Thursday, March 16, 2015 AGS Luncheon
"A Spring in the Dinosaur's Step: Musculoskeletal
Noon Luncheon 11:30-1:00 pm
Investigating the relative running ability of extinct animals can be approached through the analysis of skeletal (ostelological) adaptations for running, or cursoriality. This approach suits dinosaurs particularly well, since skeletal evidence is what fossils tend to provide best. Soft-tissue aspects of dinosaurs such as metabolism and muscle structure impact heavily upon the animals' potential cursorial ability, but to take these factors into account relies upon many assumptions and a great deal of speculation. In comparison, osteological analysis has the advantage of dealing with hard and quantifiable evidence. Dinosaurs, like many vertebrates, would have had the capability to walk, run and probably even skip! The relative positions of body, limbs, centre of mass, and speed combine to define gait: walking, jogging, trotting, running, and galloping. Each mode of locomotion has its own specific gait pattern. Animals adjust their gait to minimize energy expenditure, whether walking, hopping, or running.
As the use of computer modeling becomes more widespread in palaeontology, and precise laser-scanned models of dinosaur skeletons become more widely available, increases in computing power are making greater and greater use of elaborately fleshed-out digital dinosaurs to investigate movement and locomotion. Software (Gaitsym) has been developed at the University of Manchester that allows the gait of both extant and extinct animal to be derived through using a distributed genetic algorithm optimization system. This approach employs a genome that represents the gait cycle duration and the muscle activation levels at given time periods through a gait cycle. I use the word genome here cautiously, since this suggests an evolutionary or even biological process occurs where the computer 'learns'. This is not the case. The 3D functional space that a limb could potentially move in is quite large, but is unlikely an organism uses much of that potential space. Animals tend to work in the most efficient way to get from A to B for their specific body plan, geometry, the environment they are in, and what they are doing (hunting, breeding, or browsing). Gaitsym searches for the most efficient way from getting from A to B for each musculoskeletal model that we create. After hundreds of thousands of virtual 'runs', more efficient gaits for each model are generated. The software doesn't so muchlearn from its mistakes, but simply builds upon them.
The optimization of musculoskeletal dinosaur models has taken a curious step forward, a step that relies upon the potential of stored energy in elastic structures. The potential elastic properties of the backs of dinosaurs have fascinated scientists for some time, with vast tendons often preserved along the top and side of vertebrae. The locomotor capabilities of quadrupedal vertebrates are considerably enhanced by the storage and recoil of elastic energy in back tendons, providing energy recovery from step to step. However, elastic recoil in living bipeds, such as running humans, is restricted to the legs and feet due to a vertical orientation of the torso. We used a reverse-engineering approach to
Phil Manning is Professor of Natural History and Director of the cross-faculty InterdisciplinaryCentre for Ancient Life (ICAL) at the University of Manchester (UK). Phil is also a Fellow (International) of the Explorer's Club (New York). He has a BSc from Leicester University in Earth Sciences, an MSc from the University of Manchester in Geology and a PhD from the University of Sheffield in Paleontology.
Phil has worked as a paleontologist for over 25 years, including positions in museums and universities, working in both the laboratory and the field. A pivotal theme of his research is the study the multiple contemporary problems of natural-resource conservation and environmental quality and how they relate to the history of life on Earth. His work explores both the past and present interactions of processes that integrate the four terrestrial spheres: lithosphere, hydrosphere, atmosphere and biosphere. Phil's
Phil has presented several documentaries including a recent series for National Geographic Channel ('Jurassic CSI') that showcased the application of new technologies in paleontology and he has also contributed to many BBC, Discovery Channel, Channel 4 and History Channel TV documentaries. Phil plays an active role in the University of Manchester's public programs, contributing to open-days, public lectures, workshops and fieldwork. He has authored both children and popular science books and is a regular contributor to public speaking programs around the world, promoting the public engagement of science. Phil has been appointed as the Science and Technology Research Council (STFC) Science in Society Fellow (2013-2017), so as to further promote science and technology to as wide an audience
The 'Dinosaur CSI' blog is authored and regularly updated by Phil and includes information on recent publications from ICAL as well as their extensive field programs around the globe. You can follow Phil on Twitter @DrPhilManning