Sheila Patek

Adjunct Assistant Professor
patek@berkeley.edu

Education
A.B., Harvard University, 1994

Ph.D., Duke University, 2001

Postdoctoral
Miller Postdoctoral Fellow, University of California Berkeley, 2001-2004

Research Interests

The primary goal of the research in my laboratory is to examine the dynamic interplay between evolutionary processes and basic physics. We address this issue in two broad systems –evolutionary physiology of communication in the sea and the evolutionary dynamics of fast animal movements – with most projects focusing on arthropods. Our tools range from high speed videography and acoustics to phylogenetics and physiology.

Evolutionary physiology of communication in the sea

Why do crickets sing with their forewings whereas many crabs stridulate with their claws? How have the mechanics of pick-and-file sound production influenced the signal diversity observed in shrimps, ants and grasshoppers? We examine the competing influences of form and function during evolutionary origins and subsequent evolutionary diversification. Specifically, we figure out how animals produce communication signals, and test how the physiology of these structures has influenced the evolution and diversification of animal communication. Our current focus is on spiny lobsters (Palinuridae) and we integrate four areas – physiological measurements, field research, fossil reconstruction, and physics-based computer modeling – to illuminate their acoustic behavior and physiology in the context of their long evolutionary history.

Evolutionary dynamics of fast animal movements

All animals face a single overriding constraint on their ability to produce fast movements – muscles contract slowly and over small distances. Repeatedly over evolutionary history, animals have overcome this limitation through the use of mechanical systems that decrease the duration of movement and thereby increase speed and acceleration. Many human-made mechanical systems incorporate this strategy. For example, in the crossbow, slow muscle contractions of a human arm load the bow and ultimately a latch releases the arrow. With this mechanism, the arrow accelerates and flies through the air at far greater speeds than would have been possible by simply throwing the arrow. The technical term for this process is power amplification. In animals, power amplification is achieved through a suite of structural adaptations including springs, latches, lever arms and linkages.

We examine the biomechanics and evolution of power amplification primarily in two systems – mantis shrimp (Stomatopoda) and trap jaw ants. While most studies to date have focused on solving the intriguing biomechanics of single species, notably little is known about the evolutionary processes and patterns underlying the diversification of power amplified systems. Thus, using force sensors, high speed videography, field research and phylogenetic comparative methods, we probe the origins of these remarkable structures and the interrelationship between the basic physics underlying extremely fast movements and their fantastic radiations over macro-evolutionary timescales.

Representative Publications

Patek, S.N., B. N. Nowroozi, J. E. Baio, R. L. Caldwell and A. P. Summers. 2007. Linkage mechanics and power amplification of the mantis shrimp’s raptorial strike. Journal of Experimental Biology, 210: 3677-3688.

Patek, S.N. and J.E. Baio. 2007. The acoustic mechanics of stick-slip friction in the California spiny lobster (Panulirus interruptus). Journal of Experimental Biology, 210: 3538-3546.

Patek, S.N., J.E. Baio, B. L. Fisher, and A. V. Suarez. 2006. Multifunctionality and mechanical origins: ballistic jaw propulsion in trap-jaw ants. Proceedings of the National Academy of Sciences, 104(34): 12787-12792.

Patek, S.N. and R. L. Caldwell. 2006. The stomatopod rumble: sound production in Hemisquilla californiensis. Marine and Freshwater Behaviour and Physiology, 39(2): 99-111.

Patek, S.N. and R. L. Caldwell. 2005. Extreme impact and cavitation forces of a biological hammer: strike forces of the peacock mantis shrimp (Odontodactylus scyllarus). Journal of Experimental Biology, 208: 3655-3664.

Patek, S.N., W.L. Korff and R.L. Caldwell. 2004. Deadly strike mechanism of a mantis shrimp. Nature, 428: 819-820.

Patek, S.N. and T.H. Oakley. 2003. Comparative tests of evolutionary tradeoffs in a palinurid lobster acoustic system. Evolution, 57(9): 2082-2100.

Patek, S.N. 2002. Squeaking with a sliding joint: mechanics and motor control of sound production in spiny lobsters. Journal of Experimental Biology, 205: 2375-2385.

Patek, S.N. 2001. Spiny lobsters stick and slip to make sound. Nature, 411: 153-154.

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