BA - Augustana College
MS - Northwestern University
PhD- Northwestern University
Temperature Effects on Early Development
Adaptations of all organisms are tested through continuing interactions with numerous environmental factors including temperature. These interactions begin early in development. I have investigated temperature tolerances of embryos and larvae of several animals including the crown-of-thorns starfish in Australia and several American and Australian sea urchins and sand dollars. My students also have studied temperature adaptations of developing Medaka fish.
References:
Johnson, L.G., J.E. Chenoweth, and B.L. Bingham. 1990.
Population differences and thermal acclimation in temperature responses of developing sea urchin embryos. Proc. S. D. Acad. Sci. 69:99-108.Johnson, L.G. and R.C. Babcock. 1994.
Temperature and the larval ecology of the crown-of-thorns starfish, Acanthaster planci. Biol. Bull. 187:304-308.Rahn, A. B., M. A. Cade, and L. G. Johnson. 1996. Parental acclimation and developmental temperature relationships of the Japanese Medaka, Oryzias latipus. Proc. S. D. Acad. Sci. 75:203-204.
Bingham, B.L., M. Bacigalupi, and L.G. Johnson. 1997. Temperature adaptations of embryos from intertidal and subtidal sand dollars. Northwest Science 71:108-114.
Thyroid Hormones and Animal Development
Some years ago, my students and I investigated effects of thyroid hormones on differentiation of skin derivatives in vertebrate animals, but recently my research has been focused on thyroxine effects on development of invertebrate animals including the crown-of-thorns starfish in Australia and sea urchins in New Zealand.
References:
Lawrenz, N.K. and L.G. Johnson. 1970.
Thyroid hormone effects on chick scale morphogenesis and keratinization. J. Embryol. Exp. Morphol. 24:65-71.Johnson, L.G. And C.M. Cartwright. 1996. Thyroxine-accelerated larval development in the crown-of-thorns starfish, Acanthaster planci. Biol. Bull. 190:299-301.
Johnson, L.G. 1997 Thyroxine's evolutionary roots. Persp. Biol. Med. 40:529-535.
Johnson, L.G., J.E. Kullbom, S.L. Priesz, S.N. Strand, and K.M. Faber. 1997.
Thyroxine effects on invertebrate development. Proc.S. D. Acad. Sci. 76:291-292.Johnson, L. G. 1998. Stage-dependent thyroxine effects on sea urchin development. N. Z. J. Mar. Freshwater Res. 32:531-536.
Like all Augustana faculty members, I am first of all a teacher and thus I spend the greater part of my time and energy on teaching courses, advising students, and guiding independent study projects. Further, I have contributed to teaching beyond Augustana as the author of a laboratory manual (70+ kb) for upper division Developmental Biology courses and the leader of a summer workshop on Developmental Biology teaching at the University of Maine's Darling Marine Center. The workshop has been held eleven times since 1992 and more than eighty university and college faculty members from across the U.S. and Canada have participated in it.
References:
Johnson, L.G. 2001. Patterns and Experiments in Developmental Biology. Wm. C. Brown Publishers
For information on my "Developmental Biology Teaching Workshop," contact:
Tim Miller, Darling Marine Center
193 Clark's Cove Road
Walpole, ME 04573
e-mail: temiller@maine.maine.edu
Comments? Questions? Please contact steven.matzner@augie.edu
Last modified