Biotic invasion, niche stability, and the assembly of regional biotas in deep time: comparison between faunal provinces

Paleobiology ◽  
2016 ◽  
Vol 42 (3) ◽  
pp. 359-379 ◽  
Author(s):  
Mark E. Patzkowsky ◽  
Steven M. Holland

AbstractBiotic invasions in the fossil record provide natural experiments for testing hypotheses of niche stability, speciation, and the assembly and diversity of regional biotas. We compare ecological parameters (preferred environment, occupancy, median abundance, rank abundance) of genera shared between faunal provinces during the Richmondian Invasion in the Late Ordovician on the Laurentian continent. Genera that spread from one faunal province to the other during the invasion (invading shared genera) have high Spearman rank correlations (>0.5) in three of four ecological parameters, suggesting a high level of niche stability among invaders. Genera that existed in both regions prior to and following the invasion (noninvading shared genera) have low correlations (<0.3) and suggest niche shift between lineages that diverged at least 8 Myr earlier. Niche shift did not accumulate gradually over this time interval but appears to have occurred in a pulse associated with the onset of the Taconic orogeny and the switch from warm-water to cool-water carbonates in southern Laurentia.

2017 ◽  
Author(s):  
Hannah L. Kempf ◽  
◽  
Ian O. Castro ◽  
Carrie L. Tyler ◽  
Ashley A. Dineen ◽  
...  

EvoDevo ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alice Laciny

AbstractAs social insects, ants represent extremely interaction-rich biological systems shaped by tightly integrated social structures and constant mutual exchange with a multitude of internal and external environmental factors. Due to this high level of ecological interconnection, ant colonies can harbour a diverse array of parasites and pathogens, many of which are known to interfere with the delicate processes of ontogeny and caste differentiation and induce phenotypic changes in their hosts. Despite their often striking nature, parasite-induced changes to host development and morphology have hitherto been largely overlooked in the context of ecological evolutionary developmental biology (EcoEvoDevo). Parasitogenic morphologies in ants can, however, serve as “natural experiments” that may shed light on mechanisms and pathways relevant to host development, plasticity or robustness under environmental perturbations, colony-level effects and caste evolution. By assessing case studies of parasites causing morphological changes in their ant hosts, from the eighteenth century to current research, this review article presents a first overview of relevant host and parasite taxa. Hypotheses about the underlying developmental and evolutionary mechanisms, and open questions for further research are discussed. This will contribute towards highlighting the importance of parasites of social insects for both biological theory and empirical research and facilitate future interdisciplinary work at the interface of myrmecology, parasitology, and the EcoEvoDevo framework.


1984 ◽  
Vol 62 (8) ◽  
pp. 1548-1555 ◽  
Author(s):  
Pierre Magnan ◽  
Gérard J. FitzGerald

When brook charr, Salvelinus fontinalis Mitchill, are in allopatry in oligotrophic Québec lakes, they feed largely on macrobenthic invertebrates. However, when brook charr cooccur with creek chub, Semotilus atromaculatus Mitchill, they feed largely on zooplankton. In the present study, laboratory experiments showed that creek chub were more effective than brook charr in searching for hidden, patchily distributed prey. The searching efficiency of an individual chub feeding in a group was improved through social facilitation. In contrast, the high level of intraspecific aggression observed in brook charr prevents the formation of such feeding groups. In the laboratory, brook charr were able to displace creek chub from the food source because of interspecific aggression. Data are presented showing that chub are morphologically better adapted than charr to feed on benthos (subterminal orientation of the mouth and protrusible premaxillae), while the charr are better adapted than chub to feed on zooplankton (gill raker structure). Differences in feeding behaviour, morphology, and relative abundance between these species appear to be important in the observed niche shift of brook charr in nature.


