منابع مشابه
Aridity and hominin environments.
Aridification is often considered a major driver of long-term ecological change and hominin evolution in eastern Africa during the Plio-Pleistocene; however, this hypothesis remains inadequately tested owing to difficulties in reconstructing terrestrial paleoclimate. We present a revised aridity index for quantifying water deficit (WD) in terrestrial environments using tooth enamel δ18O values,...
متن کاملSatellite Based Aridity Mapping
For the instantaneous dryness mapping, the satellite derived aridity index is proposed. The proposed index is derived from the day/night surface temperature and the maximum solar flux, also it is proved that the index corresponds to the thermal admittance from the theoretical analysis of the surface energy balance. From the MODIS LST and reflectance product during 10 years, daily/monthly global...
متن کاملDiversity and niche evolution along aridity gradients in north american lizards (phrynosomatidae).
Deserts occupy approximately 12% of the Earth's land surface, and are thought to have species poor but highly specialized biotas. However, few studies have examined the evolutionary origins of desert biotas and of diversity patterns along aridity gradients. Further, it is unclear if species occurring in more extreme conditions on a given niche axis (i.e., precipitation) are more specialized for...
متن کاملAridity shapes cyanogenesis cline evolution in white clover (Trifolium repens L.).
Adaptive differentiation between populations is often proposed to be the product of multiple interacting selective pressures, although empirical support for this is scarce. In white clover, populations show adaptive differentiation in frequencies of cyanogenesis, the ability to produce hydrogen cyanide after tissue damage. This polymorphism arises through independently segregating polymorphisms...
متن کاملSoils of Namaqualand: Compensations for aridity
The soil mantle in Namaqualand is immature in terms of weathering. Despite or even because of this, the diversity and spatial variability of soil physical and chemical properties is exceptionally high and could be fundamental in governing biodiversity and ecosystem function. In arid landscapes, the way the soil sheds, admits, stores, diverts and transmits water is crucially important. Namaquala...
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ژورنال
عنوان ژورنال: Scientific American
سال: 1909
ISSN: 0036-8733
DOI: 10.1038/scientificamerican09181909-190supp