, we argue that (1) for systems of interest (primarily social systems or system with a social component) we seem to have options with respect to how they are described and (2) that this matters for what is to be taken as a sign of resilience as opposed to a sign of the lack of resilience for such systems. We discuss the implications of this for how the concept should be applied in practice and suggest that users of the resilience concept face a choice between versions of the concept that are either ontologically or normatively charged.

The vertebrate head/trunk interface is the region of the body where the different developmental programs of the head and trunk come in contact. Many anatomical structures that develop in this transition zone differ from similar structures in the head or the trunk. This is best exemplified by the cucullaris/trapezius muscle, spanning the head/trunk interface by connecting the head to the pectoral girdle. The source of this muscle has been claimed to be either the unsegmented head mesoderm or the somites of the trunk. However most recent data on the development of the cucullaris muscle are derived from tetrapods and information from actinopterygian taxa is scarce. We used classical histology in combination with fluorescent whole-mount antibody staining and micro-computed tomography to investigate the developmental pattern of the cucullaris and the branchial muscles in a basal actinopterygian, the Longnose gar (Lepisosteus osseus). Our results show (1) that the cucullaris has been misidentified in earlier studies on its development in Lepisosteus. (2) Cucullaris development is delayed compared to other head and trunk muscles. (3) This developmental pattern of the cucullaris is similar to that reported from some tetrapod taxa. (4) That the retractor dorsalis muscle of L. osseus shows a delayed developmental pattern similar to the cucullaris. Our data are in agreement with an explanatory scenario for the cucullaris development in tetrapods, suggesting that these mechanisms are conserved throughout the Osteichthyes. Furthermore the developmental pattern of the retractor dorsalis, also spanning the head/trunk interface, seems to be controlled by similar mechanisms.

Xenopus laevis is widely used as a model organism in biological research. Morphological descriptions of the larval cartilaginous skeleton are more than half a century old and comprehensive studies of early cartilage differentiation and development are missing. A proper understanding of early cranial skeletal development in X. laevis requires a detailed description that can function as a baseline for experimental studies. This basis makes it possible to evaluate skeletal defects produced by experiments on gene interactions, such as gain- or loss-of function experiments. In this study, we provide a detailed description of the pattern and timing of early cartilage differentiation and development in the larval head of X. laevis. Methods used include antibody staining, confocal laser scanning microscopy and 3D-reconstruction. Results were than compared to earlier studies based on classical histological approaches and clearing-and-staining. The first cartilage to chondrify is, in contrast to other vertebrates investigated so far, the ceratohyal. The components of the branchial basket chondrify in anterior-to-posterior direction as reported for other amphibians. Chondrification of different cartilages begins at different stages and the majority of cartilages are fully developed at Ziermann and Olsson stage 17. Our baseline data on the pattern and timing of early cartilaginous development in X. laevis is useful for evaluation of experiments which alter head skeletal development as well as for identifying heterochronic shifts in head development in other amphibians.

150 years ago, in 1866, Ernst Haeckel published a book in two volumes called "Generelle Morphologie der Organismen" (General Morphology of Organisms) in which he formulated his biogenetic law, famously stating that ontogeny recapitulates phylogeny. Here we describe Haeckel's original idea and follow its development in the thinking of two scientists inspired by Haeckel, Alexei Sewertzoff and Adolf Naef. Sewertzoff and Naef initially approached the problem of reformulating Haeckel's law in similar ways, and formulated comparable hypotheses at a purely descriptive level. But their theoretical viewpoints were crucially different. While Sewertzoff laid the foundations for a Darwinian evolutionary morphology and is regarded as a forerunner of the Modern Synthesis, Naef was one of the most important figures in 'idealistic morphology', usually seen as a type of anti-Darwinism. Both Naef and Sewertzoff aimed to revise Haeckel's biogenetic law and came to comparable conclusions at the empirical level. We end our review with a brief look at the present situation in which molecular data are used to test the "hour-glass model", which can be seen as a modern version of the biogenetic law.

The head is considered the major novelty of the vertebrates and directly linked to their evolutionary success. Its form and development as well as its function, for example in feeding, is of major interest for evolutionary biologists. In this study, we describe the skeletal development of the cranium and pectoral girdle in Siberian (Acipenser baerii) and Russian sturgeon (A. gueldenstaedtii), two species that are commonly farmed in aquaculture and increasingly important in developmental studies. This study comprises the development of the neuro-, viscero- and dermatocranium and the dermal and chondral components of the pectoral girdle, from first condensation of chondrocytes in prehatchlings to the early juvenile stage and reveals a clear pattern in formation. The otic capsules, the parachordal cartilages, and the trabeculae cranii are the first centers of chondrification, at 8.4mm TL. These are followed by the mandibular, then the hyoid, and later the branchial arches. Teeth form early on the dentary, dermopalatine, and palatopterygoid, and then appear later in the buccal cavity as dorsal and ventral toothplates. With ongoing chondrification in the neurocranium a capsule around the brain and a strong rostrum are formed. Dermal ossifications start to form before closure of the dorsal neurocranial fenestrae. Perichondral ossification of cartilage bones occurs much later in ontogeny. Our results contribute data bearing on the homology of elements such as the lateral rostral canal bone that we regard homologous to the antorbital of other actinopterygians based on its sequence of formation, position and form. We further raise doubts on the homology of the posterior ceratobranchial among Actinopteri based on the formation of the hyoid arch elements. We also investigate the basibranchials and the closely associated unidentified gill-arch elements and show that they are not homologous. J. Morphol. 278:418-442, 2017. © 2017 Wiley Periodicals, Inc.

