B.Sc.. University of Toronto, Toronto, Ontario, Canada 1983
Ph.D. Duke University, Durham, N. Carolina, USA, 1988
Biomechanics, functional morphology and ecophysiology of marine invertebrates and algae; mechanisms and modeling of growth and aquaculture in sea urchins, scaling of metabolic rate, effects of temperature on growth, underwater walking, and catch connective tissue in echinoderms.
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This demonstration allows the user to manipulate the value of physically important variables in the system and the output is the motion of a pendulum as defined by the angular position of the pendulum bob relative to vertical.
The damped pendulum model is programmed in Mathematica by Olaf Ellers and is based on the math published by others in the following paper:
Neill D, Livelybrooks D & Donnelly R (2007). A pendulum experiment on added mass and the principle of equivalence. Am. J. Phys. 75(3): 226-229.
Neill et al. also provides an experimental test of the calculations.
Academic Spotlight: Coastal Studies Span Walking Crabs and Artful Tourists
Summer Research at Bowdoin: Researchers Develop 'Bar Code' for Sea Urchins
Academic Spotlight: Bowdoin Researchers Seek Methods to Spur Sea Urchin Growth
Ellers, O., Yoshimura, K., Motokawa, T., Johnson, A.S. A Froude number for underwater walking. To be submitted to Biology Letters.
Johnson, A.S., *Salyers J.M., *Alcorn N.J., Ellers, O, Allen, J. (to be submitted, November, 2012). Externally visible fluorochrome marks on growing urchins. Invert. Biol.
*Pfister, A. Johnson, A., Ellers, O., Horch, H.W. (2012). Quantification of dendritic and axonal growth after injury to the auditory system of the adult cricket Gryllus bimaculatus. Front. Physio. 3:367. doi: 10.3389/fphys.2012.00367
Ellers, O., Johnson, A.S. 2009. Polyfluorochrome marking slows growth only during the marking month in the green sea urchin Strongylocentrotus droebachiensis. Invert. Biol. DOI:10.1111/j.1744-7410.2008.00159.x. Link to abstract
Selden, R.*, Johnson, A.S., Ellers, O. 2009. Crab scent induces thicker skeletons, smaller gonads and size-specific growth responses in sea urchins. Mar. Biol. 156:1057-1071 DOI : 10.1007/s00227-009-1150-0. Link to pdf
Johnson, A.S., Ellers, O., Lemire, J.*, Minor, M.*, Leddy, H.* 2002. Sutural loosening and skeletal flexibility during growth: determination of drop-like shapes in sea urchins. Proc. R. Soc. Lond. B, 269: 215-220. Link to pdf
Ellers, O. 2001. Size matters. Book Review of Scaling in Biology, J.H. Brown and G.B. West eds. Oxford Univ. Press. Complexity 6(4): 23-26. Link to issue
Ellers, O. 2000. Orientation to, and acoustic detection of, beach waves during swash-riding and migration of donacid clams and other sandy beach invertebrates. Pp. 177-194, In Biomechanics and Behaviour, P. Domenici & B. Blake (eds.). publ. BIOS., Oxford. Link to book description
Hui, C.A. & O. Ellers. 1999. Effect of high aluminum consumption on mechanics and composition of furculae of free-ranging coots. Environmental Toxicology and Chemistry 18: 970-975. Link to abstract
Ellers, O, Johnson, A.S., Moberg, P. 1998. Sutural strengthening of urchin skeletons by collagenous sutural ligaments. Biological Bulletin 195: 136-144. Link to abstract
Ellers, O. 1998. Swash-riding in the clam, Donax variabilis. McGraw-Hill 1998 Yearbook of Science and Technology, 31- 32. Link to book
Telford, M. and O. Ellers. 1998. The moving teeth of echinoids. Pp. 843-848, In Echinoderms: San Francisco, R. Mooi and M. Telford (eds.). publ. Balkema, Rotterdam.
Telford, M. & Ellers, O. 1997. Tooth advancement muscles in the sand dollar, Echinarachnius parma. Invertebrate Biology 116: 255-261. Link to abstract
Ellers, O. & Telford, M. 1997. Muscles advance the teeth in sand dollars and other sea urchins. Proc. R. Soc. Lond. B 264: 1525-1530. Link to abstract
Ellers, O., 1997. Book Review of Echinoderm Studies 5,. M. Jangoux and J.M. Lawrence, eds., A.A. Balkema, publ. The Quarterly Review of Biology 72(3): 340.
