scholarly journals Is chiropterophily an evolutionary dead end? A phylogenetic test in the pantropical genus Parkia (Leguminosae, Caesalpinioideae, mimosoid clade)

2021 ◽  
Vol 154 (3) ◽  
pp. 432-446
Author(s):  
Lorena Conceição Oliveira ◽  
Doriane Picanço Rodrigues ◽  
Helen C. Fortune Hopkins ◽  
Guthieri Teixeira Colombo ◽  
Michael John Gilbert Hopkins
Keyword(s):  
Cluster Analysis ◽  
Euclidean Distance ◽  
Ancestral State ◽  
Evolutionary Transitions ◽  
Pollination System ◽  
Bat Pollination ◽  
Dead End ◽  
History Of ◽  
Floral Characters ◽  
Pollination Systems

Background and aims – Pollination systems often reflect adaptations to specific groups of pollinators, and these morphological specialisations have been important in the diversification of the angiosperms. Here, we study the evolution of the capitulum and pollination system in the pantropical genus Parkia, which comprises 35 species of trees distributed largely in the forests of South and Central America, Africa, Madagascar, and the Indo-Pacific. The flowers are grouped into capitula that are composed of one, two, or three distinct morphological types, and are principally pollinated either by insects or by bats. Material and methods – Using BEAST, we estimated the ages of nodes in a phylogeny based on four chloroplast regions (matK, trnL, psbA-trnH, and rps16-trnQ) and the nuclear region ITS/18S/26S. This analysis also enabled us to reconstruct the ancestral state of the capitulum and hence infer the ancestral pollination system. Euclidean distance-based cluster analysis was performed to determine which characters are consistently related to a specific pollination system.Key results – Our results indicate that the ancestral capitulum in the genus had three types of flowers and a morphology associated with bat-pollination in both the Paleotropics and Neotropics. In one derived Neotropical clade, the number of floral types in each capitulum was reduced to two (capitulum also bat-pollinated) or one (insect-pollinated). Thus, entomophily, as seen in some Neotropical species of Parkia, has been derived from a bat-pollinated ancestor. Cluster analysis showed that the floral characters were mostly consistent with pollination systems.Conclusion – Chiropterophily is not an evolutionary dead end in Parkia because during the evolutionary history of the genus there has been at least one transition to entomophily. Parkia provides a unique example of evolutionary transitions from chiropterophily to entomophily in a pantropical genus of trees.

scholarly journals The Annihilation of Space: A Bad (Historical) Concept

2021 ◽  
pp. 1-30
Author(s):  
Alexis D. Litvine
Keyword(s):  
Cultural History ◽  
Intellectual History ◽  
Social History ◽  
Economic Consequences ◽  
Cultural Mediation ◽  
Counter Example ◽  
Dead End ◽  
The Social ◽  
History Of ◽  
Representations Of Space

Abstract This article is a reminder that the concept of ‘annihilation of space’ or ‘spatial compression’, often used as a shorthand for referring to the cultural or economic consequences of industrial mobility, has a long intellectual history. The concept thus comes loaded with a specific outlook on the experience of modernity, which is – I argue – unsuitable for any cultural or social history of space. This article outlines the etymology of the concept and shows: first, that the historical phenomena it pretends to describe are too complex for such a simplistic signpost; and, second, that the term is never a neutral descriptor but always an engagement with a form of historical and cultural mediation on the nature of modernity in relation to space. In both cases this term obfuscates more than it reveals. As a counter-example, I look at the effect of the railways on popular representations of space and conclude that postmodern geography is a relative dead end for historians interested in the social and cultural history of space.

scholarly journals Ancestry and evolution of seasonal migration in the Parulidae

2011 ◽  
Vol 279 (1728) ◽  
pp. 610-618 ◽  
Author(s):  
Benjamin M. Winger ◽  
Irby J. Lovette ◽  
David W. Winkler
Keyword(s):  
Phylogenetic Signal ◽  
Rapid Change ◽  
Large Family ◽  
Seasonal Migration ◽  
Ancestral State ◽  
Migratory Behaviour ◽  
Wood Warbler ◽  
Wood Warblers ◽  
History Of ◽  
The Tropics

