EVOLUTION OF BIRD FLIGHT.   Term Paper ID:15956 Click to get this paper

Essay Subject: Fossil evidence, leg modification into wings, conflicting theories, dynamics of flight, non-flying birds, reasons for flight.... More...

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Paper Abstract: Fossil evidence, leg modification into wings, conflicting theories, dynamics of flight, non-flying birds, reasons for flight. Paper Introduction: The evolution of bird flight is one of the most dramatic events in the evolution of animals since the evolution of land life from aquatic forms. One of the challenges of theorists is to explain how this evolution may have occurred and how flight benefits birds. While advantages to flight can be sought, there is also need to explain why birds such as the emu of Australia, kiwi of New Zealand and African ostrich are flightless. Any attempt to find evolutionary advantage in flight must also take account of these birds that do not fly. The general consensus is that cold-blooded reptiles are the most immediate ancestors of warm-blooded birds. However, the fossil record has not yielded evidence indicating how the front legs of reptiles became transformed into the wing of the bird. Archaeopteryx, the first known fossil bird, had a long bony tail Text of the Paper: The entire text of the paper is shown below. However, the text is somewhat scrambled. We want to give you as much information as we possibly can about our papers and essays, but we cannot give them away for free. In the text below you will find that while disordered, many of the phrases are essentially intact. From this text you will be able to get a solid sense of the writing style, the concepts addressed, and the sources used in the research paper. Over the millenia, natural selection may have favoredanimals whose scales on the rear margins of the front leg became longer andbroadened into feathers. Ornithol. Preliminary Observations on the Paleobiology and Evolution of Teratorns Aves Teratornithidae. Air & Space 1,n.4:4 -51; (Oct.-Nov. Stiles, F. J. Snow and Nelson call loss of flight by a Galapagos Island cormorantand evolution of nocturnal habits by a gull (to avoid frigatebird nestpredation and leptoparasitism) special adaptations related to the isolatedisland habitat (12:137-156). W. Thrust and negative lift are created inflapping by the upstroke (recovery stroke) as air meets the dorsal sides ofthe wings. Domestic chickens have white muscleswith few red fibers (2:57-68). Annee. 21,n.1-2:137-156; 1984.13. The general consensus is that cold-blooded reptiles are the mostimmediate ancestors of warm-blooded birds. B. This situation is one where there is a net vertical lifting forceoperating at right angles to the wing surface. 29,n.6:739-745; 1987.8. 1 ,n.1:117-125; 1983.14. Purification and Primary Structure of Ostrich Pancreatic Polypeptide. The evolution of bird flight is one of the most dramatic events inthe evolution of animals since the evolution of land life from aquaticforms. Downes, W. While advantages toflight can be sought, there is also need to explain why birds such as theemu of Australia, kiwi of New Zealand and African ostrich are flightless.Any attempt to find evolutionary advantage in flight must also take accountof these birds that do not fly. Wolkomir, R. Norberg defends the arboreal theory of flight evolution, saying thatcritics have no evidence to support their contentions that incipientflapping during gliding dramatically reduces animal life span. J. Flight Musculature of Birds Musculus Pectoralis. 15,n.2:1 5-13 ; 1981.2. So,wing atrophy or disappearance when flight is not needed means that thespecies is conserving energy. Egg mass couldreduce flight performance (1:1 5-13 ). J. Flightless survivors either escapedinto the water (e.,g. Niemi, G. Norberg, U. Litthauer, D. Two main theories have been advanced to explain this transition ofreptile leg into bird wing. Pterosaur hindlimbs remainindependent of the wing membrane, as, in other birds (1 :218-239). The wings flap and thrust the bird forward through the air.Wings thrust the air upward and downward to reduce pressure on the wingsurface. Notes on the Behavior of the Costa Rican Sharpbill, Oxyruncus cristatus frater. Biol. Proc. and Tonni, E. Storer, R. 15,n.5:625-628; 1987.4. Flight requires