2021 ◽  
Vol 16 (1(21)) ◽  
pp. 22-31
Author(s):  
David Bidzinashvili

The new Corona-virus and the contagious disease which it causes, the so called COVID 19, put forward the serious challenges for many countries all over the world and for Georgia among them. Almost the whole world is facing very serious obstacles on the international and national levels. Too many problems emerged in the world countries. To resist against the new disease has become the main priority for each country. The global processes caused by the pandemics have influenced the audit service as well. The uncertainty and unpredictability caused the new risks of deficiencies and activated already existed ones in the new environment. The situation became more complicated due to the fact that it can happen that the auditors do not consider the mentioned risks in the process of planning for audits or the risks may be considered mistakenly. The firms and other economical institutions in which the audit is carried out are obliged to adopt the new rules and changing environments in which their businesses function; they should change the rules of fulfilling the operation, preparing the financial accounts, the processes of their representing the information processes, safety of information shown in the financial accounts, the rules of their preparing; they also evaluate the possibilities of keeping on their activities in the nearest future. The qualified performing of the audit implies the basical elemenst which helps to create such environment where the possibility of the high level audit will be at the maximum. Implementing the quality control implies that such system will include two stages; each of them is directed towards providing the audit processes according the international standards There are several types of the quality improvement system. In all of them the main variable value represents the amount of costs for the proper system. All countries choose the system which provides benefits taking the costs into consideration. There are four main stages in the process of implementation the system which will ensure the high quality audit. Here are four main stages shown in the process of implementation:  The first stage: to carry out diagnostic observation;  The second stage: stating the view;  The third sage: working out the system;  The fourth stage: implementation of the system. The firms and other economical institutions where the audit is carried out are obliged to be reliable with their activities in the changing situation in which their businesses function. The subjects change the rules of carrying out the usual operations, change the open information given in the financial accounts, and estimate the possibilities of maintaining the existing possibilities for the nearest future. It is important to revise some standards out of Audit International Standards and to make them fit for revealing and assessing the risks of essential mistakes and discrepencies. The controlled variation of the standard regulates such issues as the newly corrected risks caused by influences of COVID-19 pandemic on the planned approaches to the audit and also, evaluation of the risks already defined and making changes in them taking into consideration the influence of the errors in the risk evaluations and influence made upon the planned evaluations and audits the changes of which will influence the evaluations of the risks in the inner control of the subject on the previously made imagination of the control environment, in order to define the measures to be taken in order to change the reactions to the mistakes using different measures in order to reach the trustful mechanisms to rely on. International standards of audit– answering to the assessed risks, the checked variation of the standard implies that it maybecome necessary to change the measures of reaction to the changes in the circumstances in order to obtain enough reliable measures and activities to control the situation by means of enough auditory evidences. The auditor has responsibilities to take into consideration that largening the deadlines will cause growth of the period and the risks of the dates of events which will happen in the time interval between accountability date and the date of the conclusion made by audit, the audit is also responsible for any event taking place later in relation to the Covid-19 situation. He is responsible also for evaluation of the fact about financial information. The enterprise functioning within nowadays complex environment taking into consideration the situation of COVID 19, should consider such priority issues as the uncertainty accompanying the Covid situation, related covenants, and others which accompany the pandemic period, among them the region, the financial state of customers and dealers, liquidating and paying capacity. During the process of the risk assessments it should considered that Covid 19 pandemic greatly influenced the global economics and the separate branches such as hotels business, retail sail, tourism and others. As a result of pandemic, it is possible that the number of audit considerations and thee circumstances can modify them which can be conditioned by different circumstances and the audit will state if there are incorrectable improper conditioned due to the circumstances. The audit will make it certain there are unimprovable mistakes which apart and together are essential for the financial accountability and the auditor will conclude that they cannot acquire the proper conditioned which apart or together could be essential financial accounts or the audit will conclude that they are not able to the essential accountability. Important researches were led to assess the appeared situation and it was concluded that the COVID 19 pandemic had influenced the financial situation which showed that the specific actions and procedures became complicated.


Author(s):  
Suzette Worden

The Anthropocene is being suggested as a new geological age replacing the Holocene and is a description of a time interval where significant conditions and processes are profoundly altered by human activity. Artists interested in the earth sciences are using digital media to provide audiences with ways of understanding the issues highlighted in discussions about the Anthropocene. These artists are harnessing data through visualisation and sonification, facilitating audience participation, and are often working in art-science collaborations. These activities demonstrate a transdisciplinary approach that is necessary for confronting the world's most pressing problems, such as climate change. After a discussion of the opportunities provided by visualisation technologies and an overview of the Anthropocene, this chapter explores the following interrelated themes through examples of creative works: (1) nanoscale, (2) geology and deep time, (3) climate, weather, and the atmosphere, (4) extreme places – beyond wilderness, and (5) curatorial practice as environmental care.


