VI.—Features of Placoderm Diversification and the Evolution of the Arthrodire Feeding Mechanism.

1969 ◽  
Vol 68 (6) ◽  
pp. 123-170 ◽  
Author(s):  
Roger S. Miles
Keyword(s):  
Fossil Record ◽  
Anterior Part ◽  
Parallel Evolution ◽  
Good Evidence ◽  
Point Of View ◽  
Vertical Movements ◽  
Feeding Mechanism ◽  
Jaw Apparatus ◽  
History Of ◽  
Functional Point

SynopsisThe initial adaptive radiation of the Placodermi took place rapidly following the development of the basic placoderm adaptive complex after the ancestral scale covering of the trunk fused into a rigid shield, and not long before the group appears in the fossil record in the Lower Devonian. The radiation was mainly concerned with different ways of living in the benthos of a variety of marine and fresh-water environments; a few nektonic species appear late in the history of the Arthrodira. The fossil record shows the evolution of the orders in their adaptive zones. The zones become increasingly distinct as the orders evolve and become more specific in their adaptations, and the arthrodire, antiarch and rhenanid zones segregate into successively occupied sub-zones. The evolution of the Placodermi has been previously described in terms of improvements in the locomotor mechanism by an analysis of changes in the trunk-armour and pectoral fins. A more detailed description can be given by considering the feeding mechanism as well; this is particularly true of the largest order, the Arthrodira. Study of the feeding mechanism involves the cervical joints as well as the jaws and gnathals. The cervical joints had the same functions in feeding as the anterior part of the vertebral column (“the neck”) in many higher fish. In arthrodires jaw action involved vertical movements of the mandibular lever; the upper jaw apparatus is comparable to the rigid palatoquadrate-maxillary complex of primitive bony fish. The mandible was transformed into a bent lever inBrachyosteusby the development of a small “coronoid” process, but the arthrodire jaw apparatus remained undeveloped in comparison with Actinopterygii and Elasmobranchii. Arthrodire jaw suspension was autostylic. Evidence from the Rhenanida and Ptyctodontida has been interpreted to suggest that this condition was secondary, and that primitive placoderms had an elasmobranch or holocephalan-like palatoquadrate with hyostylic suspension. This view is not entirely supported by the state of the palatoquadrate in primitive arthrodires, but there is no good evidence that placoderms had a complete, open spiracular gill-slit (the aphethoyoid condition). Arthrodire phylogeny cannot yet be described in vertical lines, but four successive levels of organization of increasing efficiency can be recognized; the actinolepid, phlyctaenaspid, coccosteomorph and pachyosteomorph levels. These levels can be defined by simple characters relating to broad adaptations in the locomotor and feeding mechanisms. Evolutionary trends in the Arthrodira include the enlargement of the scapulocoracoid and base of the pectoral fin and the reduction of the spinal plate and flank armour, as the fish gain better control in the water and more myomeres become available for use in swimming; and the enlargement of the nuchal gap and development of the cranio-thoracic joint as powerful muscles are developed to raise the head to give a wide gape, accompanied by the specialization of the gnathals for different modes of feeding. Some of these trends are reversed in compressed, nektonic species. The description of arthrodire phylogeny in terms of changes that can be understood from a functional point of view reveals interesting examples of mosaic and parallel evolution.Parabelosteusn.gen. is erected.

Extinction In The Fossil Record

2003 ◽  
Author(s):  
M. E. J. Newman ◽  
R. G. Palmer
Keyword(s):  
Fossil Record ◽  
Large Scale ◽  
Good Evidence ◽  
Individual Species ◽  
High Turnover ◽  
Mathematical Basis ◽  
History Of ◽  
External Stresses ◽  
Extinction Events

