General Research Interests
My lab focuses on the origin and evolution of innovations, integration, and complexity, with a strong emphasis on the ecological context of organismal function. To do this, we integrate biomechanics, comparative evolutionary methods, comparative physiology, and ecology. This naturally combines organismal approaches with sophisticated laboratory techniques (see below). Examples include the functional and evolutionary consequences of gaining and losing adhesion among geckos, the integration of feeding and locomotion among fishes and snakes, the neuromuscular basis of locomotion among anoles and geckos, the dynamics of tail autotomy among geckos, and the role of vision in gecko locomotion. Our fieldwork is conducted in a number of places, including the Bamfield Marine Sciences Centre in British Columbia, Gobabeb in Namibia, South Africa, Nouragues in French Guiana, and Trinidad & Tobago.
Examples of recent research projects:
- Biomechanics and the origin of species: predator-prey interactions in fishes (see publication 66)
- The morphology and ecology of the adhesive apparatus of geckos (see publications 52 & 57)
- Muscle dynamics and biomechanics of locomotion among Anolis lizards (see publications 36 & 42)
- The biomechanics and evolution of gecko locomotion (see publications 48, 52, & 53)
- The ecomechanics and integration of locomotion and feeding in fishes (see publications 58-60)
- Functional complexity within and among muscles during locomotion (see publications 28-29)
- The neurobiology and biomechanics of tail autotomy in lizards (see publications 40 & 49)
- Hydrodynamics and biomechanics of suction feeding in fishes (see publications 55 & 59)
- Electromyography (EMG): This technique allows one to measure the electrical activity in a muscle using indwelling electrodes. I use this to quantify the intensity and timing of activation patterns during dynamic locomotion
- Sonomicrometry: This technique utilizes ultrasonic pulses between piezoelectric crystals to measure distances in real time. For example, I implant these into muscles to measure the changes in length along a fascicle.
- Aurora in situ/in vitro muscle lever system: I use this system to examine force-length and force-velocity properties of muscles. By combining this with in vivo measurements, I am able to determine how muscles operate in relation to their capabilities.
- Digital particle image velocimetry (DPIV): This is a modern computational technique that permits the visualization of fluid movement. I use this to determine flow patterns during suction feeding in fishes.
- High-speed digital video: I use a pair of Photron APX-RS cameras, a pair of Phantom Miro M110 cameras (capable of filming 250,000 images/second), and a pair of Edgertronic cameras (sensitive to IR) to quantify three-dimensional high-speed movements during locomotion and prey capture.
- In vivo pressure recordings: By surgically implanting pressure transducers into the mouth (buccal) cavities of fishes, I quantify the pressure within the buccal cavity relative to the surrounding fluid during suction feeding in fishes.
- Force plates: I use a custom built force plate (from 6 axis force-torque sensors) to quantify the mechanics of terrestrial locomotion in birds and lizards. This involves inverse dynamics and center of mass mechanics, and I study animals from 3kg down to 2g.