scholarly journals Revisiting the impacts of non-random extinction on the tree-of-life

2013 ◽  
Vol 9 (4) ◽  
pp. 20130343 ◽  
Author(s):  
T. Jonathan Davies ◽  
Kowiyou Yessoufou

The tree-of-life represents the diversity of living organisms. Species extinction and the concomitant loss of branches from the tree-of-life is therefore a major conservation concern. There is increasing evidence indicating that extinction is phylogenetically non-random, such that if one species is vulnerable to extinction so too are its close relatives. However, the impact of non-random extinctions on the tree-of-life has been a matter of recent debate. Here, we combine simulations with empirical data on extinction risk in mammals. We demonstrate that phylogenetically clustered extinction leads to a disproportionate loss of branches from the tree-of-life, but that the loss of their summed lengths is indistinguishable from random extinction. We argue that under a speciational model of evolution, the number of branches lost might be of equal or greater consequences than the loss of summed branch lengths. We therefore suggest that the impact of non-random extinction on the tree-of-life may have been underestimated.

2017 ◽  
Author(s):  
Sandrine Pavoine ◽  
Michael B. Bonsall ◽  
T. Jonathan Davies ◽  
Shelly Masi

AbstractA sixth great mass extinction is ongoing due to the direct and indirect effects of human pressures. However, not all lineages are impacted equally. As humans, we frequently believe that we hold a unique place on Earth. Here, we show that our current impacts on the natural world risk to heighten that expectation. Evolutionary proximity to Homo sapiens emerges as a powerful predictor of extinction risk among mammals. Our analysis shows that the species most closely related to H. sapiens are exposed to a large variety of threat types and that they may also have greater intrinsic sensitivity to threats. Pruning back the tree of life around us will lead to our species being among those with the fewest close relatives. We will erase our evolutionary history, forcing its uniqueness. If no action is taken, we will lose crucial biodiversity for the preservation of Earth ecosystems, and a key reference to what makes us human.


Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 63
Author(s):  
Mohammed A. Dakhil ◽  
Marwa Waseem A. Halmy ◽  
Walaa A. Hassan ◽  
Ali El-Keblawy ◽  
Kaiwen Pan ◽  
...  

Climate change is an important driver of biodiversity loss and extinction of endemic montane species. In China, three endemic Juniperus spp. (Juniperuspingii var. pingii, J.tibetica, and J.komarovii) are threatened and subjected to the risk of extinction. This study aimed to predict the potential distribution of these three Juniperus species under climate change and dispersal scenarios, to identify critical drivers explaining their potential distributions, to assess the extinction risk by estimating the loss percentage in their area of occupancy (AOO), and to identify priority areas for their conservation in China. We used ensemble modeling to evaluate the impact of climate change and project AOO. Our results revealed that the projected AOOs followed a similar trend in the three Juniperus species, which predicted an entire loss of their suitable habitats under both climate and dispersal scenarios. Temperature annual range and isothermality were the most critical key variables explaining the potential distribution of these three Juniperus species; they contribute by 16–56.1% and 20.4–38.3%, respectively. Accounting for the use of different thresholds provides a balanced approach for species distribution models’ applications in conservation assessment when the goal is to assess potential climatic suitability in new geographical areas. Therefore, south Sichuan and north Yunnan could be considered important priority conservation areas for in situ conservation and search for unknown populations of these three Juniperus species.


Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 780
Author(s):  
Krystyna Makowska ◽  
Slawomir Gonkowski

Bisphenol A (BPA) contained in plastics used in the production of various everyday objects may leach from these items and contaminate food, water and air. As an endocrine disruptor, BPA negatively affects many internal organs and systems. Exposure to BPA also contributes to heart and cardiovascular system dysfunction, but many aspects connected with this activity remain unknown. Therefore, this study aimed to investigate the impact of BPA in a dose of 0.05 mg/kg body weight/day (in many countries such a dose is regarded as a tolerable daily intake–TDI dose of BPA–completely safe for living organisms) on the neurochemical characterization of nerves located in the heart wall using the immunofluorescence technique. The obtained results indicate that BPA (even in such a relatively low dose) increases the number of nerves immunoreactive to neuropeptide Y, substance P and tyrosine hydroxylase (used here as a marker of sympathetic innervation). However, BPA did not change the number of nerves immunoreactive to vesicular acetylcholine transporter (used here as a marker of cholinergic structures). These observations suggest that changes in the heart innervation may be at the root of BPA-induced circulatory disturbances, as well as arrhythmogenic and/or proinflammatory effects of this endocrine disruptor. Moreover, changes in the neurochemical characterization of nerves in the heart wall may be the first sign of exposure to BPA.


