نتایج جستجو برای: decomposing feathers
تعداد نتایج: 9893 فیلتر نتایج به سال:
Here we describe three fossil feathers from the Early Cretaceous Santana Formation of the Araripe Basin, Brazil. Feathers are the most complex multiform vertebrate integuments; they perform different functions, occurring in both avian and non-avian dinosaurs. Despite their rarity, fossil feathers have been found across the world. Most of the Brazilian feather fossil record comes from the Santan...
Effect of Cleaning Regime on Stable-isotope Ratios of Feathers in Japanese Quail (coturnix Japonica)
—Stable-isotope analysis of feathers is an increasingly important source of information on diet and movement of birds. Feathers are typically cleaned with a solvent before analysis, but the effects of this cleaning on the resulting data have not been examined critically. We conducted an experiment to determine whether a cleaning regime affected hydrogen ( D), carbon ( C), and nitrogen ( N) ...
Potential mechanistic mediators of Darwinian fitness, such as stress hormones or sex hormones, have been the focus of many studies. An inverse relationship between fitness and stress or sex hormone concentrations has been widely assumed, although empirical evidence is scarce. Feathers gradually accumulate hormones during their growth and provide a novel way to measure hormone concentrations int...
Ducks have many of the same basic external parts as other fowl, such as chickens. However, some unique characteristics exist in the external anatomies of ducks. For example, a duck's head (shown in Figure 1) differs from a chicken's head in several ways. Ducks have no comb and, other than the crested duck, no head covering other than feathers. The bill of a duck is flatter than the beak of a ch...
A new specimen of the early bird Archaeopteryx shows remarkable plumage preservation, including pennaceous leg feathers. But whether birds went through a four-winged stage, and in what exact functional context feathers evolved remains a matter of debate.
PB cac / accr 31st annual conference, jasper 2005 Abstract Feathers are amongst the most complex epidermal derivatives found in vertebrates. They have complex branched structures, grow from their bases by a unique mechanism, and come in a wide variety of sizes, shapes, structures, and colours. Not only do feathers impart cover, insulation, waterproofing of the body, contribute to flight, tactil...
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