A discussion on the structure and evolution of the Red Sea and the nature of the Red Sea, Gulf of Aden and Ethiopia rift junction - The evolution of the Gulf of Aden

Marine geological and geophysical data from the International Indian Ocean Expedition, especially from cruise 16 of R. R. S. Discovery , have made it possible to prepare new charts of the bathymetry and the magnetic anomaly field which, together with other data, enable the evolutionary history of the Gulf of Aden to be worked out. Over the past 10 Ma the theory of seafloor spreading can account satisfactorily for the features of the Sheba Ridge and provides evidence of spreading rates in the direction of the fracture zones varying from 0.9 cm a -1 per limb in the west to 1.1 cm a -1 per limb in the east. Between the initial creation of the Gulf and 10 Ma ago, the evolution is less certain, although the geophysical evidence indicates that the crustal structure of the Gulf outside the Sheba Ridge is oceanic.

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Weizhao Yang ◽  
Nathalie Feiner ◽  
Catarina Pinho ◽  
Geoffrey M. While ◽  
Antigoni Kaliontzopoulou ◽  
...  

AbstractThe Mediterranean basin is a hotspot of biodiversity, fuelled by climatic oscillation and geological change over the past 20 million years. Wall lizards of the genus Podarcis are among the most abundant, diverse, and conspicuous Mediterranean fauna. Here, we unravel the remarkably entangled evolutionary history of wall lizards by sequencing genomes of 34 major lineages covering 26 species. We demonstrate an early (>11 MYA) separation into two clades centred on the Iberian and Balkan Peninsulas, and two clades of Mediterranean island endemics. Diversification within these clades was pronounced between 6.5–4.0 MYA, a period spanning the Messinian Salinity Crisis, during which the Mediterranean Sea nearly dried up before rapidly refilling. However, genetic exchange between lineages has been a pervasive feature throughout the entire history of wall lizards. This has resulted in a highly reticulated pattern of evolution across the group, characterised by mosaic genomes with major contributions from two or more parental taxa. These hybrid lineages gave rise to several of the extant species that are endemic to Mediterranean islands. The mosaic genomes of island endemics may have promoted their extraordinary adaptability and striking diversity in body size, shape and colouration, which have puzzled biologists for centuries.


1992 ◽  
Vol 2 (1) ◽  
pp. 131-146
Author(s):  
Artemis Leontis

Reflection on the history of the novel usually begins with consideration of the social, political, and economic transformations within society that favored the “rise” of a new type of narrative. This remains true even with the numerous and important studies appearing during the past ten years, which relate the novel to an everbroadening spectrum of ideological issues—gender, class, race, and, most recently, nationalism. Yet a history of the genre might reflect not just on the novel’s national, but also its transnational, trajectory, its spread across the globe, away from its original points of emergence. Such a history would take into account the expansion of western markets—the growing exportation of goods and ideas, as well as of social, political, and cultural forms from the West—that promoted the novel’s importation by nonwestern societies. Furthermore, it could lead one to examine the very interesting inverse relationship between two kinds of migration, both of which are tied to the First World’s uneven “development” of the Third. In a world system that draws out natural resources in exchange for technologically mediated goods, the emigration of laborers and intellectuals from peripheral societies to the centers of power of the West and the immigration of a western literary genre into these same societies must be viewed as related phenomena.


2020 ◽  
Vol 66 (3-4) ◽  
pp. 142-150
Author(s):  
Jessica Worthington Wilmer ◽  
Andrew P. Amey ◽  
Carmel McDougall ◽  
Melanie Venz ◽  
Stephen Peck ◽  
...  

Sclerophyll woodlands and open forests once covered vast areas of eastern Australia, but have been greatly fragmented and reduced in extent since European settlement. The biogeographic and evolutionary history of the biota of eastern Australia’s woodlands also remains poorly known, especially when compared to rainforests to the east, or the arid biome to the west. Here we present an analysis of patterns of mitochondrial genetic diversity in two species of Pygopodid geckos with distributions centred on the Brigalow Belt Bioregion of eastern Queensland. One moderately large and semi-arboreal species, Paradelma orientalis, shows low genetic diversity and no clear geographic structuring across its wide range. In contrast a small and semi-fossorial species, Delma torquata, consists of two moderately divergent clades, one from the ranges and upland of coastal areas of south-east Queensland, and other centred in upland areas further inland. These data point to varying histories of geneflow and refugial persistance in eastern Australia’s vast but now fragmented open woodlands. The Carnarvon Ranges of central Queensland are also highlighted as a zone of persistence for cool and/or wet-adapted taxa, however the evolutionary history and divergence of most outlying populations in these mountains remains unstudied.


