Detecting footprints with GPR

<p>Recent field research at White Sands National Park, New Mexico, USA, has used ground-penetrating radar to detect the footprints of Pleistocene humans, mammoths, and ground sloths. The technique has been succesful with a range of antenna frequencies and for detecting footprints of many different sizes. Perhaps more importantly, the method has been shown to successfully detect fooprints that are not visible to the human eye, often with sufficent detail to differntiate species. This work raises an obvious question about whether GPR could be used to detect footprints in a range of other contexts, or whether the circumstances seen at White Sands are unique. </p>

Extinction: A Very Short Introduction

Extinction has occurred throughout the history of life, with the result that nearly all the species that have ever existed are now extinct. Extinction: A Very Short Introduction looks at the causes and nature of extinctions, past and present, and the factors that can make a species vulnerable. Summarizing what we know about all of the major and minor extinction events, it examines some of the greatest debates in modern science, such as the relative role of climate and humans in the death of the Pleistocene megafauna, including mammoths and giant ground sloths, and the roles that global warming, ocean acidification, and deforestation are playing in present-day extinctions.

Green Brains & Ground Sloths: A Paleoecology-Based Exercise in Hypothesis Formation

In organismic biology, the formation of ecological and evolutionary hypotheses on the basis of observable morphologies is a central element of research, and by extension of teaching and learning. Often it is necessary to take account of complex combinations of factors, some of which may be far from obvious. In the work described here, hypothesis formation and testing was exercised and studied in a learner-centered and object-based manner using an anachronistic, seemingly “nonsensical” plant, Maclura pomifera (Moraceae), in which the link between structure and function only becomes clear when considering past faunistic environments. The element of the unexpected and the allure of the large animals is thought to add to epistemic curiosity and student motivation to engage in the study of plants.

Antiquarian Dreams: Collections and Competition in the Early Republic

Tales of unusual discoveries made in the limestone caverns of Tennessee and Kentucky began to circulate in the first decade of the nineteenth century. According to Samuel Brown, a doctor based in Lexington, the underground realms presented “scenes so uncommon and so romantic, that the most stupid beholder cannot contemplate them without expressions of the greatest astonishment.” Rather than scholars, however, those delving in the depths were typically miners seeking saltpeter for gunpowder production and other minerals, in the process exposing evidence of earlier visitors to the caves, animal and human. Exploration and exploitation were thus inextricably linked. Brown’s dispatch from the West was accompanied by the bones of fossil mammals and, as if by afterthought, “also an earthen cup, probably Indian, (broken in the carriage).” The significance of fragmentary ground sloths and “the bones of the head of the peccary of South America” found in the caves was debated, but the slight traces of human presence in those subterranean realms also provoked comment. John Clifford, another resident of Lexington, interpreted such ephemeral signs at one location as suggesting that the cave to had . . . been inhabited either by a horde of troglodytes or . . . the scene of some religious mysteries . . . Dead bodies have been found which when first seen were apparently as perfect as at the period when deposited there. . . . “It would be a great desideratum,” he concluded, “to see one of these bodies.” And yet the value to scholarship of the discoveries made in western caves was debatable. The utility of relics as a means to understand the history of the American continent was not universally acknowledged. The scholarly apparatus for pursuing such investigations was meager as well. In particular, the ephemeral character of the community of inquiry interested in the material past—dispersed, divided by class and association, subject to disruption through constant mobility, poor communication, and personal rivalries—had a profound impact on how such relics might be used.