scholarly journals The Allometry of Morphology in Flora and Fauna of New Zealand and Offshore Islands

2021 ◽  
Author(s):  
Carl Woodhams
Keyword(s):  
Allometric Scaling ◽  
Wing Length ◽  
Major Axis ◽  
Muscle Size ◽  
Island Rule ◽  
Wing Loading ◽  
Island Species ◽  
Rate Of Increase ◽  
Loading Ratio ◽  
Primary Form

<p>Flight is the primary form of locomotion for many avian species and is enabled by allometric scaling of morphological features such as wingspan, flight muscle size, and bone tensile strength. Contrary to this, the evolution of flightlessness in birds displays a selection towards an increase in body size with a reduction in flight associated features. The aim of this chapter is to explore the Loss of Dispersibility hypothesis as a cause for flightlessness in island birds, with consideration of the Island Rule and the Size-Constraint hypothesis. With island species paired with closest mainland relatives, comparative analyses were conducted comparing the change in wing loading ratios, wing lengths, and mass. With paired t-tests and Major Axis linear regression modelling, the hypotheses of isometric or allometric scaling in each of the features were tested. An increase in wing-loading ratio was apparent for many island species, as well as an increase in both mass and wing length. However, the rate of increase between mass and wing length is disproportionate, with mass increasing at a greater rate than wing length. These trends reject the Loss of Dispersibility hypothesis in support of the Size-Constraint hypothesis while providing little evidence for the Island Rule.</p>

scholarly journals The Allometry of Morphology in Flora and Fauna of New Zealand and Offshore Islands

2021 ◽  
Author(s):  
Carl Woodhams
Keyword(s):  
Allometric Scaling ◽  
Wing Length ◽  
Major Axis ◽  
Muscle Size ◽  
Island Rule ◽  
Wing Loading ◽  
Island Species ◽  
Rate Of Increase ◽  
Loading Ratio ◽  
Primary Form

<p>Flight is the primary form of locomotion for many avian species and is enabled by allometric scaling of morphological features such as wingspan, flight muscle size, and bone tensile strength. Contrary to this, the evolution of flightlessness in birds displays a selection towards an increase in body size with a reduction in flight associated features. The aim of this chapter is to explore the Loss of Dispersibility hypothesis as a cause for flightlessness in island birds, with consideration of the Island Rule and the Size-Constraint hypothesis. With island species paired with closest mainland relatives, comparative analyses were conducted comparing the change in wing loading ratios, wing lengths, and mass. With paired t-tests and Major Axis linear regression modelling, the hypotheses of isometric or allometric scaling in each of the features were tested. An increase in wing-loading ratio was apparent for many island species, as well as an increase in both mass and wing length. However, the rate of increase between mass and wing length is disproportionate, with mass increasing at a greater rate than wing length. These trends reject the Loss of Dispersibility hypothesis in support of the Size-Constraint hypothesis while providing little evidence for the Island Rule.</p>

Comparison of the Flame Characteristics of Turbulent Circular and Elliptic Jets in a Crossflow

2002 ◽  
Vol 124 (3) ◽  
pp. 197-203 ◽  
Author(s):  
S. R. Gollahalli ◽  
D. Pardiwalla
Keyword(s):  
Flame Structure ◽  
Flux Ratio ◽  
Major Axis ◽  
Minor Axis ◽  
No Production ◽  
Sampling System ◽  
Computer Data ◽  
Rate Of Increase ◽  
Jet Velocity ◽  
Lower Limits

This study was directed to understand the coupling effects of the noncircular geometry of the burner and a crossflow on the combustion of gas jets. This paper compares the characteristics of turbulent propane jet flames from circular (diameter=0.45 cm) and elliptic (major axis/minor axis=3) burners of equivalent exit area in a crossflow. The elliptic burner was oriented with its major axis or minor axis aligned with the crossflow. Experiments were conducted in a wind tunnel provided with optical and probe access and capable of wind speeds up to 12.5 m/s. The burners were fabricated with metal tubes. Instrumentation included a Pt-Pt/13% Rh thermocouple, a quartz-probe gas sampling system, chemiluminescent and nondispersive infrared analyzers, a video-recorder, and a computer data acquisition system. The measurements consisted of the upper and lower limits of jet velocity for a stable flame, flame configuration, and visible length. Flame structure data including temperature profiles and concentration profiles of CO2,O2, CO, and NO were obtained in a two-zone flame configuration (at jet to crossflow momentum flux ratio=0.11), where a planar recirculation exists in the wake of the burner tube followed by an axisymmetric tail. The relative emission indicators of CO and NO were estimated from the composition data. Results show that the upper and lower limits of the fuel jet velocity increase with the crossflow velocity for all burners, and the rate of increase is highest for the elliptic burner with its minor axis aligned with the crossflow. That burner configuration also produces the longest flame. The relative emission indicators show that the CO production is lower and NO production is higher with elliptic burners than with circular burners in crossflow.