Of the estimated one to four billion species that have existed on the Earth since life first appeared here (Simpson 1952), less than 50 million are still alive today (May 1990). All the others became extinct, typically within about ten million years (My) of their first appearance. It is clearly a question of some interest what the causes are of this high turnover, and much research has been devoted to the topic (see, for example, Raup (1991a) and Glen (1994) and references therein). Most of this work has focussed on the causes of extinction of individual species, or on the causes of identifiable mass extinction events, such as the end-Cretaceous event. However, a recent body of work has examined instead the statistical features of the history of extinction, using mathematical models of extinction processes and comparing their predictions with global properties of the fossil record. In this book we will study these models, describing their mathematical basis, the extinction mechanisms that they incorporate, and their predictions. Before we start looking at the models however, we need to learn something about the trends in fossil and other data which they attempt to model. This is the topic of this introductory chapter. Those well versed in the large-scale patterns seen in the Phanerozoic fossil record may wish to skip or merely browse this chapter, passing on to chapter 2, where the discussion of the models begins. There are two primary colleges of thought about the causes of extinction. The traditional view, still held by most palaeontologists as well as many in other disciplines, is that extinction is the result of external stresses imposed on the ecosystem by the environment (Benton 1991; Hoffmann and Parsons 1991; Parsons 1993). There are indeed excellent arguments in favor of this viewpoint, since we have good evidence for particular exogenous causes for a number of major extinction events in the Earth's history, such as marine regression (sealevel drop) for the late-Permian event (Jablonski 1985; Hallam 1989), and bolide impact for the end-Cretaceous (Alvarez et al. 1980; Alvarez 1983, 1987).

scholarly journals Phylogenetic history of major trilobite clades in relation to paleoenvironment

1992 ◽  
Vol 6 ◽  
pp. 104-104
Author(s):  
Richard A. Fortey ◽  
Robert M. Owen
Keyword(s):  
North Africa ◽  
Deep Water ◽  
Fossil Record ◽  
Lower Cambrian ◽  
Good Evidence ◽  
Major Clade ◽  
Small Shelly Fossils ◽  
Marine Habitats ◽  
History Of

Because trilobites occupied a wide a range of Paleozoic marine habitats they are a good group to examine hypotheses concerning the sites in which new major clades first appear, and their subsequent history of diversification and decline. There are several problems in this endeavour. The first concerns classification. Until a complete phylogenetic classification is available, there is no objective way to assess the equivalence or otherwise of groups which have been claimed as orders. For example, Odontopleurida and Lichida are treated as separate orders in some classifications, but are considered as a single major clade - presumably of ordinal status - in others. Some of the most commonly accepted groups (Olenellida, Ptychopariida) are paraphyletic. The second problem is taphonomic. The first appearance of a major group often coincides with a major extrinsic change, such as a regressive-transgressive couplet. Does the event initiate the novelty, or simply permit it to be preserved? Does such an event “punctuate” the fossil record, such that earlier, ancestral taxa belonging to the same clade go unrecognised?Trilobites are already paleogeographically diversified when they make their first appearance in the Lower Cambrian. Since trilobites constitute a true clade, this implies an earlier phase of vicariance of dispersal which is not recorded in the rocks. In China, Siberia, North America, and North Africa these first occurrences are in rocks of inshore origin: still earlier trilobites may have had thin cuticles which militated against their being preserved in the highest energy environments where “small shelly” fossils occurred. The groups Olenellida, Redlichiida, Corynexochida, Ptychopariina (?Lichida) appear in the early Cambrian. The earliest polymerids with morphology corresponding to deep water, atheloptic, is latest Lower Cambrian (Atops, Australia): there are many such in the mid-Cambrian.Opinions differ on the classification of Agnostida. Our own view relates Agnostina to Eodiscina, and on this view the early representatives of the clade (Lower Cambrian, China) are inshore compared with later agnostid occurrences, which typify outer shelf to slope. Ordovician agnostids are comparatively rare; the youngest agnostids were not confined to deep water sites.There is good evidence of early occurrences of Odontopleurida, Lichida s.s., Illaenina, Proetida and Phacopida in shallow water deposits. Evidence from Asaphida is more equivocal. Colonisation of deeper water habitats from shallow is rapid, although not achieved at the same time in each group. The scenario is of repeated production of deeper water forms from shelf taxa rather than wholesale movement of clades into that environment. After the demise of other groups in the late Devonian, for example, in the youngest Devonian and Carboniferous proetides radiated into deep water habitats. But the last trilobites of all in the Permian were shallow shelf inhabitants.

Perspectives of Reforming the System of Interbudget Relations in Russia (in the Light of the International Experience)

2006 ◽  
pp. 112-127 ◽  
Author(s):  
V. Nazarov
Keyword(s):  
Social Welfare ◽  
Intergovernmental Relations ◽  
International Experience ◽  
Point Of View ◽  
Short History ◽  
History Of

The attempts to reconstruct the instruments of interbudget relations take place in all federations. In Russia such attempts are especially popular due to the short history of intergovernmental relations. Thus the review of the ¬international experience of managing interbudget relations to provide economic and social welfare can be useful for present-day Russia. The author develops models of intergovernmental relations from the point of view of making decisions about budget authorities’ distribution. The models that can be better applied in the Russian case are demonstrated.

