TY - JOUR
T1 - Non-equilibrium dynamics and floral trait interactions shape extant angiosperm diversity
AU - O'Meara, Brian C.
AU - Smith, Stacey D.
AU - Armbruster, W. Scott
AU - Harder, Lawrence D.
AU - Hardy, Christopher R.
AU - Hileman, Lena C.
AU - Hufford, Larry
AU - Litt, Amy
AU - Magallón, Susana
AU - Smith, Stephen A.
AU - Stevens, Peter F.
AU - Fenster, Charles B.
AU - Diggle, Pamela K.
N1 - The working group that led to this publication was supported by the National Evolutionary Synthesis Center (NESCent), NSF no. EF-0423641
PY - 2016/5/11
Y1 - 2016/5/11
N2 - Why are some traits and trait combinations exceptionally common across the tree of life, whereas others are vanishingly rare? The distribution of trait diversity across a clade at any time depends on the ancestral state of the clade, the rate at which new phenotypes evolve, the differences in speciation and extinction rates across lineages, and whether an equilibrium has been reached. Here we examine the role of transition rates, differential diversification (speciation minus extinction) and non-equilibrium dynamics on the evolutionary history of angiosperms, a clade well known for the abundance of some trait combinations and the rarity of others. Our analysis reveals that three character states (corolla present, bilateral symmetry, reduced stamen number) act synergistically as a key innovation, doubling diversification rates for lineages in which this combination occurs. However, this combination is currently less common than predicted at equilibrium because the individual characters evolve infrequently. Simulations suggest that angiosperms will remain far from the equilibrium frequencies of character states well into the future. Such non-equilibrium dynamics may be common when major innovations evolve rarely, allowing lineages with ancestral forms to persist, and even outnumber those with diversification-enhancing states, for tens of millions of years.
AB - Why are some traits and trait combinations exceptionally common across the tree of life, whereas others are vanishingly rare? The distribution of trait diversity across a clade at any time depends on the ancestral state of the clade, the rate at which new phenotypes evolve, the differences in speciation and extinction rates across lineages, and whether an equilibrium has been reached. Here we examine the role of transition rates, differential diversification (speciation minus extinction) and non-equilibrium dynamics on the evolutionary history of angiosperms, a clade well known for the abundance of some trait combinations and the rarity of others. Our analysis reveals that three character states (corolla present, bilateral symmetry, reduced stamen number) act synergistically as a key innovation, doubling diversification rates for lineages in which this combination occurs. However, this combination is currently less common than predicted at equilibrium because the individual characters evolve infrequently. Simulations suggest that angiosperms will remain far from the equilibrium frequencies of character states well into the future. Such non-equilibrium dynamics may be common when major innovations evolve rarely, allowing lineages with ancestral forms to persist, and even outnumber those with diversification-enhancing states, for tens of millions of years.
U2 - 10.1098/rspb.2015.2304
DO - 10.1098/rspb.2015.2304
M3 - Article
SN - 0962-8452
VL - 283
JO - Proceedings of the Royal Society B: Biological Sciences
JF - Proceedings of the Royal Society B: Biological Sciences
IS - 1830
M1 - 20152304
ER -