scholarly journals Is there tree senescence? The fecundity evidence

2021 ◽  
Vol 118 (34) ◽  
pp. e2106130118
Author(s):  
Tong Qiu ◽  
Marie-Claire Aravena ◽  
Robert Andrus ◽  
Davide Ascoli ◽  
Yves Bergeron ◽  
...  
Keyword(s):  
Strong Evidence ◽  
Regression Models ◽  
Forest Regeneration ◽  
Allometric Scaling ◽  
Dynamic Models ◽  
Crown Architecture ◽  
Tree Diameter ◽  
Architectural Change ◽  
Rate Of Increase ◽  
Large Trees

Despite its importance for forest regeneration, food webs, and human economies, changes in tree fecundity with tree size and age remain largely unknown. The allometric increase with tree diameter assumed in ecological models would substantially overestimate seed contributions from large trees if fecundity eventually declines with size. Current estimates are dominated by overrepresentation of small trees in regression models. We combined global fecundity data, including a substantial representation of large trees. We compared size–fecundity relationships against traditional allometric scaling with diameter and two models based on crown architecture. All allometric models fail to describe the declining rate of increase in fecundity with diameter found for 80% of 597 species in our analysis. The strong evidence of declining fecundity, beyond what can be explained by crown architectural change, is consistent with physiological decline. A downward revision of projected fecundity of large trees can improve the next generation of forest dynamic models.

Comparison of the Flame Characteristics of Circular and Elliptic Jets in a Cross-Flow

2000 ◽  
Author(s):  
S. R. Gollahalli ◽  
D. Pardiwalla
Keyword(s):  
Cross Flow ◽  
Major Axis ◽  
Minor Axis ◽  
No Production ◽  
Sampling System ◽  
Computer Data ◽  
Rate Of Increase ◽  
Jet Velocity ◽  
The Cross ◽  
Lower Limits

Abstract This study was directed to understand the coupling effects of the noncircular geometry of the burner and a cross-flow on the combustion of gas jets. This paper compares the characteristics of propane jet flames from circular (diameter = 0.45 cm) and elliptic (major axis = 0.75 cm, minor axis = 0.26 cm) burners of equivalent exit area in a cross-flow. The elliptic burner was oriented with its major axis or minor axis aligned with the cross-flow. Experiments were conducted in a wind-tunnel provided with optical and probe access and capable of wind speeds up to 12.5 m/s. The burners were fabricated with metal tubes. Instrumentation included a Pt-Pt/13%Rh thermocouple, a quartz-probe gas sampling system, chemiluminescent and non-dispersive infrared analyzers, a video-recorder, and a computer data acquisition system. The measurements consisted of the upper and lower limits of jet velocity for a stable flame, flame configuration, and visible length. Flame structure data including temperature profiles and concentration profiles of CO2, O2, CO, and NO were obtained in a two-zone flame configuration where a planar recirculation exists in the wake of the burner tube followed by an axisymmetric tail. Emission indices of CO and NO were estimated from the composition data. Results indicate that the upper and lower limits of the fuel jet velocity increase with the cross-flow velocity for all burners, and the rate of increase is highest for the elliptic burner with its minor axis aligned with the cross-flow. That burner configuration also produces the longest flame. The emission indices show that the CO production is lower and NO production is higher for elliptic burners than for circular burners in cross-flow. Also, aligning the minor axis of the elliptic burner with the cross-stream is superior in terms of flame stability and emissions of NO and CO.

