10.5061/DRYAD.FQ7H2
Foote, Michael
University of Chicago
Cooper, Roger A.
University of California, Riverside
Crampton, James S.
GNS Science
Sadler, Peter M.
University of California, Riverside
Data from: Diversity-dependent evolutionary rates in early Paleozoic
zooplankton
Dryad
dataset
2018
diversity dynamics
Diversity-dependence
plankton evolution
Graptoloidea
2018-02-09T17:27:38Z
2018-02-09T17:27:38Z
en
https://doi.org/10.1098/rspb.2018.0122
89039 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
The extent to which biological diversity affects rates of diversification
is central to understanding macroevolutionary dynamics, yet no consensus
has emerged on the importance of diversity-dependence of evolutionary
rates. Here we analyse the species-level fossil record of early Paleozoic
graptoloids, documented with high temporal resolution, to test directly
whether rates of diversification were influenced by levels of standing
diversity within this major clade of marine zooplankton. To circumvent the
statistical regression-to-the-mean artefact, whereby higher- and
lower-than-average values of diversity tend to be followed by negative and
positive diversification rates, we construct a non-parametric, empirically
scaled, diversity-independent null model by randomizing the observed
diversification rates with respect to time. Comparing observed
correlations between diversity and diversification rate to those expected
from this diversity-independent model, we find evidence for negative
diversity-dependence, accounting for up to 12% of the variance in
diversification rate, with maximal correlation at a temporal lag of ~1
million years. Diversity-dependence persists throughout the Ordovician and
Silurian, despite a major increase in the strength and frequency of
extinction and speciation pulses in the Silurian. In contrast to some
previous work, we find that diversity-dependence affects rates of
speciation and extinction nearly equally on average, although subtle
differences emerge when we compare the Ordovician and Silurian.
Supplementary Table 1Diversity and evolutionary rates in
Ordovician-Silurian graptoloidsSupplementaryTable1.xlsxSupplementary R
CodeR code used for simulations and analysesSupplementaryCode.v2.R