Sustainability science is an integrative scientific field embracing not only complementary but also contradictory approaches and perspectives for dealing with an array of sustainability challenges.

Background Fox genes are a large family of transcription factors that play diverse roles in the immune system, metabolism, cancer, cell cycle, and animal development. It has been shown that FoxN3 is indispensable for normal craniofacial development in the mouse and the African clawed frog, Xenopus laevis. Morpholino-mediated knockdown of FoxN3 in X. laevis delays overall development of early tadpole stages and causes eye defects, the absence of some cranial nerve branches, and malformations of the cranial skeleton and some cranial muscles, while the skeleton, nerves and muscles of the trunk are unaffected. Results We report a delay in heart morphogenesis, the absence of the interatrial septum, and a reduction and compaction of the ventricular trabeculation after knockdown of FoxN3 in X. laevis. Furthermore, we found malformations of the cucullaris and diaphragmatico-branchialis muscles, two head muscles that develop in the head/trunk interface of X. laevis. Conclusions FoxN3 is necessary for the development of the interatrial septum and trabeculae in the frog heart, as well as the cranial muscles developing in the head/trunk interface. This gives the first evidence for a dependence on the head myogenic program of the cucullaris muscle in an anuran species.

A promising approach for addressing sustainabilityproblems is to recognize the unique conditions of aparticular place, such as problem features and solutioncapabilities, and adopt and adapt solutions developed atother places around the world. Therefore, research andteaching in international networks becomes critical, as itallows for accelerating learning by sharing problemunderstandings, successful solutions, and important contextualconsiderations. This article identifies eight distincttypes of research and teaching collaborations in internationalnetworks that can support such accelerated learning.The four research types are, with increasing intensity ofcollaboration: (1) solution adoption; (2) solution consultation;(3) joint research on different problems; and (4) jointresearch on similar problems. The four teaching types are,with increasing intensity of collaboration: (1) adoptedcourse; (2) course with visiting faculty; (3) joint coursewith traveling faculty; and (4) joint course with travelingstudents. The typology is illustrated by extending existingresearch and teaching projects on urban sustainability inthe International Network of Programs in Sustainability,with partner universities from Europe, North America,Asia, and Africa. The article concludes with challenges andstrategies for extending individual projects into collaborationsin international networks.

Der Zoologe Ernst Haeckel zahlt zu den bekanntesten, zugleich aber auch umstrittensten Naturforschern des 19. und beginnenden 20. Jahrhunderts. Als einer der fruhesten Anhanger und streitbarsten Verfechter der Darwinschen Evolutionstheorie – neben “Darwins Bulldogge” Thomas Henry Huxley – stellt er eine Zentralfigur in der Fruhgeschichte des Darwinismus dar. Doch sein Name steht nicht nur als Symbol fur die Auseinandersetzungen um den Entwicklungsgedanken und dessen Popularisierung in dieser Zeit, sondern auch fur ein aktives Eintreten fur den von ihm formulierten und postulierten Monismus. Haeckel zahlt neben Fritz Muller zu den Ersten, die das “Biogenetische Grundgesetz” formulierten. Ebenso gehen noch heute in der biologischen Terminologie verwendete Begriffe wie Ontogenie, Phylogenie, Okologie, Chorologie und Stamm auf ihn und sein Erstlingswerk “Generelle Morphologie der Organismen” (1866) zuruck. 150 years “Biogenetic Law” The zoologist Ernst Haeckel is one of the most well-known, but also one of the most controversial scientists of the late 19th and early 20th centuries. He was one of the earliest Darwinists and a forceful advocate of evolutionary theory. Together with “Darwin's Bulldog” Thomas Henry Huxley, Haeckel was a central figure in the early history and popularization of Darwinism. But his name is not only a symbol for the disputes about the theory of evolution and its popularization, but also for a campaign for monism, a world-view or philosophy created by Haeckel himself. Together with Fritz Muller, Ernst Haeckel was one of the first to formulate a “Biogenetic Law”. He also created several concepts and terms still in use in biology today, such as “ontogeny”, “phylogeny”, “ecology”, “cholorogy” and “phylum” in his first, and maybe most important book “General Morphology of Organism”, which was published in 1866, 150 years ago.

The Haeckel reception in different European countries has received some attention from historians of biology, but the reception in Scandinavia remains relatively unknown. We have found letters to and from Haeckel to Swedish scientists and students in the Ernst Haeckel House in Jena and in the archives of the Royal Swedish Academy of Sciences (RSAS) in Stockholm. Here we present correspondence with Wilhelm Leche, Sven Loven, and M. G. Retzius, all prominent scientists in Stockholm at the time and members of the RSAS. Most letters cover scientific matters such as the biogenetic law, or are concerned with practical matters such as loans of specimens. Sometimes also political issues are mentioned. In addition, we present a letter from Anton Nystrom, the radical physician, in which he tells of his struggles with the church and the conservatives, and a letter from the explorer and geographer Sven Hedin, written in the midst of the First World War. Examples are also given of letters to Haeckel from students that were inspired by his world view as laid out in “Natural History of Creation”. In conclusion, Haeckel’s correspondence with his colleagues in Stockholm gives insights not only into how Haeckel’s ideas were received at the time, but also into the relationships between the Swedish scientists, including their conflicting political views.