Reduced major axis regression and the island rule

2007 ◽  
Vol 34 (11) ◽  
pp. 1998-1999 ◽  
Author(s):  
Trevor D. Price ◽  
Albert B. Phillimore
Keyword(s):  
Major Axis ◽  
Island Rule ◽  
Reduced Major Axis

scholarly journals Predictable evolution toward flightlessness in volant island birds

2016 ◽  
Vol 113 (17) ◽  
pp. 4765-4770 ◽  
Author(s):  
Natalie A. Wright ◽  
David W. Steadman ◽  
Christopher C. Witt
Keyword(s):  
Convergent Evolution ◽  
Bird Species ◽  
Small Island ◽  
Island Rule ◽  
Drastic Reduction ◽  
General Applicability ◽  
Bird Populations ◽  
Island Species ◽  
Mammalian Predators ◽  
Flight Muscles

Birds are prolific colonists of islands, where they readily evolve distinct forms. Identifying predictable, directional patterns of evolutionary change in island birds, however, has proved challenging. The “island rule” predicts that island species evolve toward intermediate sizes, but its general applicability to birds is questionable. However, convergent evolution has clearly occurred in the island bird lineages that have undergone transitions to secondary flightlessness, a process involving drastic reduction of the flight muscles and enlargement of the hindlimbs. Here, we investigated whether volant island bird populations tend to change shape in a way that converges subtly on the flightless form. We found that island bird species have evolved smaller flight muscles than their continental relatives. Furthermore, in 366 populations of Caribbean and Pacific birds, smaller flight muscles and longer legs evolved in response to increasing insularity and, strikingly, the scarcity of avian and mammalian predators. On smaller islands with fewer predators, birds exhibited shifts in investment from forelimbs to hindlimbs that were qualitatively similar to anatomical rearrangements observed in flightless birds. These findings suggest that island bird populations tend to evolve on a trajectory toward flightlessness, even if most remain volant. This pattern was consistent across nine families and four orders that vary in lifestyle, foraging behavior, flight style, and body size. These predictable shifts in avian morphology may reduce the physical capacity for escape via flight and diminish the potential for small-island taxa to diversify via dispersal.

scholarly journals Measuring Intraspecific Variation in Flight-Related Morphology of Monarch Butterflies (Danaus plexippus): Which Sex Has the Best Flying Gear?

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Andrew K. Davis ◽  
Michael T. Holden
Keyword(s):  
Flight Muscle ◽  
Danaus Plexippus ◽  
Structural Features ◽  
Flight Behavior ◽  
Muscle Size ◽  
Body Parts ◽  
Wing Loading ◽  
Long Distance ◽  
Lepidopteran Species ◽  
Individual Body

Optimal flight in butterflies depends on structural features of the wings and body, including wing size, flight muscle size, and wing loading. Arguably, there is no butterfly for which flight is more important than the monarch (Danaus plexippus), which undergoes long-distance migrations in North America. We examined morphological features of monarchs that would explain the apparent higher migratory success and flight ability of females over males. We examined 47 male and 45 female monarch specimens from a project where monarchs were reared under uniform conditions. We weighed individual body parts, including the thorax (flight muscle) and wings, and computed wing loading and wing thickness for all specimens. When we compared each morphological trait between sexes, we found that females did not differ from males in terms of relative thorax (wing muscle) size. Females were generally smaller than males, but females had relatively thicker wings than males for their size, which suggests greater mechanical strength. Importantly, females had significantly lower wing loading than males (7% lower). This would translate to more efficient flight, which may explain their higher migratory success. Results of this work should be useful for interpreting flight behavior and/or migration success in this and other Lepidopteran species.

Phylogenetic comparative methods reveal higher wing loading in ant-attended Tuberculatus aphids (Hemiptera: Aphididae)

2011 ◽  
Vol 143 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Izumi Yao
Keyword(s):  
Phylogenetic Trees ◽  
Nadh Dehydrogenase ◽  
Body Volume ◽  
Phylogenetic Comparative Methods ◽  
Neighbor Joining ◽  
Wing Loading ◽  
Nadh Dehydrogenase Subunit ◽  
Wing Area ◽  
Bayesian Analyses ◽  
Loading Ratio

