Common Ancestry Is a Poor Predictor of Competitive Traits in Freshwater Green Algae.
Phytoplankton species traits have been used to successfully predict the outcome of competition, but these traits are notoriously laborious to measure. If these traits display a phylogenetic signal, phylogenetic distance (PD) can be used as a proxy for trait variation. We provide the first investigation of the degree of phylogenetic signal in traits related to competition in freshwater green phytoplankton. We measured 17 traits related to competition and tested whether they displayed a phylogenetic signal across a molecular phylogeny of 59 species of green algae. We also assessed the fit of five models of trait evolution to trait variation across the phylogeny. There was no significant phylogenetic signal for 13 out of 17 ecological traits. For 7 traits, a non-phylogenetic model provided the best fit. For another 7 traits, a phylogenetic model was selected, but parameter values indicated that trait variation evolved recently, diminishing the importance of common ancestry. This study suggests that traits related to competition in freshwater green algae are not generally well-predicted by patterns of common ancestry. We discuss the mechanisms by which the link between phylogenetic distance and phenotypic differentiation may be broken.
BU-G11 Überlandstrasse 133, Department of Aquatic Ecology, Eawag (Swiss Federal Institute of Aquatic Science and Technology), 8600, Dübendorf, Switzerland; 1556 Dana Building, 440 Church Street, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI, 48109-1041, United States of America.
Anita
A
Narwani
4101 Life Sciences Building, UCEN Road, Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, 93106, United States of America.
Markos A
MA
Alexandrou
1556 Dana Building, 440 Church Street, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI, 48109-1041, United States of America.
James
J
Herrin
1556 Dana Building, 440 Church Street, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI, 48109-1041, United States of America.
Alaina
A
Vouaux
1556 Dana Building, 440 Church Street, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI, 48109-1041, United States of America.
Charles
C
Zhou
4101 Life Sciences Building, UCEN Road, Department of Ecology, Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, 93106, United States of America.
Todd H
TH
Oakley
1556 Dana Building, 440 Church Street, School of Natural Resources and Environment, University of Michigan, Ann Arbor, MI, 48109-1041, United States of America.
Bradley J
BJ
Cardinale
D000460:Chlorophyta / Q000235:genetics* / Q000378:metabolism; D019143:Evolution, Molecular; D005618:Fresh Water; D008962:Models, Theoretical; D009566:Nitrates / Q000378:metabolism; D010641:Phenotype; D010710:Phosphates / Q000378:metabolism; D010802:Phylogeny; D010839:Phytoplankton / Q000235:genetics* / Q000378:metabolism; D013045:Species Specificity
D009566:Nitrates; D010710:Phosphates