Kathleen Kovalevski Smith

Professor Emerita of Biology

130 Science Drive, Room 122 Duke Box 90338, Durham, NC 27708
Campus Box: 
Box 90338, Durham, NC 27708-0338
(919) 684-3402
My current work is a focus on the relation between evolution and development in the mammalian skull. My model system involves comparisons of development in placental and marsupial mammals. These mammals are characterized by different developmental trajectories, extending back to some of the earliest events of differentiation, largely as a result of their different life history adaptations. My work focuses on a number of different questions. First, what are the differences in the development of the craniofacial region in marsupial and placental mammals? The head is particularly important in the comparison between marupials and placentals, as many cranial systems must be functional at birth in marsupials, despite the fact that morphogenesis has just started. Second, how do the differences in the developmental pattern reflect the necessities of the marsupial reproductive strategy? What is the adaptive significance of the developmental differences and what constraints might be operating? Here I am looking at development not as merely a means to produce an adult, but as a feature that has an evolutionary significance of its own. Third, what can this comparative approach tell us about mammalian head development in general? There are many differences in the way the head develops in marsupials and placentals. It is reasonable to assume that those elements that develop independently (e.g., appear in different temporal or spatial sequences in the two taxa) are elements that are not mechanistically linked or integrated, whereas those that are consistently associated in the two taxa, despite changes in other structures, may be linked by developmental mechanisms. I am using this comparative approach to examine developmental integration and plasticity. Fourth, what are the developmental mechanisms underlying these evolutionary changes? The most significant differences in development in the two taxa reflect differences in the relative timing of the development of the central nervous system and somatic structures. Hypotheses on many levels have been proposed on the possible mechanistic relations between the development of the CNS and the cranial skeleton. To what extent can these hypotheses on mechanistic relation be tested by comparing events in organisms in which the elements are shifted dramatically in time or space? The comparison is, in essence, a natural experiment. Finally, have the specific developmental patterns of marsupial and placental mammals had an impact on the evolutionary diversity and success of these organisms?

My current project focuses on the earliest patterning events. These projects include a study of heterochronies in the earliest morphological and genetic events in the head of marsupial and placental mammals, a study of neural crest in marupial mammals, and a study of patterns of Hox gene expression along the developing body axis, relations between the brain and cranial skeleton.


  • Ph.D., Harvard University 1980

  • B.A., University of California - Santa Cruz 1973

KIER, W. M., and K. K. SMITH. “Tongues, tentacles and trunks: the biomechanics of movement in muscular‐hydrostats.” Zoological Journal of the Linnean Society 83, no. 4 (January 1, 1985): 307–24. https://doi.org/10.1111/j.1096-3642.1985.tb01178.x. Full Text

Smith, K. K., and W. L. Hylander. “Strain gauge measurement of mesokinetic movement in the lizard Varanus exanthematicus.The Journal of Experimental Biology 114 (January 1985): 53–70.

SMITH, K. K. “THE MORPHOLOGY AND FUNCTION OF THE TONGUE IN LIZARDS.” American Zoologist 23, no. 4 (January 1, 1983): 1028–1028.

KIER, W. M., and K. K. SMITH. “TONGUES, TENTACLES AND TRUNKS - THE BIOMECHANICS OF MOVEMENT IN MUSCULAR-HYDROSTATS.” American Zoologist 23, no. 4 (January 1, 1983): 904–904.

Kier, W. M., and K. K. Smith. “The biomechanics of movement in tongues and tentacles.” Journal of Biomechanics 16, no. 4 (January 1983): 292–93. https://doi.org/10.1016/0021-9290(83)90176-8. Full Text


Smith, K. K. “Mechanical significance of streptostyly in lizards [20].” Nature 283, no. 5749 (December 1, 1980): 778–79. https://doi.org/10.1038/283778a0. Full Text