Wyniki wyszukiwania

1

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

Issledovanie parametrov traektorii poleta pochatkov pri ikh otdelenii na strepernykh plastinakh

100%

Zaviryuha N.

Motrol. Motoryzacja i Energetyka Rolnictwa

|

2013

|

tom 15

|

nr 2

2

Feeding flights of the Black-headed Gull [Larus ridibundus] in the surroundings of Riga

100%

Viksne J., Janaus M.

The Ring

|

1993

|

tom 15

|

nr 1-2

3

On the skimming hypothesis of the origin of insect flight

100%

Rasnitsyn A. P.

Acta Zoologica Cracoviensia

|

2003

|

tom 46

|

nr Suppl.

The skimming hypothesis of the origin of insect flight is considered in several possible scenarios. No scenario is found to be in agreement with available information about the insect fossil record and the environments of early insect evolution.

4

Rudimentary finger claws in a flower-visiting phyllostomid bat

84%

Tschapka M.

Acta Chiropterologica

|

2008

|

tom 10

|

nr 1

5

The extent of the pterosaur flight membrane

84%

Elgin R., Hone D., Frey E.

Acta Palaeontologica Polonica

|

2011

|

tom 56

|

nr 1

The shape and extent of the membranous brachioptagium in pterosaurs remains a controversial topic for those attempting to determine the aerodynamic performance of the first vertebrate fliers. Various arguments in favour of the trailing edge terminating against either the torso or hip, the femur, the ankle, or different locations for various taxa, has resulted in several published reconstructions. Uncertainty over the correct model is detrimental to both aerodynamic and palaeoecological studies that are forced to simultaneously consider multiple and highly variable configurations for individual taxa. A review of relevant pterosaur specimens with preserved soft tissues or impressions of the wing membrane, however, strongly suggests that the trailing edge of the wing extended down to the lower leg or ankle in all specimens where the brachiopatagium is completely preserved. This configuration is seen across a phylogenetically broad range of pterosaurs and is thus likely to have been universally present throughout the Pterosauria. Support for opposing hypotheses where the trailing edge terminates against the body, hip, or knee are based on several specimens where the wing membrane is either incomplete or has undergone post−mortem contraction. An ankle attachment does not rule out a high aspect ratio wing as the curvature of the trailing edge and the ratio of the fore to hind limbs also play a major role in determining the final shape of the membrane.

6

The aerodynamics of big ears in the brown long-eared bat Plecotus auritus

84%

Gardiner J. D., Dimitriadis G., Sellers W. I., Codd J. R.

Acta Chiropterologica

|

2008

|

tom 10

|

nr 2

Wings are the most obvious adaptation bats have for powered flight and differences in wing morphology are known to correlate with flight behaviour. However, the function(s) of ancillary structures such as the ears and tail, which may also play an important role during flight, are less well understood. Here we constructed a simplified model of a bat body with ears based upon morphological measurements of a brown long-eared bat (Plecotus auritus) to examine the aerodynamic implications of flying with large ears. The forces and moments produced by the model were measured using a sensitive 6-component force and torque balance during wind tunnel testing. The large ears of the model bat produced positive lift as well as positive drag of the same order of magnitude. At small ears angles (0° to 10°), increasing the angle of the ears resulted in an increase of the lift-to-drag ratio. At higher ear angles (> 10°) separation of the flow occurred which caused a large decrease in the lift-to-drag ratio produced. To maximise the benefit from the ears (i.e., lift-to-drag ratio) our model predicts that a horizontal free flying P. auritus should hold its ears at an approximate angle of 10°. The results of the pitching moment coefficient are inconclusive in determining if the large ears are important as flight control structures. The additional drag produced by the ears has consequences for the foraging behaviour of P. auritus with reductions in its flight speed and foraging range.

7

Structure of horizon as an orientation cue for the flight of honey bee drones to congregation areas

84%

Koeniger N., Koeniger G., Pechhacker H.

Pszczelnicze Zeszyty Naukowe

|

1998

|

tom 42

|

nr 2

8

The evolution of wing folding and flight in the Dermaptera [Insecta]

84%

Haas F.

Acta Zoologica Cracoviensia

|

2003

|

tom 46

|

nr Suppl.

The structure of the dermapteran hind wings is described and their hind wing folding is compared with other insect taxa with folded wings (i.e. Coleoptera, Hymenoptera and Blattodea). The peculiarities of the dermapteran hind wing folding are pointed out: the wings are unfolded by the cerci, one wing after the other, in a rather slow process. The antagonistic movement, folding the wings, is achieved by intrinsic elasticity and resilin. The stem group representatives of the Dermaptera, the ‘Archidermaptera’ and the ‘Protelytroptera’, both taxa probably paraphyletic, do show the step-wise transformation from a simple, unfolded, ‘cockroach’-like wing, to the complex wing of Recent Dermaptera.

9

The surface-skimming hypothesis for the evolution of insect flight

84%

Marden J. H.

Acta Zoologica Cracoviensia

|

2003

|

tom 46

|

nr Suppl.