high expenditures of energy. Wash. Schulz, H. Bird pectoralis flight muscles in constant use are 1 -2 times moreefficient than muscles of all other vertebrates, which may be related toevolutionary modifications of basic muscle form for storage, conversion andutilization of energy. New Considerations on the Synthetic Theory of Evolution. The leg to wing modification must also be accompanied by otherweight-reducing modifications to allow flight. the long narrow wings (highaspect ratio) of birds like the European Sand Martin produce lift withlittle drag, and allow rapid flight. Ecol. Devillers notesthat the genome has the potential for dynamic flexibility of expression,with transposable elements, split genes, multigene families andhierarchical organization. A second theory is that bipedal reptiles took to tree climbing andleaping from limb to limb. In this way, the rapid and extensive phenotypicvariations postulated in macroevolution may be created in numerous ways,starting in the egg. Patterns of Morphological Evolution in Bird Genera of New-World and Old-World Peatlands. and Reid, B. It should be noted that flightless birds need not be defenseless.The ostriches, rheas, emus and--cassowaries are all large in size, withgood vision, rapid running abilities and aggressiveness that enablesurvival in the face of moderate predation. Res. Otherearly Pterygota went extinct because they could not fold their wings to fitinto crevices to hide from predators. Five orders of birds and some families of non-passerine birds have agroup of fused thoracic vertebrae called the notarium, with 16 patterns ofvariation in numbers of notarium vertebrae and unfused vertebrae betweenthe notarium and synsacrum. 127,n.2:125-2 4; 1986.12. One of the challenges of theorists is to explain how this evolutionmay have occurred and how flight benefits birds. Most likely Archaeopteryx lacked the breast muscles and keelnecessary for sustaining flight by flapping the wings (15:42 -421). Kinematic reconstruction of pterosaur flightstroke reveals the same downforward component found in birds. C. Entom. Evolution of Vertebrate Flight: An Aerodynamic Model for the Transition from Gliding to Active Flight. The flapping flight of birds is quite complex and not fullyunderstood, though the gliding flight of birds is subject to the same lawsof aerodynamics that govern airplane flight. Themale erects its bright vermilion crest during intense aggressiveinteractions (13:117-125). J. Noamino acid differences were noted (3:628-628). The evolution of flight may be an example of morphologicalconvergence, as it has developed in unrelated animals in variedenvironments. However, the fossil record hasnot yielded evidence indicating how the front legs of reptiles becametransformed into the wing of the bird. The Impact of Vertebrate Predators on Early Arthropod Evolution. New Zealand's flightless wren, Xenicus lyalli is nowextinct. The 36ostrich amino acids are similar in composition to those found in otherbirds, differing from the domestic chicken only by alanine and valineresidues in place of serine and isoleucine at residues three and 18 (7:739-745). Bannasch, R. In conclusion, the scientific community as yet lacks consensusregarding the evolution of bird flight. Schulz notes that the implements of flight, wings and feathers, areintegrated into bird courtship and territoriality via evolution.Compressed neck feathers are part of expression of aggressive excitement inLittle Bustards of both sexes. The flightless dodos and Solitaire, Raphus, became extinct on theMascarene Islands with the introduction of predators by man. 1986).----------------------- 11 Fats, not carbohydrates, are the energy source.Hummingbirds have red muscles with no white fibers. dragonfly nymphs), hid in the leaf litter ordeveloped nocturnal habits, like the cockroach, hiding during the day.Thus, flight is not the only defense available (6:1987). Nat. Pigeons have redmuscle of mixed fiber composition. Am. Int. Similarly, little difference can be found between the amino acids andlipid fatty acids of flightless kiwi birds and domestic hens. 89,n.3:389-4 6; 1987.7. Saunders, 1962.16. With the right flight variables, there is enough nethorizontal thrust over and beyond that needed for balancing body drag.Thus, partially powered flight generates