Evolutionary biologists have long sought to explain the distribution of traits across the tree of life and, in particular, why some traits are common while others remain rare. The number of taxa with a given trait is shaped largely by the transition rates toward and away from that state as well as the diversification rates for taxa with the trait. This project will test the role of these macroevolutionary forces in shaping the distribution of red flowers in the potato family, Solanaceae. Although red-flowered taxa are spread across 13 genera, they are extremely rare, accounting for only 1% of the roughly 2850 species in the family. Using phylogenetic, anatomical, and biochemical methods, this project will (1) identify the origins and mechanistic basis for red coloration in Solanaceae, (2) test the hypothesis that red flowers remain rare due to reduced rates of diversification, and (3) examine whether this effect is contingent on the developmental pathway involved.
Supported by NSF-DEB 1413855
Relevant publications:
Ng, J.+ & S. D. Smith. 2018. Why are red flowers so rare? Testing the macroevolutionary causes of tippiness. Journal of Evolutionary Biology 31: 1863-1875. Link, Reprint Request
Ng, J., and S. D. Smith. 2016. How to make a red flower: the combinatorial effects of pigments. AOB Plants 8: plw013. Link
Ng, J., and S. D. Smith. 2016. Widespread flower color convergence in Solanaceae via alternate biochemical pathways. New Phytologist 209: 407-417. PDF
Ng, J., and S. D. Smith. 2014. How traits shape trees: New approaches for detecting character state-dependent lineage diversification. Journal of Evolutionary Biology 27: 2035-2045. PDF
Muchhala, N., S. Johnsen, and S. D. Smith. 2014. Competition for hummingbird pollination shapes flower color variation in Andean Solanaceae. Evolution 68: 2275-2286. PDF