Project: Repeated Evolution of small body size in Island Reptiles

Genetics, Physiology and Life History

The "Island Rule" is a worldwide phenomenon of rapid body size evolution on islands where smaller taxa show a tendency towards dwarfism, and larger taxa show a tendency towards gigantism. On the Channel Islands off the coast of California three species of reptiles have evolved to be dwarf relative to the mainland populations. We are using the repeated evolution of dwarfism to understand  how molecular networks (genes, hormone regulation, etc) underlying complex traits, such as body size, can evolve. These molecular data are integrated with estimates of reproductive output obtained through advanced field-portable ultrasound technology which can inform us about the life history evolution of these species as well that allows us to extend our understanding of the process of convergent evolution on correlated life-history traits.


Principal Investigators:

  • Tonia Schwartz, Auburn University

  • Amanda Sparkman, Westmont College

Graduate Students:

  • Amanda Clark, Auburn University

Undergraduate Students:​

  • Milica Courtenay

We are grateful for funding from the following sources that have supported this research.
  • National Science Foundation, Graduate Research Fellowship to Ms. Amanda Clark

Related Media Links

National Parks Service, 2017: Channel Islands Serve As Reptile Evolution Laboratory

Related Publications

Sparkman, AM, AD ClarkG, LJ BrummettU, KR ChismU, LL CombrinkU, NM KabeyU, TS Schwartz. 2018. Convergence in reduced body size, head size, and blood glucose in three island reptiles. Ecology and Evolution. 8(12):6169-6182. doi: 10.1002/ece3.4171

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