A Proposed Terminology of Convergent Evolution

Chapter 18 The book includes 19 selected contributions presented at the 21st Evolutionary Biology Meeting, which took place in Marseille in September 2017. The chapters are grouped into the following five categories: · Genome/Phenotype Evolution · Self/Nonself Evolution · Origin of Biodiversity · Origin of Life · Concepts The annual Evolutionary Biology Meetings in Marseille serve to gather leading evolutionary biologists and other scientists using evolutionary biology concepts, e.g. for medical research. The aim of these meetings is to promote the exchange of ideas to encourage interdisciplinary collaborations. Offering an up-to-date overview of recent findings in the field of evolutionary biology, this book is in invaluable source of information for scientists, teachers and advanced students.International audienceIn this paper, we propose a unified terminology of convergence, in which the phenomenon of convergent evolution is the set, and the types of convergent evolution are subsets of that phenomenon. The set of the convergence phenomenon contains all of the same or very similar traits that have evolved independently in different lineages of organisms. This set contains three subsets that specify the three pathways by which evolution may produce convergence: allo-convergent evolution, iso-convergent evolution, and retro-convergent evolution. Allo-convergent evolution is the independent evolution of the same or very similar new trait from different precursor traits in different lineages, iso-convergent evolution is the independent evolution of the same or very similar new trait from the same precursor trait in different lineages, and retro-convergent evolution is the independent re-evolution of the same or very similar trait to an ancestral trait in different lineages. This unified convergence terminology is proposed to replace the older and confusing terms parallel evolution, reverse evolution, and convergent evolution sensu stricto

Soft-tissue evidence for homeothermy and crypsis in a Jurassic ichthyosaur

Ichthyosaurs are extinct marine reptiles that display a notable external similarity to modern toothed whales. Here we show that this resemblance is more than skin deep. We apply a multidisciplinary experimental approach to characterize the cellular and molecular composition of integumental tissues in an exceptionally preserved specimen of the Early Jurassic ichthyosaur Stenopterygius. Our analyses recovered still-flexible remnants of the original scaleless skin, which comprises morphologically distinct epidermal and dermal layers. These are underlain by insulating blubber that would have augmented streamlining, buoyancy and homeothermy. Additionally, we identify endogenous proteinaceous and lipid constituents, together with keratinocytes and branched melanophores that contain eumelanin pigment. Distributional variation of melanophores across the body suggests countershading, possibly enhanced by physiological adjustments of colour to enable photoprotection, concealment and/or thermoregulation. Convergence of ichthyosaurs with extant marine amniotes thus extends to the ultrastructural and molecular levels, reflecting the omnipresent constraints of their shared adaptation to pelagic life

Dinosaurs, But Not Only: Vertebrate Evolution in the Mesozoic

If we imagine walking through Mesozoic lands, we would be able to observe vertebrates with peculiar combinations of morphological traits, some of which would seem to be intermediary to animals seen today. We would witness a terrestrial vertebrate fauna dominated by dinosaurs of various sizes and diversity, accompanied by many other animal groups that often are overlooked. Current research suggests that many of the main vertebrate clades existing today originated or diversified sometime in the Triassic or Early to Middle Jurassic. Herein, we profile some of the major transformations in both terrestrial and aquatic vertebrate evolution during the Mesozoic. We highlight: the appearance of features that allowed sauropod dinosaurs to become the largest animals to ever walk on Earth’s continents, the appearance of herbivory among the usually carnivorous theropod dinosaurs, and we follow the specific changes that led to the evolution of avian flight. Our Mesozoic tour across the globe will allow us to see how different evolutionary forces led to convergent shifts to quadrupedality in ornithischian dinosaurs and to an aquatic lifestyle in turtles, crocodiles, and plesiosaurs. Last, but not least, we examine changes in the Mesozoic fauna linked to the rise of mammals, and the diversification patterns in several clades of fishes after the End-Permian Mass Extinction

The role of the kidney and the sympathetic nervous system in hypertension.

Nearly one-third of the world's population has hypertension. The human and societal impact of hypertension is enormous. Primary hypertension accounts for 95 % of cases of hypertension in adults. The pathogenesis of primary hypertension is complex. The kidney and the sympathetic nervous system play important roles in the development and maintenance of hypertension. This review discusses their respective roles, the interaction between the two, implications of sympathetic overactivity in kidney disease and therapeutic interventions that have been developed on the basis of this knowledge, especially modulation of the sympathetic nervous system