T149 Phylogenetic and Computational Approaches in Paleobiology and Paleoecology I

Tuesday, 17 October 2023
8:00 AM - 12:00 PM
301 / 302

EVOLVABILITY PREDICTS EVOLUTIONARY DIVERGENCE ACROSS MICRO- AND MACROEVOLUTION

Paper number: T149-5
Program: Technical Sessions
Time: 8:50 AM – 9:05 AM

Authors

Abstract

Heritable variation is a prerequisite for evolutionary change. Yet, whether within-population variation (evolvability) is relevant on macroevolutionary timescales is debated. We compiled two extensive datasets on fossil and contemporary taxa to investigate whether evolvability predicted phenotypic evolution across different timescales.

For the contemporary taxa, we combined within-population additive genetic variance with data on among-population and among-species variation (1051 evolvability estimates and 2694 population means from a total of 409 traits in 123 species). For the fossil taxa, we combined within-sample variance with changes in trait mean across 589 fossil time-series from 150 independent lineages for a total of 10,594 samples.

The two datasets offer complementary strengths. The contemporary data provide measures of evolvability based on additive genetic variance, but the exact history of population divergence is usually unknown, so that populations must be considered as tips on polytomies. The fossil time-series data allow investigating the dynamic relationship between divergence and evolvability through time but lack direct information about genetic variation. Nevertheless, we show in the contemporary data that across traits there is a strong (R2 = 83%) and isometric scaling relationship between measures of additive and phenotypic variance, which can be used to translate phenotypic variation in fossil samples into estimates of evolvability.

Our results show that macroevolutionary changes are not independent of microevolutionary potential for evolution as both the contemporary and fossil data set firmly establish the existence of a positive scaling relationship between evolutionary divergence and evolvability. We suggest an effect of evolvability on phenotypic divergence can be explained by the influence of genetic constraints on lineage’s ability to track rapid stationary environmental fluctuations.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-392160

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