scholarly journals Macroevolutionary patterns of body plan canalization in euarthropods

Paleobiology ◽  
2020 ◽  
Vol 46 (4) ◽  
pp. 569-593
Author(s):  
Cédric Aria
Keyword(s):  
Regulatory Networks ◽  
Morphological Evolution ◽  
Genetic Regulatory Networks ◽  
Cambrian Explosion ◽  
Adaptive Landscape ◽  
Rates Of Evolution ◽  
History Of ◽  
Optimum Type ◽  
Phylogenetic Framework ◽  
Insight Into

AbstractReconstructing patterns of macroevolution has become a central endeavor in paleobiology, because it offers insight into evolutionary models shaping the history of life. As the most diverse and abundant animals since the Cambrian period, arthropods provide copious data to elucidate the emergence of body plans in metazoan lineages. However, information provided by fossils on the tempo and mode of this phenomenon has lacked a recent synthesis. Here, I investigate macroevolutionary patterns of morphological evolution in Euarthropoda using a combined extinct and extant dataset optimized for multivariate analyses. Overall ordination patterns between the main morphogroups are consistent with another, independently coded, extant-only dataset providing molecular and morphological rates of evolution. Based on a “deep split” phylogenetic framework, total-group Mandibulata and Arachnomorpha emerge as directional morphoanatomical lineages, with basal fossil morphogroups showing heterogeneously spread-out occupations of the morphospace. In addition to a more homogeneous morphological variation, new morphogroups arose by successive reductions of translation distances; this pattern was interrupted only by terrestrialization events and the origin of pancrustaceans. A displaced optimum type of model is proposed to explain the fast assembly of canalized body plans during the Cambrian, with basal fossil morphogroups fitting intermediate fitness peaks in a moving adaptive landscape. Given time constraints imposed by the paleontological evidence, and owing to the interplay between canalization and modularity, as well as a decoupling between molecular and morphological rates, the rise of euarthropods would support the view that the swiftness of the Cambrian explosion was mostly associated with the buildup of genetic regulatory networks.

scholarly journals Understanding the evolution of personality requires the study of mechanisms behind the development and life history of personality traits

2018 ◽  
Vol 14 (2) ◽  
pp. 20170740 ◽  
Author(s):  
Fritz Trillmich ◽  
Thorben Müller ◽  
Caroline Müller
Keyword(s):  
Regulatory Networks ◽  
Personality Development ◽  
Animal Personality ◽  
Individual Variability ◽  
Genetic Regulatory Networks ◽  
Emergent Properties ◽  
Proximate Mechanisms ◽  
History Of ◽  
Behavioural Phenotypes ◽  
Epigenetic Processes

Research on animal personality explains the coexistence of distinct behavioural phenotypes within a species and demonstrates limits to individual plasticity. However, the mechanisms guiding the lifelong development of personality should receive more attention, because many elements of personality are emergent properties of interactions between the environment and an individual's genetic background. In these interactions, mechanisms (e.g. genetic regulatory networks, epigenetic processes and neuroendocrine regulation) influencing personality may be modified. An approach integrating proximate mechanisms with a view of lifelong personality development will crucially improve understanding stability, plasticity and inter-individual variability of personalities and clarify the effects of selection on the phenomenon.

scholarly journals Dynamic evolutionary change in post-Paleozoic echinoids and the importance of scale when interpreting changes in rates of evolution

2015 ◽  
Vol 112 (12) ◽  
pp. 3758-3763 ◽  
Author(s):  
Melanie J. Hopkins ◽  
Andrew B. Smith
Keyword(s):  
Initial Phase ◽  
Evolutionary History ◽  
Morphological Evolution ◽  
Morphological Diversity ◽  
Feeding Strategies ◽  
Geological Time ◽  
Internal Constraints ◽  
Rates Of Evolution ◽  
History Of ◽  
Morphological Innovation

How ecological and morphological diversity accrues over geological time has been much debated by paleobiologists. Evidence from the fossil record suggests that many clades reach maximal diversity early in their evolutionary history, followed by a decline in evolutionary rates as ecological space fills or due to internal constraints. Here, we apply recently developed methods for estimating rates of morphological evolution during the post-Paleozoic history of a major invertebrate clade, the Echinoidea. Contrary to expectation, rates of evolution were lowest during the initial phase of diversification following the Permo-Triassic mass extinction and increased over time. Furthermore, although several subclades show high initial rates and net decreases in rates of evolution, consistent with “early bursts” of morphological diversification, at more inclusive taxonomic levels, these bursts appear as episodic peaks. Peak rates coincided with major shifts in ecological morphology, primarily associated with innovations in feeding strategies. Despite having similar numbers of species in today’s oceans, regular echinoids have accrued far less morphological diversity than irregular echinoids due to lower intrinsic rates of morphological evolution and less morphological innovation, the latter indicative of constrained or bounded evolution. These results indicate that rates of evolution are extremely heterogenous through time and their interpretation depends on the temporal and taxonomic scale of analysis.

scholarly journals From commensalism to parasitism in Carapidae (Ophidiiformes): heterochronic modes of development?