Seasonal migration in birds is known to be highly labile and subject to rapid change in response to selection, such that researchers have hypothesized that phylogenetic relationships should neither predict nor constrain the migratory behaviour of a species. Many theories on the evolution of bird migration assume a framework that extant migratory species have evolved repeatedly and relatively recently from sedentary tropical or subtropical ancestors. We performed ancestral state reconstructions of migratory behaviour using a comprehensive, well-supported phylogeny of the Parulidae (the ‘wood-warblers’), a large family of Neotropical and Nearctic migratory and sedentary songbirds, and examined the rates of gain and loss of migration throughout the Parulidae. Counter to traditional hypotheses, our results suggest that the ancestral wood-warbler was migratory and that losses of migration have been at least as prevalent as gains throughout the history of Parulidae. Therefore, extant sedentary tropical radiations in the Parulidae represent losses of latitudinal migration and colonization of the tropics from temperate regions. We also tested for phylogenetic signal in migratory behaviour, and our results indicate that although migratory behaviour is variable within some wood-warbler species and clades, phylogeny significantly predicts the migratory distance of species in the Parulidae.

Contemporaneitatea literaturii – o chestiune de metodă

Transilvania ◽  
2021 ◽  
pp. 90-102 ◽  
Author(s):  
Dan Neuman
Keyword(s):  
National Literature ◽  
Global Literature ◽  
Dead End ◽  
History Of ◽  
Romanian Literature

The following article critically deals with Mihai Iovănel's Istoria literaturii române contemporane. 1990-2020 [The History of Contemporary Romanian Literature. 1990-2020] (Polirom, 2021) from three different, yet intertwined, perspectives, namely 1) the methodological turn, highlighted by an overt post-Marxist attempt at interpreting contemporary Romanian literature, 2) the question of what is - or if there is any - literariness in Istoria literaturii române contemporane. 1990-2020, 3) the issue of transcending normative aesthetics into post-aestheticism as a last resort or perhaps as a new dead-end. Finally, the ideological threshold that divides - or rather emphasis - local national literature as substantially distinct from global literature will be tentatively broached.

scholarly journals Conflict and cooperation in eukaryogenesis: implications for the timing of endosymbiosis and the evolution of sex

2015 ◽  
Author(s):  
Arunas L Radzvilavicius ◽  
Neil W Blackstone
Keyword(s):  
Cell Fusion ◽  
Mitochondrial Gene ◽  
Evolutionary Process ◽  
Eukaryotic Cell ◽  
Evolutionary Transition ◽  
Evolutionary Transitions ◽  
Conflict And Cooperation ◽  
Conflict Mediation ◽  
Considerable Debate ◽  
History Of

The complex eukaryotic cell is a result of an ancient endosymbiosis and one of the major evolutionary transitions. The timing of key eukaryotic innovations relative to the acquisition of mitochondria remains subject to considerable debate, yet the evolutionary process itself might constrain the order of these events. Endosymbiosis entailed levels-of-selection conflicts, and mechanisms of conflict mediation had to evolve for eukaryogenesis to proceed. The initial mechanisms of conflict mediation were based on the pathways inherited from prokaryotic symbionts and led to metabolic homeostasis in the eukaryotic cell, while later mechanisms (e.g., mitochondrial gene transfer) contributed to the expansion of the eukaryotic genome. Perhaps the greatest opportunity for conflict arose with the emergence of sex involving whole-cell fusion. While early evolution of cell fusion may have affected symbiont acquisition, sex together with the competitive symbiont behaviour would have destabilised the emerging higher-level unit. Cytoplasmic mixing, on the other hand, would have been beneficial for selfish endosymbionts, capable of using their own metabolism to manipulate the life history of the host. Given the results of our mathematical modelling, we argue that sex represents a rather late proto- eukaryotic innovation, allowing for the growth of the chimeric nucleus and contributing to the successful completion of the evolutionary transition.

scholarly journals Towards a global perspective for Salvia L: Phylogeny, diversification, and floral evolution