1978 ◽  
Vol 13 (2) ◽  
pp. 180-193
Author(s):  
Ruth Lapidoth

The strait of Bab al-Mandeb, “the gate of tears” or “the gate of the wailing yard”, joins the high seas of the Gulf of Aden and the Indian Ocean to those of the Red Sea. The name is primarily used by geographers to designate the narrowest part of the passage, between Ras Bab al-Mandeb on the Asian shore and Ras Siyan in Africa. At this point it is bordered on the east by the Yemen Arab Republic (Northern Yemen) and the People's Democratic Republic of Yemen (Southern Yemen), and in the west by the Republic of Djibouti (formerly the French Territory of the Afars and Issas). About 14 miles farther north, where the Red Sea (or, for that matter, the strait) is nearly 20 miles wide, lies the coast of Ethiopia (the province of Eritrea). All the riparians claim a territorial sea of 12 miles, and the Yemen Arab Republic, as well as the People's Democratic Republic of Yemen, also claim jurisdiction for certain purposes in an additional zone of 6 miles.On the eastern shore of the strait of Bab al-Mandeb lies the peninsula of Ras Bab al-Mandeb, which is about 6–10 km. wide. It consists of rocky, volcanic plains with several hills of 200–300 m. The coast of Ras Bab al-Mandeb is surrounded by coral reefs of a width of up to 1500 m. The border between North Yemen and South Yemen passes down the middle of Ras Bab al-Mandeb.


1893 ◽  
Vol 10 (9) ◽  
pp. 396-401
Author(s):  
Henry Hicks

In a recent article on the Pre-Cambrian Rocks of the British Isles in the Journal of Geology, vol. i., No. 1, Sir Archibald Geikie makes the following statement: “There cannot, I think, be now any doubt that small tracts of gneiss, quite comparable in lithological character to portions of the Lewisian rocks of the North-West of Scotland, rise to the surface in a few places in England and Wales. In the heart of Anglesey, for example, a tract of such rocks presents some striking external or scenic resemblance to the characteristic types of ground where the oldest gneiss forms the surface in Scotland and the West of Ireland.” To those who have followed the controversy which has been going on for nearly thirty years between the chiefs of the British Geological Survey and some geologists who have been working amongst the rocks in Wales, the importance of the above admission will be readily apparent; but as it is possible that some may be unable to realize what such an admission means in showing geological progress in unravelling the history of the older rocks in Wales during the past thirty years, a brief summary of the results obtained may possibly be considered useful.


2009 ◽  
Vol 16 (1-2) ◽  
pp. 105-118 ◽  
Author(s):  
Brantly Womack

AbstractAs many distinguished academics and officials have pointed out, the current rise of China is not a completely new phenomenon, but rather the return of China to a position of regional centrality and world economic share that were considered normal less than two hundred years ago.1 This fact underlines the importance of history in putting the present into perspective, and at the same time, to the extent that all history is history of the present, it requires a reevaluation of the structure of China's traditional relationships. Hitherto, China's place in modern social science has been in an exotic corner, a failed oriental despotism. To be sure, traditional China did collapse, and today's China is a different China rising in a different world. We might assume that China is rising now precisely because of its differences from traditional China, that it is the last step toward the end of history rather than a resonance with the past. However, the convenience of such an assumption makes it suspect. If China is simply the latest avatar of Western modernity, then it requires of the West some readjustment, but not rethinking. However, the only certainty about China's rise is that it is a complex phenomenon, and the convenience of constructions such as China-as-Prussia or China-as-Meiji Japan derives from their preemption of open-ended study rather than from their insight into complexity. To the extent that China is China, both past and present require reconsideration.


