Birds are a diverse group of vertebrates, with over 10,000 extant species. Diversification into volant, aquatic and terrestrial environmental niches has precipitated a remarkable morphological diversity between species. Birds have a unique respiratory system consisting of a rigid lung connected to an air sac system. Air is pumped into the respiratory system via movements of the ribcage and sternum. Previous research identified the uncinate processes, ossified projections extending from the vertebral ribs, as critical respiratory and locomotor structures. Uncinate processes facilitate inspiration and expiration through associated muscles that displace the ribs and therefore sternum. External intercostal muscles project from the processes and function during locomotion to stabilise body roll. Therefore uncinate processes provide a link between breathing and locomotion in birds. The objective of my PhD is to extend beyond this basic research on uncinate processes to investigate how diversity in avian body morphology relates to the fundamental functions of breathing and locomotion.While the function of uncinate processes in respiration has been identified, the mechanism whereby ventilatory movements are elicited is not known. Therefore I present a model that demonstrates how respiratory movements of the skeleton are facilitated by the lever action of uncinate processes. Furthermore, variation in process and sternal morphology is driven by adaptation to different forms of locomotion. Therefore fundamental differences in breathing mechanics may be associated with specialisation to locomotor behaviour. Detailed developmental studies of the uncinate processes in birds are almost nonexistent. I provide the first detailed description of developmental changes in the uncinate processes in the turkey. Ossification of the uncinate processes begins around the time of hatch. However, the base is cartilaginous upon hatching and so the lever action of the processes may be compromised in the chick. I provide further evidence for a functional link between process length and respiratory physiology, since elongated processes support an elevated resting metabolic rate in birds. This link was further explored in physiological experiments where the energetic cost of walking in the barnacle goose was manipulated by load carrying. Carrying extra mass on the sternum is more energetically costly than an equivalent back load indicating that the cost of breathing increased. A directly proportional relationship exists between increasing mass of back load and metabolic rate, while sternal loads were approximately twice as expensive to carry during locomotion. Leg loads incurred the greatest increase in metabolism. Finally, I demonstrate how uncinate processes functioned as respiratory structures in basal avian species and a theropod ancestor of modern birds. Development of the uncinate processes may have been an important step in the evolution of the avian lung - air sac system.The principal findings of the five first author research articles presented in this PhD thesis shed important new light on the ventilatory mechanics in birds and highlight interactions between breathing and locomotion. Diversity in avian body morphology driven by adaptation to various locomotor behaviours has resulted in modification of the respiratory system.

I have collected a series of linear measurements of the postcranial skeletons of 43 extant crocodylian and lepidosaur taxa to determine if those engaging in similar locomotor behavior display similar morphology despite phylogenetic differences. Stepwise discriminant function analyses reveal reptile locomotor mode can be accurately predicted (over 80% correct) based on morphology. Semi-aquatic taxa are distinguished by a longer ischium relative to pubis length, a longer scapula relative to humerus length, and a broader acetabulum than terrestrial and arboreal taxa. Arboreal taxa display a more elongate, gracile humerus and a smaller acetabulum. This morphometric data can potentially be used to predict the locomotor behavior of a wide range of extinct reptile taxa. Within this study, Hyposaurus rogersii, Necrosuchus ionensis, Alligator sp. of the Gray Fossil Site, Crocodylus affinis, and Allognathosuchus mooki were examined and all were inferred to be semi-aquatic by the discriminant function analysis.

El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / This paper presents an alternative solution to improve the locomotion system of a hexapod robot by artificial intelligence. Through an optimal design to achieve static stability, dynamic stability and optimize energy consumption through an autonomous system that is able to perform trajectories without any inconvenience. For the robot to move without flaws has certain restrictions in design (weight, size, materials, etc.) The hexapod has a high degree of movement and this allows many trajectories handle at the time of travel. Using sensors under certain working conditions we will obtain the necessary data and signals to satisfactorily comply with the hexapod robot design. / Revisión por pares

Locomotion is central to the survival of many animal species; however large variation in performance, for example in speed or endurance, exists between individuals within a species. Using the bumblebee species, Bombus impatiens, I studied the extent of the variation in several flight performance traits and how they are associated. I first addressed how bumblebee workers vary in foraging effort and observed that only around half of the monitored individuals underwent foraging activity. Additionally, significant variation in metabolic rate between foragers and non-foragers was uncovered. I further investigated if such variation could be associated with flight performance capacity, such as an individual’s ability to carry a load, their flight speed and distance traveled, their wing morphology and kinematics, and their flight metabolic rate. These traits are commonly measured to characterize flight capacity in insects, however the links between them have yet to be investigated. Links between morphology, wing kinematics and peak metabolic rate previously uncovered in the literature were observed in my analysis, although variation in their scaling with body mass was detected. Vertical force scaled isometrically with body mass but was not related to it when expressed in on a mass specific basis (VF m-1g-1, where m is gravitation acceleration). In regard to forward flight speed, body mass does have an affect, however it alone does not have a great degree of explanatory power and other factors such as morphology and wing kinematics are likely to play a greater part in its determination. Finally, maximum flight speed had a significant relationship with total flight time. Together, these results demonstrate that some links do exist between flight performance traits, however links are not present between all traits and certain flight performance traits should be treated as independent of each other.