The surface-skimming hypothesis for the evolution of insect flight poses that insects first used wings and aerodynamic locomotion to move in two dimensions across water surfaces. Here I present an overview of recent advances in our understanding of surface-skimming locomotion, and how these findings relate to phylogenetic origins of insects and developmental and anatomic origins of insect wings. Behavioral surveys show taxonomically widespread use of skimming by Plecoptera and more taxonomically restricted use of skimming by Ephemeroptera. Because these two orders arose near the root of the early split of pterygote insects into the Paleoptera and Neoptera, traits that appear in both groups are strong candidates for traits possessed by the first winged insects. Comparisons across plecopteran species show that skimming speed increases as contact with the water surface decreases, thereby providing a mechanical pathway over which directional selection may have acted to improve aerodynamic capability in early skimmers. Evolution along this route may have occurred within species in response to factors such as scramble competition and sexual selection. Phylogenetic analyses suggest that the common ancestor of modern Plecoptera was capable of both skimming and flying; such dual ability is widespread among extant stoneflies, including the most basal families. Both the mechanics and the semi-aquatic setting of skimming fit well with the growing understanding that insects and crustaceans are sister clades and that insect wings evolved from gills.

10

Scapular orientation in theropods and basal birds, and the origin of flapping flight

84%

Senter P.

Acta Palaeontologica Polonica

|

2006

|

tom 51

|

nr 2

Basal birds such as Archaeopteryx and Confuciusornis are typically portrayed as flapping fliers. However, here I show that shoulder joint orientation in these animals prevented elevation of the humerus above the dorsum, thereby preventing use of the recovery stroke, an important part of flapping flight. In members of the clade Ornithothoraces, which includes extant birds and the extinct avian clade Enantiornithes, the shoulder joint is reoriented to permit elevation of the humerus above the dorsum, permitting flapping flight. Although basal birds may have glided, flapping flight began significantly later in avian evolution than has been thought.

11

Test flights of meadow communites by Apidae insects

67%

Kaczmarek Z., Kozlowski S.

Łąkarstwo w Polsce

|

2011

|

tom 14

The performed investigations were carried out on meadow complexes situated in the region of Wielkopolska recognised for its long traditions of meadow management and bee-keeping. The results of our investigations and observations show that permanent meadows exhibit sufficient floristic diversity to make them attractive for Apidae. However, flights of Apidae to visit meadow communities in order to collect nectar vary. The attractiveness of Cirsium oleraceum communities is evidently higher than that of Alopecurus pratensis, while communities with Trifolium repens and Taraxacum officinale occupy intermediate positions. All the above-mentioned plant communities are more attractive for Apoidae than Brassica napus cultivations. In addition, visits paid to individual species of plant communities also vary. Apoidae appear to favour in particular the following plant species: Vicia cracca, Trifolium sp., Taraxacum officinale, Cirsium sp., Leontodon autumnalis, Melilotus sp., Polygonum bistorta, Euphrasia rostkoviana and Lychnis flos-cuculi. Another advantage of permanent meadows is the presence in their sward of plants which blossom during the entire period of vegetation. Therefore, if we want to enhance meadow floristic diversity, it is necessary to introduce (by oversowing) into their communities plant species which are visited by Apidae most readily. In addition, it can be concluded on the basis of the performed experiments that the Apoidae population in our region is very poor and is limited to the following little species: Apis mellifera, Bombus terrestris and B. lapidaries, B. sylvarum, B. pascuorum and Halictus sp.

12

Reconstructing insect flight performance from fossil evidence

67%

Wootton R. J.

Acta Zoologica Cracoviensia

|

2003

|

tom 46

|

nr Suppl.

Some structural characters and morphometric variables – size, body shape and proportions, wing shape and structure – that appear in insects to be linked with flight performance, are discussed and evaluated, and methods are described for deriving these from fossil material. Some wing design categories associated with particular flight techniques and capabilities are identified. Their use in reconstructing the flight performance of extinct insects is illustrated with reference to Carboniferous palaeodictyopteroids and Mesozoic palaeontinoid Hemiptera.

13

Migrations and evolution of metabolism in birds

59%

Gavrilov V. M.

The Ring

|

1994

|

tom 16

|

nr 1-2

Ograniczanie wyników

Issledovanie parametrov traektorii poleta pochatkov pri ikh otdelenii na strepernykh plastinakh

Feeding flights of the Black-headed Gull [Larus ridibundus] in the surroundings of Riga

On the skimming hypothesis of the origin of insect flight

Rudimentary finger claws in a flower-visiting phyllostomid bat

The extent of the pterosaur flight membrane

The aerodynamics of big ears in the brown long-eared bat Plecotus auritus

Structure of horizon as an orientation cue for the flight of honey bee drones to congregation areas

The evolution of wing folding and flight in the Dermaptera [Insecta]

The surface-skimming hypothesis for the evolution of insect flight

Scapular orientation in theropods and basal birds, and the origin of flapping flight

Test flights of meadow communites by Apidae insects

Reconstructing insect flight performance from fossil evidence

Migrations and evolution of metabolism in birds