Beérkezett könyvek

2008 ◽  
Vol 63 (4) ◽  
pp. 769-770
Author(s):  
Csaba Pléh
Keyword(s):  
New York ◽  
Point Of View ◽  
Cambridge University ◽  
New Science ◽  
Oxford University ◽  
History Of ◽  
The Mind ◽  
Oxford University Press

Danziger, Kurt: Marking the mind. A history of memory . Cambridge University Press, Cambridge, 2008Farkas, Katalin: The subject’s point of view. Oxford University Press, Oxford, 2008MosoninéFriedJudités TolnaiMárton(szerk.): Tudomány és politika. Typotex, Budapest, 2008Iacobini, Marco: Mirroring people. The new science of how we connect with others. Farrar, Straus and Giroux, New York, 2008Changeux, Jean-Pierre. Du vrai, du beau, du bien.Une nouvelle approche neuronale. Odile Jacob, PárizsGazzaniga_n

Thanato-Laboratorien. Theorien von Tod und Sterben und Elias Canettis Buch gegen den Tod

2020 ◽  
Vol 4 (1) ◽  
pp. 67-86
Author(s):  
Elisabeth Heyne
Keyword(s):  
Human Life ◽  
Death And Dying ◽  
Point Of View ◽  
Visual Images ◽  
Elias Canetti ◽  
History Of ◽  
Series Of Experiments ◽  
First Time ◽  
Textual Form ◽  
Or History

AbstractAlthough visual culture of the 21th century increasingly focuses on representation of death and dying, contemporary discourses still lack a language of death adequate to the event shown by pictures and visual images from an outside point of view. Following this observation, this article suggests a re-reading of 20th century author Elias Canetti. His lifelong notes have been edited and published posthumously for the first time in 2014. Thanks to this edition Canetti's short texts and aphorisms can be focused as a textual laboratory in which he tries to model a language of death on experimental practices of natural sciences. The miniature series of experiments address the problem of death, not representable in discourses of cultural studies, system theory or history of knowledge, and in doing so, Canetti creates liminal texts at the margins of western concepts of (human) life, science and established textual form.

History of Tour de France from the Geographical Point of View

2013 ◽  
Vol 22 (3-4) ◽  
pp. 255-277 ◽  
Author(s):  
Vladimír Bačík ◽  
Michal Klobučník
Keyword(s):  
Point Of View ◽  
The Past ◽  
Advanced Technologies ◽  
The World ◽  
Spatial Dimensions ◽  
Tour De France ◽  
Wide Circle ◽  
History Of ◽  
Expert Community ◽  
Geographical Point

Abstract The Tour de France, a three week bicycle race has a unique place in the world of sports. The 100th edition of the event took place in 2013. In the past of 110 years of its history, people noticed unique stories and duels in particular periods, celebrities that became legends that the world of sports will never forget. Also many places where the races unfolded made history in the Tour de France. In this article we tried to point out the spatial context of this event using advanced technologies for distribution of historical facts over the Internet. The Introduction briefly displays the attendance of a particular stage based on a regional point of view. The main topic deals with selected historical aspects of difficult ascents which every year decide the winner of Tour de France, and also attract fans from all over the world. In the final stage of the research, the distribution of results on the website available to a wide circle of fans of this sports event played a very significant part (www.tdfrance.eu). Using advanced methods and procedures we have tried to capture the historical and spatial dimensions of Tour de France in its general form and thus offering a new view of this unique sports event not only to the expert community, but for the general public as well.

