Abstract Detail

Macroevolution

Diggle, Pamela Kathleen [1], O'Meara, Brian C. [2], Smith, Stacey D. [3], Armbruster, Scott [4], Harder, Lawrence D [5], Hardy, Christopher [6], Hileman, Lena C [7], Hufford, Larry [8], Litt, Amy [9], Smith, Stephen [10], Stevens, Peter [11], Magallón, Susana [12], Fenster, Charlie [13].

Non-equilibrium dynamics and floral trait interactions shape extant angiosperm diversity.

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.

1 - University Of Connecticut, Department Of Ecology And Evolutionary Biology, 75 North Eagleville Road, Storrs, CT, 06269, USA
2 - University of Tennessee, Knoxville, Department of Ecology and Evolutionary Biology,, Knoxville, TN
3 - University Of Colorado-Boulder, School Of Biological Sciences, Campus Box 334, Boulder, CO, 80309-0334, USA
4 - University of Portsmouth, Portsmouth, School of Biological Sciences, UK
5 - University Of Calgary, Department Of Biological Sciences, 2500 University Drive NW, Calgary, AB, T2N 1N4, Canada
6 - James C. Parks Herbarium, 288 Roddy Science Building, 50 E Frederick St, Millersville, PA, 17551, USA
7 - University Of Kansas, 1200 Sunnyside Avenue, Lawrence, KS, 66045, USA
8 - Washington State University, SCHOOL OF BIOLOGICAL SCIENCES, 312 Abelson Hall, PULLMAN, WA, 99164-4236, USA
9 - University of California, Riverside, 900 University Avenue, Riverside, CA, 92521, United States
10 - University of Michigan, Ecology and Evolutionary Biology, 2071A Kraus Natural Science Building, Ann Arbor, MI, 48109, United States
11 - Missouri Botanical Garden, St. Louis, MO
12 - Instituto De Biologia, Universidad Nacional Autonoma De Mexico, 3er Circuito De Ciudad Universitaria, Del. Coyoacan, A.P. 70-233, Mexico City, Mexico D.F., N/A, 04510, Mexico
13 - South Dakota State University, Department of Biology and Microbiology, Brookings, SD

Keywords:
diversification
floral evolution
macroevolution
non-equilibrium
floral symmetry
pollination
speciation.

Presentation Type: Oral Paper
Session: 10, Macroevolution
Location: 202/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:00 PM
Number: 10014
Abstract ID:954
Candidate for Awards:None