2019 ◽  
Vol 1 (1) ◽  
Author(s):  
D C Blackburn ◽  
G Giribet ◽  
D E Soltis ◽  
E L Stanley

Abstract Although our inventory of Earth’s biodiversity remains incomplete, we still require analyses using the Tree of Life to understand evolutionary and ecological patterns. Because incomplete sampling may bias our inferences, we must evaluate how future additions of newly discovered species might impact analyses performed today. We describe an approach that uses taxonomic history and phylogenetic trees to characterize the impact of past species discoveries on phylogenetic knowledge using patterns of branch-length variation, tree shape, and phylogenetic diversity. This provides a framework for assessing the relative completeness of taxonomic knowledge of lineages within a phylogeny. To demonstrate this approach, we use recent large phylogenies for amphibians, reptiles, flowering plants, and invertebrates. Well-known clades exhibit a decline in the mean and range of branch lengths that are added each year as new species are described. With increased taxonomic knowledge over time, deep lineages of well-known clades become known such that most recently described new species are added close to the tips of the tree, reflecting changing tree shape over the course of taxonomic history. The same analyses reveal other clades to be candidates for future discoveries that could dramatically impact our phylogenetic knowledge. Our work reveals that species are often added non-randomly to the phylogeny over multiyear time-scales in a predictable pattern of taxonomic maturation. Our results suggest that we can make informed predictions about how new species will be added across the phylogeny of a given clade, thus providing a framework for accommodating unsampled undescribed species in evolutionary analyses.


2008 ◽  
Vol 2 (1) ◽  
pp. 31-36 ◽  
Author(s):  
Isabel Albuquerque M. de Carvalho ◽  
Valéria Santoro Bahia ◽  
Leticia Lessa Mansur

Abstract Functional communication is crucial for independent and efficient communicative behavior in response to every day activities. In the course of dementia progression, cognitive losses may impair these abilities. For this reason, functional communication assessment should be part of a formal assessment to quantify and qualify the impact of deficiency on patients' lives. Objective: To compare functional communication abilities in fronto-temporal lobar degeneration (FLTD) and Alzheimer's disease (AD). Methods: Six AD patients (mean age: 82.50±2.66 years; mean education: 5.67±3.61 years), and eight FTLD patients (mean age: 57.13±9.63 years; mean education: 10.86±6.91 years) had their close relatives answer the Functional Assessment of Communication Skills for Adults (Asha-facs) . Statistical analyses correlated the performance on each of the Asha-facs domains (social communication, communication of basic needs; reading, writing, number concept and daily planning) between both groups. Results: Analyses showed that functional communication was similar for AD and FTLD patients. Only two items had statistical difference, namely 'Comprehension of inference' (AD 6.7±1.33; FTLD 2.43±2.30, p=0.017) and 'capacity to make basic money transactions' (AD 2.17±2.04; FTLD 4.00±0.90, p=0.044). Comparison among the four domains' mean scores revealed no significant difference. Conclusion: The Asha-facs is a useful instrument to characterize functional communication abilities in both FTLD and AD. Nevertheless, the analysis presented for this sample showed that the Asha-facs could not discriminate which aspects of the FTLD and AD differed.


2009 ◽  
Vol 38 (1) ◽  
pp. 5-25
Author(s):  
Marguerite Van Die

Prompted by recent debate and legislation in Canada about the definition of "marriage," this article explores the impact of socio-economic change and stress upon marriage as an institution among the middle class in Victorian Canada. It does this through the lens of "lived religion" as defined by Robert Orsi and others, taking the form of a case study of a marital scandal involving a respected Presbyterian minister in Brantford, Ontario in 1883. This is placed within the wider context of competing definitions of marriage as found in folk tradition and community networks, in various ecclesiastical marriage liturgies, and in marriage, divorce and property law. In its final section it examines the contradictions, tensions and anxieties that surrounded these definitions in late Victorian Canada as a result of changes in people's experience of space and time. It concludes by briefly drawing attention to the nature of "lived religion" and its implications in redefining marriage within a society that today has become highly urbanized, secular and pluralistic.