2021 ◽  
Author(s):  
Fatemeh Moein ◽  
Ziba Jamzad ◽  
Mohammadreza Rahiminejad ◽  
Jacob Brian Landis ◽  
Mansour Mirtadzadini ◽  
...  
Keyword(s):  
Divergence Time ◽  
Global Perspective ◽  
Ancestral State ◽  
Pollination System ◽  
Divergence Time Estimates ◽  
Corolla Length ◽  
Asian Species ◽  
Show Evidence ◽  
Phylogenetic Resolution ◽  
Lever Mechanism

Premise of this study: Salvia is the most species-rich genus in Lamiaceae, encompassing approximately 1000 species distributed all over the world. We sought a new evolutionary perspective for Salvia by employing macroevolutionary analyses to address the tempo and mode of diversification. To study the association of floral traits with speciation and extinction, we modeled and explored the evolution of corolla length and the lever-mechanism pollination system across our Salvia phylogeny. Methods: We reconstructed a multigene phylogeny for 366 species of Salvia in the broad sense including all major recognized lineages and numerous species from Iran, a region previously overlooked in studies of the genus. Our phylogenetic data in combination with divergence time estimates were used to examine the evolution of corolla length, woody vs. herbaceous habit, and presence vs. absence of a lever mechanism. We investigated the timing and dependence of Salvia diversification related to corolla length evolution through a disparity test and BAMM analysis. A HiSSE model was used to evaluate the dependency of diversification on the lever-mechanism pollination system in Salvia. Key Results: Based on recent investigations and classifications, Salvia is monophyletic and comprises ~1000 species. Our inclusion, for the first time, of a comprehensive sampling for Iranian species of Salvia provides higher phylogenetic resolution for southwestern Asian species than obtained in previous studies. A medium corolla length (15-18mm) was reconstructed as the ancestral state for Salvia with multiple shifts to shorter and longer corollas. Macroevolutionary model analyses indicate that corolla length disparity is high throughout Salvia evolution, significantly different from expectations under a Brownian motion model during the last 28 million years of evolution. Our analyses show evidence of a higher diversification rate of corolla length for some Andean species of Salvia compared to other members of the genus. Based on our tests of diversification models, we reject the hypothesis of a direct effect of the lever mechanism on Salvia diversification. Conclusions: Using a broader species sampling than previous studies, we obtained a well-resolved phylogeny for southwest Asian species of Salvia. Corolla length is an adaptive trait throughout the Salvia phylogeny with a higher rate of diversification in the South American clade. Our results suggest caution in considering the lever-mechanism pollination system as one of the main drivers of speciation in Salvia.

scholarly journals The order of trait emergence in the evolution of cyanobacterial multicellularity

2019 ◽  
Author(s):  
Katrin Hammerschmidt ◽  
Giddy Landan ◽  
Fernando Domingues Kümmel Tria ◽  
Jaime Alcorta ◽  
Tal Dagan
Keyword(s):  
Division Of Labor ◽  
Phenotypic Trait ◽  
Evolutionary Transition ◽  
Evolutionary Transitions ◽  
Differentiated Cells ◽  
Labor Theory ◽  
Significant Events ◽  
Reproductive Life ◽  
History Of ◽  
Multicellular Organisms

AbstractThe transition from unicellular to multicellular organisms is one of the most significant events in the history of life. Key to this process is the emergence of Darwinian individuality at the higher level: groups must become single entities capable of reproduction for selection to shape their evolution. Evolutionary transitions in individuality are characterized by cooperation between the lower level entities and by division of labor. Theory suggests that division of labor may drive the transition to multicellularity by eliminating the trade-off between two incompatible processes that cannot be performed simultaneously in one cell. Here we examine the evolution of the most ancient multicellular transition known today, that of cyanobacteria, where we reconstruct the sequence of ecological and phenotypic trait evolution. Our results show that the prime driver of multicellularity in cyanobacteria was the expansion in metabolic capacity offered by nitrogen fixation, which was accompanied by the emergence of the filamentous morphology and succeeded by a reproductive life cycle. This was followed by the progression of multicellularity into higher complexity in the form of differentiated cells and patterned multicellularity.Significance StatementThe emergence of multicellularity is a major evolutionary transition. The oldest transition, that of cyanobacteria, happened more than 3 to 3.5 billion years ago. We find N2 fixation to be the prime driver of multicellularity in cyanobacteria. This innovation faced the challenge of incompatible metabolic processes since the N2 fixing enzyme (nitrogenase) is sensitive to oxygen, which is abundantly found in cyanobacteria cells performing photosynthesis. At the same time, N2-fixation conferred an adaptive benefit to the filamentous morphology as cells could divide their labour into performing either N2-fixation or photosynthesis. This was followed by the culmination of complex multicellularity in the form of differentiated cells and patterned multicellularity.