The Guatemalan Genocide Through Indigenous Mayan Literature Twenty Years After the Peace Accords: Rigoberta Menchú, Humberto Ak´Abal and Victor Montejo

2017 ◽  
Vol 7 (1) ◽  
pp. 31
Author(s):  
David Caballero Mariscal
Keyword(s):  
Social Exclusion ◽  
Dark Period ◽  
Social Situation ◽  
Point Of View ◽  
Contemporary History ◽  
Rigoberta Menchu ◽  
Testimonial Literature ◽  
History Of ◽  
Peace Accords ◽  
Historical Truth

Guatemala experienced a cruel genocide in the early eighties, in the context of a repressive Conflict. Due to the different governments´ repressive policies, this terrible social situation was little known abroad, and even in the own country. Just after the Peace Accords, several organisms worked to uncover the historical truth. In any case, we cannot forget that testimonial literature is a privileged mean to know this dark period of the contemporary history of Guatemala. This genre is particularly relevant, because the main writers are originally Mayans, and have directly suffered both repression and social exclusion due to ethnic reasons. Rigoberta Menchú, Unmberto Ak´abal and Víctor Montejo represent a new and original point of view in the measure in which they describe feelings and situations from the perspective of those who experience them personally. Testimonial literature or the Testimonio becomes an ethnographic document that allows us to know not just a period but a people who have suffered from repression and exclusion for centuries.

RUSSIAN-BELARUSIAN TUTORIAL "HISTORY OF THE GREAT PATRIOTIC WAR. ESSAYS ON THE SHARED HISTORY"

2020 ◽  
pp. 68-88
Author(s):  
Elena A. Kosovan ◽  
Keyword(s):  
Point Of View ◽  
Joint Work ◽  
Eurasian Economic Union ◽  
Shared History ◽  
Great Patriotic War ◽  
History Of ◽  
Independent States ◽  
The Republic ◽  
Integration Project ◽  
Second World

The paper provides a review on the joint Russian-Belarusian tutorial “History of the Great Patriotic War. Essays on the Shared History” published for the 75th anniversary of the victory in the Great Patriotic War. The tutorial was prepared within the project “Belarus and Russia. Essays on the Shared History”, implemented since 2018 and aimed at publishing a series of tutorials, which authors are major Russian and Belarusian historians, archivists, teachers, and other specialists in human sciences. From the author’s point of view, the joint work of specialists from the Russian Federation and the Republic of Belarus in such a format not only contributes to the deepening of humanitarian integration within the Union state, but also to the formation of a common educational system on the scale of the Commonwealth of Independent States or the Eurasian integration project (Eurasian Economic Union – EEU). The author emphasises the high research and educational significance of the publication reviewed when noting that the teaching of history in general and the history of the Second World War and the Great Patriotic War in particular in post-Soviet schools and institutes of higher education is complicated by many different issues and challenges (including external ones, which can be regarded as information aggression by various extra-regional actors).

The Problem of the Formation of Philosophical Prose in Persian

2019 ◽  
Vol 62 (6) ◽  
pp. 126-137
Author(s):  
Tatyana G. Korneeva
Keyword(s):  
Arabic Language ◽  
Point Of View ◽  
Philosophical Tradition ◽  
Alternative View ◽  
Ibn Sina ◽  
Language Of Science ◽  
Persian Language ◽  
Arab Muslim ◽  
History Of ◽  
Philosophical Texts

The article discusses the problem of the formation of philosophical prose in the Persian language. The first section presents a brief excursion into the history of philosophical prose in Persian and the stages of formation of modern Persian as a language of science and philosophy. In the Arab-Muslim philosophical tradition, representatives of various schools and trends contributed to the development of philosophical terminology in Farsi. The author dwells on the works of such philosophers as Ibn Sīnā, Nāṣir Khusraw, Naṣīr al-Dīn al-Ṭūsī, Aḥmad al-Ghazālī, ʼAbū Ḥāmid al-Ghazālī and gives an overview of their works written in Persian. The second section poses the question whether the Persian language proved able to compete with the Arabic language in the field of science. The author examines the style of philosophical prose in Farsi, considering the causes of creation of Persian-language philosophical texts and defining their target audience. The article presents viewpoints of modern orientalist researchers as well as the views of medieval philosophers who wrote in Persian. We find that most philosophical texts in Persian were written for a public who had little or no knowledge of the Arabic language, yet wanted to get acquainted with current philosophical and religious doctrines, albeit in an abbreviated format. The conclusion summarizes and presents two positions regarding the necessity of writing philosophical prose in Persian. According to one point of view, Persian-language philosophical works helped people who did not speak Arabic to get acquainted with the concepts and views of contemporary philosophy. According to an alternative view, there was no special need to compose philosophical texts in Persian, because the corpus of Arabic philosophical terminology had already been formed, and these Arabic terms were widely and successfully used, while the new Persian philosophical vocabulary was difficult to understand.

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