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1786 ◽  
Author(s):  
Eric Parmentier ◽  
Déborah Lanterbecq ◽  
Igor Eeckhaut
Keyword(s):  
Developmental Process ◽  
Morphological Characteristics ◽  
Sister Group ◽  
Adaptive Landscape ◽  
Way Of Life ◽  
Monophyletic Cluster ◽  
History Of ◽  
Phylogenetic Framework ◽  
Head Morphology ◽  
Iterative Evolution

Phenotypic variations allow a lineage to move into new regions of the adaptive landscape. The purpose of this study is to analyse the life history of the pearlfishes (Carapinae) in a phylogenetic framework and particularly to highlight the evolution of parasite and commensal ways of life. Furthermore, we investigate the skull anatomy of parasites and commensals and discuss the developmental process that would explain the passage from one form to the other. The genusCarapusforms a paraphyletic grouping in contrast to the genusEncheliophis, which forms a monophyletic cluster. The combination of phylogenetic, morphologic and ontogenetic data clearly indicates that parasitic species derive from commensal species and do not constitute an iterative evolution from free-living forms. Although the head morphology ofCarapusspecies differs completely fromEncheliophis,C. homeiis the sister group of the parasites. Interestingly, morphological characteristics allowing the establishment of the relation betweenCarapus homeiandEncheliophisspp. concern the sound-producing mechanism, which can explain the diversification of the taxon but not the acquisition of the parasite morphotype.Carapus homeialready has the sound-producing mechanism typically found in the parasite form but still has a commensal way of life and the corresponding head structure. Moreover, comparisons between the larval and adult Carapini highlight that the adult morphotype “Encheliophis” is obtained by going beyond the adult stage reached byCarapus. The entrance into the new adaptive landscape could have been realised by at least two processes: paedomorphosis and allometric repatterning.

The Subaltern Speak- A Study On The Culture Of The Arunachalis With Special Reference To Mamang Dai’s The Legends Of Pensam

2019 ◽  
Vol 5 (4) ◽  
pp. 14-20
Author(s):  
Ms. Cheryl Antonette Dumenil ◽  
Dr. Cheryl Davis
Keyword(s):  
Special Reference ◽  
Small World ◽  
Natural World ◽  
Arunachal Pradesh ◽  
North East India ◽  
North East ◽  
Shared History ◽  
History Of ◽  
And Gender ◽  
Insight Into

North- East India is an under veiled region with an awe-inspiring landscape, different groups of ethnic people, their culture and heritage. Contemporary writers from this region aspire towards a vision outside the tapered ethnic channel, and they represent a shared history. In their writings, the cultural memory is showcased, and the intensity of feeling overflows the labour of technique and craft. Mamang Dai presents a rare glimpse into the ecology, culture, life of the tribal people and history of the land of the dawn-lit mountains, Arunachal Pradesh, through her novel The Legends of Pensam. The word ‘Pensam’ in the title means ‘in-between’,  but it may also be interpreted as ‘the hidden spaces of the heart’. This is a small world where anything can happen. Being adherents of the animistic faith, the tribes here believe in co-existence with the natural world along with the presence of spirits in their forests and rivers. This paper attempts to draw an insight into the culture and gender of the Arunachalis with special reference to The Legends of Pensam by Mamang Dai.

Collected Documents on the History of the Pskov Orthodox Mission: A Recent Publication

2018 ◽  
pp. 306-312
Author(s):  
Veniamin F. Zima ◽  
Keyword(s):  
Personal Data ◽  
Prisoners Of War ◽  
Inner Life ◽  
Great Patriotic War ◽  
Occupied Territories ◽  
History Of ◽  
Underground Resistance ◽  
The Baltic ◽  
The Church ◽  
Insight Into

The reviewed work is devoted to a significant, and yet little-studied in both national and foreign scholarship, issue of the clergy interactions with German occupational authorities on the territory of the USSR in the days of the Great Patriotic War. It introduces into scientific use historically significant complex of documents (1941-1945) from the archive of the Office of the Metropolitan Sergius (Voskresensky) of Vilnius and Lithuania, patriarchal exarch in Latvia and Estonia, and also records from the investigatory records on charges against clergy and employees concerned in the activities of the Pskov Orthodox Mission (1944-1990). Documents included in the publication are stored in the archives of Moscow, St. Petersburg, Estonia, Lithuania, Leningrad, Novgorod, and Pskov regions. They allow some insight into nature, forms, and methods of the Nazi occupational regime policies in the conquered territories (including policies towards the Church). The documents capture religious policies of the Nazis and inner life of the exarchate, describe actual situation of population and clergy, management activities and counterinsurgency on the occupied territories. The documents bring to light connections between the exarchate and German counterintelligence and reveal the nature of political police work with informants. They capture the political mood of population and prisoners of war. There is information on participants of partisan movement and underground resistance, on communication net between the patriarchal exarchate in the Baltic states and the German counterintelligence. Reports and dispatches of the clergy in the pay of the Nazis addressed to the Metropolitan Sergius (Voskresensky) contain detailed activity reports. Investigatory records contain important biographical information and personal data on the collaborators. Most of the documents, being classified, have never been published before.

The History of the Judahite Bench Tomb

2018 ◽  
Author(s):  
Matthew Suriano
Keyword(s):  
Iron Age ◽  
Hebrew Bible ◽  
Cultural Practices ◽  
Seventh Century ◽  
Mortuary Practices ◽  
Iron Age Ii ◽  
Gradual Development ◽  
History Of ◽  
The Dead ◽  
Insight Into

The history of the Judahite bench tomb provides important insight into the meaning of mortuary practices, and by extension, death in the Hebrew Bible. The bench tomb appeared in Judah during Iron Age II. Although it included certain burial features that appear earlier in the Middle and Late Bronze Ages, such as burial benches, and the use of caves for extramural burials, the Judahite bench tomb uniquely incorporated these features into a specific plan that emulated domestic structures and facilitated multigenerational burials. During the seventh century, and continuing into the sixth, the bench tombs become popular in Jerusalem. The history of this type of burial shows a gradual development of cultural practices that were meant to control death and contain the dead. It is possible to observe within these cultural practices the tomb as a means of constructing identity for both the dead and the living.

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