Professor of Biology
Phone (951) 827-5820
Ph.D., University of Pennsylvania, 1980
My general interest is in studying the process of evolution by natural selection from an experimental perspective and testing evolutionary theory in natural populations. I primarily work on guppies from the Caribbean Island of Trinidad. Guppies are found in high and low predation environments that differ in the species of predators that guppies co-occur with. This contrast is found repeatedly in different drainages and the different predation regimes are often right next to one another, separated by a waterfall. Guppies from high predation environments experience much higher mortality rates. High mortality is associated with earlier maturity, a higher rate of investment of resources in reproduction, and the production of more and smaller offspring. All of these differences have a genetic basis. Mortality rates can be manipulated by either introducing guppies from high predation localities into sites from which they and their predators had previously been excluded by waterfalls, thus lowering mortality rates, or by introducing predators into low predation sites over barrier waterfalls, thus increasing mortality rates. Such experiments have shown that live histories evolve as predicted by theory and in a fashion that is consistent with the earlier comparative studies They have also shown that evolution by natural selection can be remarkably fast, on the order of four to seven orders of magnitude faster than inferred from the fossil record. I am currently studying the evolution of aging in this same system.
Dr. Reznick participates in IDEA, the UCR Institute for the Development of Educational Applications and serves as the UCR co-Associate Director of NERE, the Network
for Experimental Research on Evolution.
Some Representative Publications
- Reznick, D. N., Bryant, M., Roff, D. A., Ghalambor, G. and Ghalambor,
D. E. Effects of extrinsic mortality on the evolution of senescence in guppies
(Poecilia reticulata). Nature. (in press)
- Reznick, D. N. and C. Ghalambor. Can commercial fishing cause evolution?
Answers from guppies. Canadian Journal of Fisheries and Aquatic Sciences. (in
- Ghalambor, C. K., D. N. Reznick and J. A. Walker. Constraints on adaptive
The functional tradeoff between reproduction and fast-start swimming performance
Trinidadian guppy (Poecilia reticulata). American Naturalist 164,
- Ghalambor, C. K., J. A. Walker, and D. N. Reznick. Multi-trait selection,
constraints on the evolution of burst swimming performance. Integrative and
Comparative Biology 43, 431-438 (2003).
- Reznick, D. N., M. Mateos, and M. S. Springer. Independent origins
and rapid evolution
of the placenta in the fish genus Poeciliopsis. Science 298,
- Reznick, D. N., M. J. Bryant, and F. Bashey. r- and K-selection revisited:
The role of density, resources, and environmental fluctuations in life-history
evolution. Ecology 83, 1509-1520 (2002).
- Reznick, D. N. and C. Ghalambor. The population ecology of contemporary
What empirical studies reveal about the conditions that promote adaptive
evolution. Genetica 112/113, 183-198 (2002).
- Morey, S and D. Reznick. A comparative analysis of plasticity in larval
development in three species of spadefoot toads. Ecology 81, 1736-1749 (2000).
- Reznick, D. N., L. Nunney and A. Tessier. Big houses, big cars, superfleas
and the costs of reproduction. Trends in Ecology and Evolution 15, 421-425
- Reznick, D. N., Shaw, F. H., Rodd, F. H. & Shaw, R. G. Evaluation
of the rate of evolution in natural populations of guppies (Poecilia
reticulata). Science 275,
- Reznick, D. N. Life history evolution in guppies (Poecilia reticulata): Guppies as a model for studying the evolutionary biology of aging. Experimental Gerontology 32, 245-258 (1997).
- Reznick, D. N., Butler M. J., I., Rodd, F. H. & Ross, P. Life
history evolution in guppies (Poecilia reticulata). 6. Differential mortality as a mechanism for natural selection. Evolution 50, 1651-1660 (1996).
- Reznick, D. N., Rodd, F. H. & Cardenas, M. Life-history
evolution in guppies (Poecilia reticulata: Poeciliidae). IV. Parallelism in life-history phenotypes. American Naturalist 147, 319-338. (1996).
- Reznick, D. N. & Bryga, H. Life-history evolution
in guppies (Poecilia reticulata: Poeciliidae). V. Genetic basis of parallelism in life histories. American Naturalist 147, 339-359 (1996).
- Reznick, D. A., Bryga, H. & Endler, J. A. Experimentally induced life-history evolution in a natural population. Nature 346, 357-359 (1990).
- Reznick, D. N. Life history evolution in guppies. 2. Repeatability of field observations and the effects of season on life histories. Evolution 43, 1285-1297 (1989).
- Reznick, D. N. & Bryga, H. Life-history evolution in guppies. 1. Phenotypic and genotypic changes in an introduction experiment. Evolution 41, 1370-1385 (1987).
- Reznick, D. N. & Endler, J. A. The
impact of predation on life history evolution in Trindadian guppies (Poecilia
reticulata). Evolution 36, 160-177 (1982).
- Biology 105, Evolution
- Biology 161A, Functional Morphology of the Vertebrates
- Biology 216, The Theory of Evolution