Area, Continental Drift and Mammalian Diversity

Paleobiology ◽  
1975 ◽  
Vol 1 (2) ◽  
pp. 189-194 ◽  
Author(s):  
Karl W. Flessa
Keyword(s):  
Plate Tectonics ◽  
Continental Drift ◽  
Quantitative Modeling ◽  
South American ◽  
Land Bridge ◽  
Area Effect ◽  
Mammalian Faunas ◽  
Continental Area ◽  
North And South

Mammalian generic, familial, and ordinal diversities correlate significantly with continental area. The area effect is similar in form to that shown for true islands: S = kAz, where S is the diversity, A is the area, and k and z are fitted constants. For mammalian genera and continental area, z equals 0.33, for families, z equals 0.23, and for orders, z equals 0.13.The area effect permits quantitative modeling of extinction due to biotic competition between previously isolated faunas. The Late Cenozoic extinction of North and South American mammalian faunas following the rise of the Panamanian land bridge is overestimated by seven families. The overestimate may result from assumptions of complete biotic interchange and universal competition. The role of plate tectonics in regulating diversity may be extensively modified by regional environmental conditions.

scholarly journals Photographs of silos

2021 ◽  
Author(s):  
Catalina Mejía Moreno
Keyword(s):  
Le Corbusier ◽  
South American ◽  
Grain Elevators ◽  
Trade And Exchange ◽  
The Moment ◽  
The One ◽  
North And South ◽  
Walter Gropius ◽  
Do So

This article explores the dissemination of the photographs and photo-reproductions of the now-canonical North and South American grain elevators, published and disseminated in the early twentieth century in publications such as the 1913 Werkbund Yearbook where Walter Gropius included them as illustrations to his article, and later by Le Corbusier in Vers une architecture, amongst many others. It emphasises that while within architecture discourse the idea of a canon made up of buildings is widely accepted, this article identifies and stresses the role of ‘photographic canons’ as a means to further challenge these constructions. To do so, the article focuses on the moment where these photo-reproductions were consolidated as canonical and the mechanisms that such a construct implied. It investigates the photo-reproductions’ history as objects of trade and exchange, as well as their mobilisation in relation to photographic media and different dissemination platforms to argue that, on the one hand, that this informed their reading as architectural, and thus singular, objects. And on the other, that the materiality of the photo-reproductions’ different instances testifies to their nature as commodities and objects of trade, and therefore to the consolidation of their canonical status.

scholarly journals FIRST ANNOTATED CHECKLIST OF BIRDS OF JICARÓN AND JICARITA: THE SOUTHERNMOST ISLANDS OF THE REPUBLIC OF PANAMA

Tecnociencia ◽  
2020 ◽  
Vol 22 (2) ◽  
pp. 123-149
Author(s):  
Pedro Luis Castillo-Caballero ◽  
Claudio M. Monteza-Moreno ◽  
Oscar Johnson ◽  
George R. Angehr
Keyword(s):  
Potential Role ◽  
Bird Species ◽  
Migratory Species ◽  
Land Bridge ◽  
Isthmus Of Panama ◽  
The Republic ◽  
Annotated Checklist ◽  
North And South America ◽  
North And South

The Isthmus of Panama, the narrowest land bridge between North and South America, is surrounded by a large number of islands (>1500) relatively close to the mainland. However, despite the potential role Panamanian islands have for the conservation of bird species, most avian surveys are conducted on the mainland. The islands of Jicarón and Jicarita, located in Coiba National Park, are of particular interest because these are the southernmost islands in the Republic of Panama. Additionally, previous avian surveys were restricted to Coiba Island, the largest of the park, leaving the avifauna in the rest of the islands poorly known. Here, we provide the first annotated checklist of birds for the islands of Jicarón and Jicarita, where we documented 115 and 53 species, respectively. Of these 23 species represent new records for the park. Further, we documented 10 endemic subspecies and 29 migratory species, of which 7 are warblers. The most frequently observed species were Brown-backed Dove (Leptotila plumbeiceps battyi), Rufous-tailed Hummingbird (Amazilia tzacatl) and Bananaquit (Coereba flaveola). We highlight some species of interest and discuss the potential role of these islands for conservation.

scholarly journals The Chicanery of the Isthmian Links Model

2011 ◽  
Vol 30 (2) ◽  
pp. 200-215 ◽  
Author(s):  
Allan Krill
Keyword(s):  
North America ◽  
Southern Hemisphere ◽  
Plate Tectonics ◽  
Continental Drift ◽  
Land Bridge ◽  
Tropical Conditions ◽  
Gondwana Land ◽  
Oceanic Rocks

Two papers, ‘Gondwana land bridges’ by Charles Schuchert and ‘Isthmian links’ by Bailey Willis, were published together in 1932. They were apparently motivated by Schuchert's desire to defend his paleogeography of fixed continents against the threat of Alfred Wegener's continental mobilism. Schuchert and Willis both held to land-bridge theory but admitted that they could not accept each other's types of bridges. Schuchert insisted that some bridges had to be wide and of continental material, without explaining why he felt this was so. Willis insisted that wide continental bridges were isostatically and volumetrically impossible; so any ancient bridges that had sunk must have been narrow isthmuses of dense oceanic rocks. They wrote separate papers, but issued together, perhaps to lead readers to the impression that a compromise was possible; but it was not. They avoided alerting readers to fatal flaws in both their models, in part by limiting their discussion to the less familiar southern hemisphere (Gondwana) and never mentioning the continental connection between Europe and North America. Willis went further in his inventions than Schuchert, trying to explain the extremes of Permian climate. Fixed-continent paleogeography required glacial conditions at equatorial latitudes and tropical conditions at arctic latitudes. We now understand that these climate differences can only be explained by ‘continental drift’ (or plate tectonics), but in his valiant effort to support fixism, Willis postulated not only tectonic uplifts of oceanic isthmuses, but also uplifts in continental areas that were known to be stable.

RESOLVING SOURCE-TO-SINK DYNAMICS BY MULTI-PROXY DATA FROM THE NORTH AND SOUTH AMERICAN CONTINENTAL SEDIMENTARY ARCHIVES

2020 ◽  
Author(s):  
Barbara Carrapa ◽  
◽  
Andrea Stevens Goddard ◽  
Scott Meek ◽  
Peter G. DeCelles
Keyword(s):  
South American ◽  
Proxy Data ◽  
The North ◽  
Source To Sink ◽  
North And South

scholarly journals Pleistocene Mammals from Pampean Region (Argentina). Biostratigraphic, Biogeographic, and Environmental Implications

Quaternary ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 15
Author(s):  
José Luis Prado ◽  
María Teresa Alberdi ◽  
Jonathan Bellinzoni
Keyword(s):  
South America ◽  
The State ◽  
Historical Study ◽  
South American ◽  
Environmental Implications ◽  
Sedimentary Sequences ◽  
Pampean Region ◽  
Mammalian Faunas ◽  
Pleistocene Mammals ◽  
Fossil Records

The Pampean Region contains sedimentary sequences with abundant mammal fossil records, which constitute the chronological outline of the Plio–Pleistocene of South America. These classic localities have been used for more than a century to correlate with other South American regions. Throughout this time, a series of misinterpretations have appeared. To understand the stratigraphic significance of these localities and the geochronological situation of each unit referring to the Pleistocene, a critical historical study of the antecedents was carried out, evaluating the state of each unit. The biostratigraphic studies of the Pampean Region’s mammalian faunas improved the understanding of biogeographic changes taking into account the environmental fluctuations of the Pleistocene.

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