Measuring the Fire of Life: A Brief History of Metabolic Measurement

2018 ◽  
pp. 1-4
Author(s):  
John R. B. Lighton
Keyword(s):  
Quantitative Measurement ◽  
Historical Context ◽  
Dead End ◽  
History Of ◽  
Metabolic Measurement

This chapter describes the evolution of respirometry from Leonardo da Vinci’s musings onwards. The works of Boyle, the brilliant and prophetic Mayow, and the well-intentioned but misguided Priestley are described. The bizarre dead-end theory of phlogiston and its apparent validity to the scientists of the day are explained in historical context. The breakthroughs of Lavoisier and Paulze, who realized the central role of oxygen and pioneered the quantitative measurement of metabolism, end the conventional historical part of the chapter, which concludes with a brief description of the deep history of the molecules most important to respirometry.

Phylogenetics of the mycoheterotrophic genus Thismia (Thismiaceae: Dioscoreales) with a focus on the Old World taxa: delineation of novel natural groups and insights into the evolution of morphological traits

2020 ◽  
Vol 193 (3) ◽  
pp. 287-315 ◽  
Author(s):  
Ekaterina A Shepeleva ◽  
Mikhail I Schelkunov ◽  
Michal Hroneš ◽  
Michal Sochor ◽  
Martin Dančák ◽  
...  
Keyword(s):  
Significant Proportion ◽  
Morphological Diversity ◽  
Taxonomic Revision ◽  
Morphological Characters ◽  
Morphological Description ◽  
Molecular Evidence ◽  
Ancestral State ◽  
Old World ◽  
Molecular Phylogenetic ◽  
Floral Characters

Abstract Thismia is a genus of > 80 mycoheterotrophic species characterized by a peculiar appearance and complex floral morphology. A significant proportion of the species and morphological diversity of Thismia has only been uncovered in the past two decades, and new discoveries continue to be made. Given that many new data have recently become available, and the most comprehensive taxonomic revision of the genus from 1938 addresses less than half of the currently known species, previous hypotheses for species relationships and infrageneric taxonomic classification in Thismia was in need of review. Extensive molecular phylogenetic studies of Thismia at the genus level have never been presented. We investigate the phylogenetic relationships of 41 species (and one variety) of Thismia from the Old World. Our study comprises 68 specimens (for 28 of which the data were newly generated), including outgroup taxa broadly representing Thismiaceae (= Burmanniaceae p.p. sensuAPG IV, 2016), and is based on two nuclear and one mitochondrial marker. We use maximum likelihood and Bayesian inference to infer relationships among the taxa. We also constructed a morphological dataset of 12 mostly floral characters, comparing these characters to hypotheses based on molecular evidence to identify putative synapomorphies for major clades and to discuss hypotheses regarding the evolution of structural traits in the genus. Our analyses indicate that the majority of currently accepted infrageneric taxa of Thismia are polyphyletic. We find support for the monophyly of the Old World group, in which we recognize five well-supported lineages (clades); the only New World species studied appears to be related to the Neotropical genus Tiputinia. Ancestral state reconstructions demonstrate that the evolution of most morphological characters was homoplastic, but we identify characters that provide each of the five clades of Old World Thismia with a unique morphological description. The geographical distribution of the species under study is also shown to be consistent with the major clades. Our investigation provides a phylogenetic basis for the development of a novel sectional classification of Thismia reflecting morphological and geographical traits.

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