Author(s):  
Robert K. Logan

In this presentation we will study propagating organization. We begin by examining the evolution and origin of language by briefly reviewing the impact of the phonetic alphabet (Logan 2004a), the evolution of notated language (Logan 2004b), the origin of language and culture (Logan 2006, 2007), the role of collaboration in knowledge management (Logan and Stokes 2004), the impact of “new media” (Logan in preparation). We will then connect this work to the propagating organization of all living organisms (Kauffman et al. in press) where we will show that information in biotic systems are the constraints that instruct living organisms how to operate. We will demonstrate that instructional or biotic information is quite different than the classical notion of information Shannon developed for addressing engineering problems in telecommunications. We also will show that biosemiosis is in some sense equivalent to propagating organization (Kauffman et al. in press). We then conclude our presentation with the speculation that there exist at least seven levels of biosemiosis.


2020 ◽  
Vol 18 (Suppl.1) ◽  
pp. 607-613
Author(s):  
D. Stoyanova ◽  
D. Stoyancheva

This report aims to analyze the impact of state grants upon the effectiveness efficiency of the enterprises in the Agricultural sector. The presence/absence of the correlation between the “received state grants - financial results from the activity of the agricultural enterprises” was studied. The efficiency of agricultural enterprises is expressed through the indicators of profitability and productivity. The empirical data for a period of 10 years 2008 – 2017 were shown in the study. The main activities of the surveyed enterprises are crop, livestock and combined - crop-livestock. Based on the results obtained, it is expected that the receipt of grants will have a positive influence on the performance of enterprises in the agricultural sector, measured by indicators of effectiveness and productivity. The following research hypotheses have been proved: the positive effect of the grant is more obvious in larger agricultural enterprises, which have higher productivity and profitability compared to small and medium-sized farms; agricultural enterprises which receive grants and are characterized by higher investment activity and are also characterized by higher innovation activity; based on the predominant number of crop enterprises, it is assumed that this type of activity leads to the achievement of higher financial results as a result of the activity of the agricultural enterprises; the age of the enterprises, expressed through the years of their activity, contributes significantly to higher profitability and productivity of the carried out activity.


Nanotechnology is a speedily increasing and innovating range of research, where advanced characteristics of resources manufactures on the nanoscale can be exploited as advantages for people at large through various methods or mechanisms of construction. Being a varied technical and scientific arena that brings and covers numerous application kinds, the contribution of nanotechnological innovations is immense for various sectors of construction industries. It also possesses a large future potential for ecological efficiency, which is dire need of the hour. In construction industry there are many factors involved to achieve the major goal of sustainability like smart design, planning through which energy can be saved, resource usage can be reduced and environmental damage can be avoided. No doubt, the application of nanotechnology materials and its various causes on the atmosphere and living organisms are not clearly defined yet which can become a problem. For instance, leakage of materials into the water resources, and seas, as well, discharge of nanoparticles into the air generating dust and exposure to harmful materials during various construction, maintenance and use etc. Considering tremendous revolution in Nanotechnological field there is an important aspect in relation to the impact of nanoparticles and nanomaterials on human health and environment which should be discussed at length. This paper intends to give a research review of current and near future, safety and eco-efficiency applications of nanotechnology to not only improve and maintain but also deal with certain future challenges and directions related to the sustainable development.


2014 ◽  
Vol 3 (1) ◽  
pp. 57
Author(s):  
Abdelaziz Ghanemi ◽  
Besma Boubertakh

Pollution  represents  a  problem  common  to economy and  public  health. Indeed, the public health, because of the  divers’  type of pollutions, is facing divers challenges for which urgent solutions are required.The biology provides approaches not only to deal with the pollution, but also to  obtain  economic  benefits. Some living  organisms  have  particular metabolisms  that allow  them  to  assimilate  and  metabolite  the polluting agents  and thus reduce the  impact  they have on both environment  and public health.  On  the other  hand,  the  metabolic  properties  of  specific organisms make  the  polluting  elements raw materials to  synthesize  other elements that are benefits  for  economy  and  non-toxic  for  the  ecology and  the  biohealth. Yet, other options such as the regulations and laws are  required  to improve the efficiency of these approaches.


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