net thrust and may be used to makeshallower flight paths than are found in equilibrium gliding (9:3 3-327). The bird needs thin, hollowbones, lightweight feathers and body parts, extensive bone fusion (e.gpectoral and pelvic girdles, and vertebral column), branching air sacs,oviparous reproduction (rather than viviparous), gonad atrophy betweenbreeding seasons, rapid digestion of concentrated foods, and rapidexcretion of concentrated waste product (15:42 -425). Natural selection may have also favored longeralmost airborne strides. Protein. Themost that can be said is that there is a need for continuing researchbefore a complete and accurate rate of bird flight evolution is attained. New Zealand isan island that had few predators prior to recent predator introductions byman. Milu 5,n.1-2:57-68; 198 .3. Agonistic Behavior, Territorial Behavior and Courtship Display of the Little Bustard, Tetrax tetrax. Cassowaries are so powerfulthat their kick can disembowel or sever the arm of a man (15:439). Suppressed shallow wing beats and advertisement of colorful neckfeathers are part of the territorial display, which may be combined withfoot-stamping, calling and whistling wings on the ground. In searching for the reasons why birds like the ostrich no longerhave flight, examination of the pancreatic polypeptide structure revealslittle differences between the ostrich and other bird species. Basically, gliding produces a continuous vortex sheet that isrolled up into a pair of vortex tubes, while slight flapping producesundulating vortex tubes. Proponents of this theory point tothe wings (front limbs) of Archaeopteryx, which feature a backward-directedfront toe. Despite the difficulty in finding biochemical differences, it may behypothesized that the flightless birds have obtained some type of advantageby not having flight. and Whitney, B. Downes illustrates the importance of flight to avoidance ofpredation, noting that several orders of insects with non-flying stagesliving on the ground became extinct at the end of the Paleozoic because ofincreasing efficient predation by tetrapod hunters with good vision. Flight and the territorial andmating displays related to flight may have a basis at these levels, so theSynthetic Theory of Evolution is worth briefly mentioning. haasti and A. Andersson, M. The situations where bird flight isunnecessary are those of geographic isolation where predators are absent.The flightless Arctic penguins are troubled by few predators. 14,n.1-2:86- 95; 1983.15. P. Padian, K. and Oelofsen, W. This is known as the territorial wingbeatdisplay. Linn. The loss of flight capacity in birds is a case of drasticadapative modification of a macroevolutionary nature occurring (5:153-178). Apteryxaustralis manitelli has 83 percent triglycerols and 8 percentphospholipids, while A. In the course of this gliding from limb tolimb, flapping flight was perfected. The Flight of the Dragonfly. and Norberg, R.A. This aerodynamic model holds regardless of the evolutionarypath of gliding (9:3 3-327). l,n.3-4:265-272; 1981.5. Biol. Auk. Snow, D. W. E. Little Bustard males use the seventh primary feather ofthe wings to make a whistling sound that is an expression of territorialityduring the mating period. Norberg uses these arguments to support the arboreal theory, in whichbirds, bats and pterosaurs had a gliding stage prior to powered flight.Norberg uses the vortex theory to explain the transition from gliding toflapping. Ornithol. Devillers, C. Differences in wing contours make for unequal air pressures, witha partial vacuum on the upper surface and more pressure against the undersurface. J. J. Biol. While theneed to avoid predators is common to most theories, even here there isdebate regarding whether this need interacted with environmental conditionsto produce a rapid transition to flight or a slow, gradual transition. In partially powered flight, the vertical lift forceproduced by one complete wing stroke is sufficient to equal the weight ofthe animal. Fused Thoracic Vertebrae in Birds: Their Occurrence and Possible Significance. Congeneric species of peatland bird in Minnesota and Finlandshow similarities and divergences related to habitat (8:1215-1228).Campbell and Tonni link the evolution of large carnivorous flying birdslike Teratornis merriami during the