Natural terrain constantly challenges locomotor stability. Bipedal parasagittal runners rely on proximo-distal control mechanisms and passive mechanical mechanisms to rapidly adjust to changing environments. However, it is not known how sprawled bipedal runners, like the basilisk lizard, adjust to unexpected perturbations. This study examines how basilisks navigate visible drop perturbations to elucidate the control strategies used to maintain stability. We ran four basilisk lizards along a 2.7 m long trackway with an embedded 6-d.o.f. force plate. Control trials were recorded with the force plate mounted flush to the track surface. We lowered the plate to 40% of the lizards’ limb length, relative to the track surface, for perturbation trials. We hypothesized that much like parasagittal runners, basilisks would rely on three distinct compensatory mechanisms to convert the potential energy (PE) change from the drop into fore-aft and vertical kinetic energy (KE) or to increase the total energy of the system (Ecom), as well as a fourth potential mechanism converting PE into medio-lateral KE, as a result of their sprawled limb posture. On average, lizards ran slower (T-ratio30=2.548, p = 0.0162) and with a more vertical limb posture (T-ratio28=-6.119, p < 0.0001) during the drop perturbation. As expected, vertical KE increased in drop surface trials. However, contrary to our hypothesis, the drop perturbation appeared to have little detectable effect on fore-aft and medio-lateral KE. Preliminarily, these results suggest that the sprawled limb posture may afford increased robustness to perturbations such as a sudden drop in surface height, facilitating kinematic compensations independent of significant kinetic changes. / Kinesiology

This thesis describes the use of a micropipette deflection technique to measure the viscous forces experienced by the millimeter sized undulatory swimmer and model organism C. elegans. Using a specialized pipette, we are able to simultaneously measure both the lateral and propulsive forces acting on the worm. We find that the measured force curves are well described by Resistive Force Theory, which is a low Reynolds number hydrodynamic model. This work constitutes the first justification of its applicability at Reynolds numbers of this magnitude (roughly 0.1). Through our comparison with Resistive Force Theory, we extract the worm's drag coefficients, which are in agreement with an existing theoretical prediction. Through a simple scaling argument, we obtain a relationship between the size of the worm and the typical viscous forces, which is in good agreement with our data. We also present a study aimed at measuring how the hydrodynamic forces on the worm change in proximity to solid boundaries. Using micropipette deflection, forces are measured at controlled distances from a single planar boundary and midway in between two parallel boundaries. We find the viscous forces and drag coefficients to increase significantly as the worm approaches a boundary. We find a constant value for the ratio of normal to tangential drag coefficients at all distances from a single boundary, but measure it to increase significantly as the worm is confined between two boundaries. In addition, the worm is seen to undergo a continuous gait modulation, primarily characterized by a decreased swimming amplitude, as it is subject to larger drag forces in confinement. Finally, the interactions between two worms swimming nearby one another are probed. Worms are held adjacent to one another using micropipettes, and are found to tangle with each other, rather than interact hydrodynamically. We develop simple models that well capture the onset and probability of tangles as a function of the separation distance between the worms. / Thesis / Master of Science (MSc)

Several indicators of animal welfare were measured to determine the impact of relocation on lactating dairy cows. In experiment one, locomotion was scored on a 4-point scale where 1 = normal and 4 = lame. Cleanliness was scored on a 4-point scale where 1 = little or no manure visible and 4 = heavy plaques of manure on 3 body regions: udder, lower leg, and flank/upper leg. In experiment two, milking parlor behaviors observed were cow reactivity (REACT), latency to enter the parlor (LAT), and plasma cortisol (CORT). REACT was evaluated on a numeric scale (0 = ideal milker to 3 = steps and kicks frequently) to define behavior during udder preparation, claw fitting, and milking. LAT was the time necessary for each cow to enter the milking parlor. In these studies, the effects of treatment or breed on MY, lameness, parlor behaviors, stress, and cow cleanliness were monitored. In experiment one, cows with access to a rubber mat in front of the feed bunk had lower locomotion scores and cleaner lower legs. There were no breed effects on locomotion, but Jerseys had cleaner lower legs than Holsteins. The effect of the new facility on locomotion occurred gradually. Cows with higher locomotion scores had decreased milk production, but the results were not significant. In experiment two, relocation caused an increase in plasma cortisol and LAT. Milk yield decreased the p.m. on the day of relocation, but overall milk yield was not affected. Jerseys had lower plasma cortisol levels and latency to enter the parlor, but had a greater decline in p.m. milk yield the day of relocation. In conclusion, alternative flooring may alleviate some locomotion problems caused by relocation to a new facility. Additionally, moving to a new facility may have an effect on behavior and stress, but these effects are short-lived and effects on overall milk production minimal. / Master of Science

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