2020 ◽  
Vol 6 (7) ◽  
Author(s):  
Nicolas Arning ◽  
Daniel J. Wilson

Groundbreaking studies conducted in the mid-1980s demonstrated the possibility of sequencing ancient DNA (aDNA), which has allowed us to answer fundamental questions about the human past. Microbiologists were thus given a powerful tool to glimpse directly into inscrutable bacterial history, hitherto inaccessible due to a poor fossil record. Initially plagued by concerns regarding contamination, the field has grown alongside technical progress, with the advent of high-throughput sequencing being a breakthrough in sequence output and authentication. Albeit burdened with challenges unique to the analysis of bacteria, a growing number of viable sources for aDNA has opened multiple avenues of microbial research. Ancient pathogens have been extracted from bones, dental pulp, mummies and historical medical specimens and have answered focal historical questions such as identifying the aetiological agent of the black death as Yersinia pestis . Furthermore, ancient human microbiomes from fossilized faeces, mummies and dental plaque have shown shifts in human commensals through the Neolithic demographic transition and industrial revolution, whereas environmental isolates stemming from permafrost samples have revealed signs of ancient antimicrobial resistance. Culminating in an ever-growing repertoire of ancient genomes, the quickly expanding body of bacterial aDNA studies has also enabled comparisons of ancient genomes to their extant counterparts, illuminating the evolutionary history of bacteria. In this review we summarize the present avenues of research and contextualize them in the past of the field whilst also pointing towards questions still to be answered.


1970 ◽  
Vol 19 ◽  
pp. 202-220
Author(s):  
Śliwa Joachim

Nicolas Tourtechot Known as Granger (ca. 1680 - 1737) and The Discovery of Upper Egypt A French doctor, who travelled up of the Nile in the first half of 1731, wrote Relation du voyage fait en Égypte […], published in 1745 (soon his book was published in English and German). Tourtechot, during his transit to the south, noted and described several monuments. He realized that in Luxor and Karnak he was seeing the remains of the ancient Thebes, although he presumably never reached the west bank of the Nile, and the information referring to the Theban necropolis was drawn by him from indirect sources. He intended to go further to the south, but in Edfu local riots made him go back. In his report Tourtechot put Greek inscriptions which he had found in several places (Qus, Esna, Akhmim, Sheikh Abade); in the following years these inscriptions were included in specialist studies. Tourtechot’s information about Coptic monasteries which he had visited during his voyage are also considered important (he managed to visit the monasteries of St. Anthony and St. Paul on the Red Sea, which were difficult to reach). He wrote a great deal about the details of everyday life, nature and customs. Dangerous moments and specific curiosities described by Tourtechot make his simple and unpretentious writing more vivid and appealing for the reader. Tourtechot’s work constitutes an important part in the history of studies on the art and topography of ancient Egypt.


Author(s):  
Robert Conger ◽  
Amanda Blum ◽  
Paul A. Erickson

Over the past decade there has been a distinct trend toward implementing computer technology in education. The advent of affordable, student accessible computing power has allowed engineering curricula to follow the trends of computer technology in the engineering workplace. The developments in hardware and software, combined with the explosive entrance of the Internet, have allowed design projects to evolve into elaborate and imaginative endeavors. The enhanced speed at which projects can now be completed allows students the opportunity to undertake tasks of greater magnitude, while the advanced tools now available permit students to solve more sophisticated and lifelike problems. The examination of a senior-level design course, in which students must design and build a maze-solving robot, serves to highlight the educational benefits that stand to be gained through the judicious application of technology. The evolutionary history of this design course demonstrates the remarkable progress that computer technology has allowed in educational settings.


2002 ◽  
Vol 71 (4) ◽  
pp. 131-139 ◽  
Author(s):  
Daniel F.R. Cleary ◽  
Henri Descimon ◽  
Steph B.J. Menken

Clear habitat separation between the sister species Colias alfacariensis and C. hyale is shown when occurring sympatrically. Colias hyale is found more often in moist cultivated pastures while Colias alfacariensis is more abundant in dry uncultivated habitat. Out of a total of 16 loci, no diagnostic loci were found between C. alfacariensis and C. hyale, and both species shared most major polymorphisms. Exceptions were the marked differences in allele frequencies at the HK locus and only C. hyale, but not C. alfacariensis was further invariable at the GOT2 locus, which is usually highly polymorphic in the Pieridae. Colias hyale has a significantly lower level of heterozygosity than its sister species C. alfacariensis. In Colias alfacariensis heterozygosity is highest in the Alps and lowest in the low-lying region of Northern France, Both species show high levels of gene flow over a large geographic area. Within C. alfacariensis, but not in C. hyale, the FST value of the PGI locus is significantly different from zero effectively separating the species into populations with high levels of the ’ b’ allele to the west and North, and low levels of the allele in the Alps and Italy. This could point to selection within the PGI locus in line with the well established pattern of selection at the PGI locus in other species of Colias. Glaciations have been an important force in shaping the evolutionary history of European biota, leading to extinction, but also allowing new species to evolve into the newly available land as the ice sheets retreated. The genetic and distributional pattern found between both Colias species suggests that habitat shifts and subsequent adaptation during glaciations could have played an important role in their speciation.


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