Tertiary to the development of thesavanna habitat (4:265-272). Thus, aggressive flight may become ritualized over the course ofbird evolution (11:125-2 4). There is noevidence indicating that wing strokes producing vortex rings are a majorproblem in the evolution of wing-powered flight. Evolution of Reversed Sexual Size Dimorphism and Role Partitioning Among Predatory Birds with a Size Scaling of Flight Performance. The reptilian forerunner to the bird may haveran flapping--its front legs in the air, much like a modern day chicken inthe barnyard. Archaeopteryx, the first knownfossil bird, had a long bony tail to balance the front part of its body andwalked on large hind legs--this posture evidently freed the smaller frontlegs from the task of walking, which allowed modification of legs intowings. The model shows that even veryslight wing flapping by a gliding animal is enough to produce flight liftand net thrust. The Lipid Fatty Acid and Amino Acid Composition of Ratite Eggs from Three Different Species of Kiwis. A Functional Analysis of Flying and Walking in Pterosaurs. Soc. New York: W. 24,n.2:153-178; 1985.6. Birds cope with vortexes via a highly developed nervous system whichmanipulates feathers to change--the extension and shape of the wing (16:4 -51). Soc. G. Some authors postulatephysiological improvements attendant to running as the initial catalyst tobird flight evolution. There may even be a common mechanism for micro andmacroevolution, with the main problem being explanation of large rapidtransformations. In that way, aerodynamic dragis minimized. Body, D.R. Hence, anabsence of predators and nocturnal habits to avoid predators are among waysthat flightless birds survive, with flightlessness conserving metabolicenergy. Other authors postulate a shift from ground toarboreal habitat as the pivotal factor in bird flight evolution. Over time, wings which could bear the entireweight of the animal evolved (15:42 -421). Paleobiology 9,n.3:218-239; 198311. Linn. Slow wing beatsand jumping off the ground are part of the male display used to attractfemales. Pept. The flightrecovery stroke is accomplished by functional supracoracoideus reversalaction via enlargement of an acrocoracoid process acting like a pulley.The pterosaur wing membrane system is supported and controlled by stiffenedintercalated fibers oriented as in bird wings. Flight evolution is involved, as selectivefactors accounting for the observed patterns include: 1.) prevention ofbending down of the thoracic ends of the vertebral column during birdflight, 2.) striking prey, and 3.) shock from landing on hard substrates(14:86-95). This backward-directed front toe is evidence that theprehistoric Archaeopteryx was arboreal. Vertebr. oweni have only 65-69 percenttriglycerols along with a higher, 23-24 percent, phospholipid level. M. The Life of Birds. Norberg proposes a modelbased on quasi-stationary aerodynamics. Padian looks at evolution of prehistoric pterosaurs, and concludesthat these animals have all the characteristics of fliers and none of thecharacteristics of gliders. Besides the kiwi, which spends its days in a burrow, New Zealand hasa flightless owl parrot,Strigops habroptilus. Biochem. Welty, J. and Nelson, J. Literature Cited1. On someislands, there are flightless grebes, cormorants and rails. Yamashina Inst. It is likely that Archaeopteryxglided downward from trees in the same fashion as modern day treesquirrels. J. Tail feathers are laterally folded anderected females. Syst. Evolution and Adaptations of Galapagos Sea Birds. In birds like the albatross, theaspect ratio may be 18:1, which produces a lift-to-drag ratio of 4 :1 (4 grams of lift per 1 gram of resistance) (15:422-424). Soc. Campbell, K. Flight displays are also noted in the Costa Rican sharpbill. Devillers attempts to incorporate molecular and developmentalgenetics into discussion of evolution. Paleontol. A blunt rounded front thattapers almost to a point in the rear gives birds a--streamlined tear-dropshape that has less resistance to the air. L. In flapping, the vortex tubes are interrupted androll up into vortex wings. Ecology 66,n.4:1215-1228; 1985.9. 126,n.3:3 3-327; 1985.1 . B. If this paper is not what you are looking for, you can search again: Search for: or Click here to request an essay written just for you.