AbstractAphids of the genus Tuberculatus Mordvilko feed on Fagaceae trees and exhibit various interactions with ants, ranging from non-attendance to intermediate or close associations. Despite possession of fully developed wings, two ant-attended species, Tuberculatus quercicola (Matsumura) and Tuberculatus sp. A, exhibited extremely low dispersal. I examined the correlation between wing loading (ratio of body volume to wing area) and ant associations in 20 species of Tuberculatus. Based on a 1317 bp sequence in two mitochondrial regions, cytochrome oxidase I (COI) and NADH dehydrogenase subunit 1 (ND1), phylogenetic trees were reconstructed by neighbor-joining (NJ), most parsimony (MP), maximum likelihood (ML), and Bayesian analyses. All phylogenetic trees showed that mutualistic interactions with ants have evolved in Tuberculatus at least five times. Comparative analyses based on the NJ, MP, and ML trees showed that increase in wing loading is correlated with ant associations, suggesting that ant-attended aphids have allocated more resources to their bodies than to their wings, resulting in lowered dispersal.

scholarly journals FLIGHT PHYSIOLOGY OF NEOTROPICAL BUTTERFLIES: ALLOMETRY OF AIRSPEEDS DURING NATURAL FREE FLIGHT

1994 ◽  
Vol 191 (1) ◽  
pp. 125-139 ◽  
Author(s):  
R Dudley ◽  
R Srygley
Keyword(s):  
Body Mass ◽  
Wing Length ◽  
Correlation Coefficients ◽  
Flight Speed ◽  
Morphological Data ◽  
Free Flight ◽  
Wing Loading ◽  
Natural Conditions ◽  
Wing Area ◽  
Wing Aspect Ratio

Airspeed measurements during natural free flight were made on a total of 270 neotropical butterflies representing 62 species. Morphological data were obtained from the same individuals for which airspeeds had been determined. Flight speed was positively correlated with body mass, thoracic mass and wing loading. Controlling for body mass, higher wing loadings were correlated with increased flight speed. Flight speed and wing aspect ratio were negatively correlated. No consistent correlations were found between airspeed and wing length, wing area or body length. Released butterflies and butterflies encountered in natural free flight did not differ substantially in flight speed allometry. The observed scaling of flight speeds was similar to that derived for a much smaller sample of butterflies flying in an insectary, although absolute values of flight speed were approximately three times higher in natural flight and correlation coefficients of allometric regressions were typically lower. These results suggest that butterfly airspeeds under natural conditions can reasonably be predicted from morphological measurements, and that studying flight in enclosed spaces preserves the allometry of flight speeds.

Detection and Characterization of earth-like Planets

1997 ◽  
Vol 161 ◽  
pp. 299-311 ◽  
Author(s):  
Jean Marie Mariotti ◽  
Alain Léger ◽  
Bertrand Mennesson ◽  
Marc Ollivier
Keyword(s):  
Direct Detection ◽  
Contrast Ratio ◽  
Angular Size ◽  
Physical Nature ◽  
Major Axis ◽  
Infrared Emission ◽  
Space Technology ◽  
Semi Major Axis ◽  
Earth Like Planets ◽  
Visible Wavelengths

AbstractIndirect methods of detection of exo-planets (by radial velocity, astrometry, occultations,...) have revealed recently the first cases of exo-planets, and will in the near future expand our knowledge of these systems. They will provide statistical informations on the dynamical parameters: semi-major axis, eccentricities, inclinations,... But the physical nature of these planets will remain mostly unknown. Only for the larger ones (exo-Jupiters), an estimate of the mass will be accessible. To characterize in more details Earth-like exo-planets, direct detection (i.e., direct observation of photons from the planet) is required. This is a much more challenging observational program. The exo-planets are extremely faint with respect to their star: the contrast ratio is about 10−10at visible wavelengths. Also the angular size of the apparent orbit is small, typically 0.1 second of arc. While the first point calls for observations in the infrared (where the contrast goes up to 10−7) and with a coronograph, the latter implies using an interferometer. Several space projects combining these techniques have been recently proposed. They aim at surveying a few hundreds of nearby single solar-like stars in search for Earth-like planets, and at performing a low resolution spectroscopic analysis of their infrared emission in order to reveal the presence in the atmosphere of the planet of CO H2O and O3. The latter is a good tracer of the presence of oxygen which could be, like on our Earth, released by biological activity. Although extremely ambitious, these projects could be realized using space technology either already available or in development for others missions. They could be built and launched during the first decades on the next century.

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