Ellers, O. & M. Telford. 1996. Advancement mechanics of growing teeth in sand dollars (Echinodermata, Echinoidea): a role for mutable collagenous tissue. Proc. R. Soc. Lond. B 263: 39-44. Link to abstract
Irschick, D. J., C. C. Austin, K. Petren, R. N. Fisher, J. B. Losos and O. Ellers. 1996. A comparative analysis of clinging ability among pad-bearing lizards. Biological Journal of the Linnean Society 59: 21-35. Link to abstract
Ellers, O. 1995. Behavioral control of swash-riding in the clam Donax variabilis. Biol. Bull. 189: 120-127. Link to pdf
Ellers, O. 1995. Discrimination among wave-generated sounds by a swash-riding clam. Biol. Bull. 189: 128-137. Link to pdf
Ellers, O. 1995. Form and motion of Donax variabilis in flow. Biol. Bull. 189: 138-147. Link to pdf
Lelievre, B., Telford, M. , Ellers, O. 1995. The role of collagen in reacting axial forces in the teeth of sand dollars (Echinoidea: Clypeasteroida). Fourth European Echinoderms Conference, London
Ellers, O. 1993. A mechanical model of growth in regular sea urchins: predictions of shape and a developmental morphospace. Proc. R. Soc. Lond. B 254: 123-129. Link to abstract
Moore, A.M.F. , O. Ellers 1993. A functional morphospace, based on dimensionless numbers, for a circumferential calcite stabilizing structure in sand dollars. J. Theor. Biol. 162: 253-266. Link to abstract
Ellers, O., Telford, M. 1992. Causes and consequences of fluctuating coelomic pressure in sea urchins. Biol. Bull., 182: 424-434. Link to pdf
Ellers, O., Telford, M. 1991. Forces generated by the jaws of clypeasteroids (Echinodermata: Echinoidea). J. exp. Biol., 155: 585-603. Link to pdf
Ellers, O. 1987. Passive orientation of benthic animals in flow. In W. F. Herrnkind & A. B. Thistle (Eds.), Signposts in the Sea, Proceedings of a multidisciplinary workshop on marine animal orientation and migration, (pp. 45-68). Tallahassee: Dept. of Biological Science, Florida State University.
Telford, M., Mooi, R. , Ellers, O. 1985. A new model of podial deposit feeding in the sand dollar, Mellita quinquiesperforata (Leske): The sieve hypothesis challenged. Biol. Bull., 169: 431-448. Link to pdf
Ellers, O., Telford, M. 1984. Collection of food by oral surface podia in the sand dollar, Echinarachnius parma (Lamarck). Biol. Bull., 166: 574-582. Link to pdf
Askins, M*, Lonati, G,* Guttenplan, K,* Fahey, A,* Johnson, A, Ellers, O. (2012) Externally visible polyfluorochrome marking of urchins: growth comparisons between lab-reared and tidepool urchins. Integrative and Comparative Biology, Poster Presentation, Annual Meeting Abstract, Jan. 3-7, 2012 Charleston, NC
Ellers, O., Yoshimura, K., Motokawa, T., Johnson, A.S. (2010) Why not walk faster, underwater?. Integrative and Comparative Biology, Annual Meeting Abstract, Jan. 3-7, 2010 Seattle, WA
Johnson, A.S., Ellers O. (2010). Precise measurement of growth using multiple fluorochrome markers, the cubed root of weight and a new growth function. Integrative and Comparative Biology, Annual Meeting Abstract, Jan. 3-7, 2010 Seattle, WA
Brasili, A.*; Johnson, A.S.; Ellers, O. (2010) Temperature and size-dependent growth in a marine ectotherm: the green sea urchin Strongylocentrotus droebachiensis. Integrative and Comparative Biology, Annual Meeting Abstract, Jan. 3-7, 2010 Seattle, WA
Norton*, E; Ellers, O; Johnson, A.S. (2010) Testing an inverted pendulum model for underwater walking in the crab Carcinus maenus. Integrative and Comparative Biology, Annual Meeting Abstract, Jan. 3-7, 2010 Seattle, WA
Ellers, O., Yoshimura, K., Motokawa, T., Johnson, A.S. 2009. An inverted pendulum model for underwater walking. Integrative and Comparative Biology, Annual Meeting Abstract 74.1, Jan. 3-7, 2009, Boston, MA
Johnson, A., Selden, R., Ellers, O. 2009. Crab scent induces thicker skeletons, smaller gonads and size-specific adjustments in growth rate in sea urchins. Integrative and Comparative Biology, Annual Meeting Abstract 74.1, Jan. 3-7, 2009, Boston, MA
Johnson, A.S., Ellers, O., Butler, M. 2006. Barbs of a feather bend (and twist) together. Integr. Comp. Biol. 46(1): e70; doi:10.1093/icb/icl056
Johnson, A.S., Ellers, O. 2006. A new fluorochrome-based identification tag for sea urchins for use in a hatchery and lease-site aquaculture. Northeast Aquaculture Conference and Exposition. Mystic, Connecticut. December, 2006.
Ellers, O., Johnson, A.S. 2006. Temperature determines size and time-to-size in urchins: calibration of size-temperature effects in marine ectotherms. International Echinoderm Conference, University of New Hampshire, August 2006.
Johnson, A.S., Ellers, O., Wright, M., Selden, R, Stranges, B. 2006. Is there an oxygen-limited lag phase in early growth in sea urchins, Strongylocentrotus droebachiensis? International Echinoderm Conference, University of New Hampshire, August 2006.
Johnson, A.S., Ellers, O., Wright, M., Stranges, B. 2005. Implications of transport processes and 2/3 power metabolic scaling to Bertalanffy and bimodal growth in sea urchins. Integr. Comp. Biol. 44(6):709.
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