Friday, May 3, 2019

Origin of flight of dinosaurs Research Paper Example | Topics and Well Written Essays - 2000 words

Origin of escape cock of dinosaurs - Research Paper ExampleThese factors will all be discussed with reference to archaeopteryx lithographica, a species generally regarded as creation the common ancestor to modern birds and the chief(a) source of information about the development of flight mechanisms. Archaeopteryx A brief discussion of Archaeopteryx litographica (commonly known as Archaeopteryx) is necessary to understand how instrumental this species is to discovering the mechanisms of flight evolution. Various Archaeopteryx specimens have been implant in the south of Germany, well-preserved due to the qualities of the limestone in which they were found. The Archaeopteryx is commonly described as being the size of a raven and having several features that make it identifiable in the context of modern-day birds flights and a wishbone, for example (Ostrom, 1975). Several of these features suggest that the Archaeopteryx was capable of flight, although, as with many things in evol utionary biology, this is something that freighter never be ascertained. Archaeopteryx also shared several features with dinosaurs, such as having chevrons of increased space in the tail and a specific shape of ankle bone (Ostrom, 1975). This bird-dinosaur morphology is the principle tenableness for thinking that the species is the missing link. The way that Archaeopteryx specimens are conserved in limestone has resulted in the preservation of feather imprints, allowing paleontologists to ascertain that this species may have used feathers in the development of flight mechanisms. This is particularly good demo of some aerial motion because the feathers found show characteristics of flight feathers, meaning that feathers had previously began to evolve for a purpose other than flight (Paul, 2002). Finally, it is important to none that it has not been proven whether Archaeopteryx had the power of upright flight or could simply glide (Padian & Chiappe, 1998). Arboreal Hypothesis Th e arboreal hypothesis (also known as the tree down hypothesis) refers to the idea that dinosaurs first gained flight by jumping from trees and acquiring flight as an evolutionary mechanism to avoid fatal accidents from this method. This hypothesis seems intuitive because flight evolving from an arboreal gliding peg would seem to be relatively easy (Padian & Chiappe, 1998, p15) and because the force of gravity helps rather than hinders (Lewin, 1983, p38). Some studies, such as that of Feduccia (1993) suggest that the shape of the manus (the hand portion of the forelimb) and the pes (the foot portion of the hindlimb) of the Archaeopteryx butt on evidence of perching, tree-dwelling and trunk-climbing due to the curvature of these anatomical elements. However, since this paper was published, another specimen of Archaeopteryx has been discovered (known as the Thermopolis specimen) which has almost complete pes, and thus there is now mounting evidence that the hallux (first digit of the pes) did not display curvature necessary for perching (Mayr et al., 2007). If we consider the Archaeopteryx as arboreal, it is important to understand how and why flight would have developed in this way. The original theory as stated by Othniel C. Marsh in the late 19th century was that Archaeopteryx

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