Author(s):  
J. Garrecht Metzger ◽  
Jahandar Ramezani ◽  
Samuel A. Bowring ◽  
David A. Fike

Perturbations to the global carbon cycle as recorded in the isotopic compositions of marine deposits have been commonly associated with major shifts in the climate and/or biologic activity, including mass extinctions. The Late Ordovician Guttenberg isotopic carbon excursion (GICE) is a large, globally correlative positive shift (∼3‰) in the carbon isotopic composition of marine carbonates (δ13Ccarb), but its driving mechanism(s) remains ambiguous. This is in large part due to uncertain correlations among Late Ordovician records, as well as complex and poorly constrained temporal relationships of abundant K-bentonite (altered volcanic ash) marker beds deposited in this time interval. Here, we provide new, high-precision U-Pb zircon geochronology by chemical-abrasion−isotope-dilution−thermal ionization mass spectrometry for K-bentonites bounding the GICE in the North American Midcontinent, including robust 206Pb/238U ages (reported with 2σ analytical uncertainty) for two important regional markers: the Deicke (453.35 ± 0.10 Ma) and Millbrig (453.36 ± 0.14 Ma) K-bentonites. The new data from these K-bentonites directly constrain the duration of the GICE to less than 400 k.y. at two well-studied locations in eastern Missouri, United States. The abruptness of the GICE precludes relatively gradual tectonic mechanisms as possible drivers of the excursion and suggests more rapid environmental drivers, such as changes in eustatic sea level associated with pre-Hirnantian glacial activity.


Author(s):  
N. Belala ◽  
D.E. Saїdouni ◽  
R. Boukharrou ◽  
A.C. Chaouche ◽  
A. Seraoui ◽  
...  

The design of real-time systems needs a high-level specification model supporting at the same time timing constraints and actions duration. The authors introduce in this paper an extension of Petri Nets called Time Petri Nets with Action Duration (DTPN) where time is associated with transitions. In DTPN, the firing of transitions is bound to a time interval and transitions represent actions which have explicit durations. The authors give an operational semantics for DTPN in terms of Durational Action Timed Automata (DATA). DTPN considers both timing constraints and durations under a true-concurrency semantics with an aim of better expressing concurrent and parallel behaviours of real-time systems.


2014 ◽  
Vol 27 (2) ◽  
pp. 27-48 ◽  
Author(s):  
Vincent F Ialenti

This paper draws upon perspectives on legal personhood, expert knowledge practices, and social relations influential in STS and anthropology to revisit the legal procedural framing of the United States’ now-defunct high-level nuclear waste repository project at Yucca Mountain. Specifically, it examines how this project reinvented both (a) conventional figures of legal personhood as what is called a ‘reasonably maximally exposed individual’ and (b) legal adjudication’s familiar ‘rule-facts-judge’ template as a frame for establishing the repository licensing regime’s delegation of roles, responsibilities, and duties in response to its unique regulatory horizons that extended millennia into the future. Unpacking the implications of these familiar legal figures being brought to bear on historically unprecedented ‘deep’ timescales, this paper concludes by offering alternative lines of inquiry for interdisciplinary analysis of nuclear energy and its associated waste products.


2021 ◽  
Vol 24 (5) ◽  
pp. 923-943
Author(s):  
Андрей Анатольевич Печников ◽  
Дмитрий Евгеньевич Чебуков

According to the portal Math-Net.Ru a graph of journal citation is constructed. To increase the reliability of the model, the citation time interval was chosen from 2010 to 2021, when the distribution of citation articles stabilized at the level of 3500-4500 citations per year. The structure of link aging is studied and it is shown that their half-life is equal to 8 years. Therefore, the publication date of the cited articles was limited to 2002. For the constructed citation graph, the main properties, such as a small diameter and a high density, are obtained, indicating a high level of scientific communication in the Math-Net.Ru. The absence of the “Matthew effect” as a pronounced advantage in quoting established journals in relation to less well-known ones is shown. Adequacy of the journal citation graph Math-Net.Ru as a model of scientific communication confirmed by comparing the ranking of journals in the citation graph with their SCIENCE INDEX rating in eLIBRARY.RU. A direct moderate relationship between the two rankings is shown. A number of meaningful conclusions are drawn from the analysis of the citation graph.


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