A simplified correlation between vertebrate evolution and Paleozoic geomagnetism
- Published
- Accepted
- Subject Areas
- Evolutionary Studies, Paleontology
- Keywords
- Paleozoic, geomagnetism, vertebrates, evolution, paleontology, compendium
- Copyright
- © 2019 Staub
- Licence
- This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ Preprints) and either DOI or URL of the article must be cited.
- Cite this article
- 2019. A simplified correlation between vertebrate evolution and Paleozoic geomagnetism. PeerJ Preprints 7:e28002v2 https://doi.org/10.7287/peerj.preprints.28002v2
Abstract
Background. Despite a fifty-year failure of paleontologists to find a viable connection between geomagnetic polarity reversals and evolutionary patterns, recent paleobiology databases show that the early appearance, radiation, and diversification of Paleozoic vertebrates tends to occur during periods having frequent collapses of the Earth’s geomagnetic field. The transition time during the collapse of the Earth’s protective magnetic shield can last thousands of years, and the effects on biota are unknown. Solar and cosmic radiation, volcanism, climate alteration, low-frequency electromagnetic fields, depletion of ozone, the stripping of atmospheric oxygen, and increasing production of Carbon14 in the stratosphere have been proposed as possible causes, but previous studies have found no effects.
Methods. Using published databases, we compiled a spreadsheet showing the first appearance of 2210 age-dated genera with each genus assigned to one of eleven major taxonomic groups. From Gradstein’s Geologic Time Scale 2012, we delineated 17 Paleozoic zones with either high or low levels of polarity reversals.
Results. From our compilation, 737 Paleozoic vertebrates represent the initial radiation and diversification of individual Paleozoic vertebrate clades. After compensating for sample-size and external geologic and sampling biases, the resulting Pearson’s correlation coefficient between the 737 genera and geomagnetic polarity zones equals 0.89. These results suggest a strong relationship exists between Paleozoic vertebrates and geomagnetism.
Discussion. The question: is this apparent connection between geomagnetism and the evolution of Paleozoic vertebrate due to environmental or biologic factors. If biologic, why are vertebrates the only biota effected? And after an indeterminate period of time, how do vertebrates become immune to the ongoing effects of polarity reversals?
Author Comment
In this new version, we have added Table 3 (A condensed spreadsheet showing our 2210 Paleozoic vertebrate genera). Each genus shows its clade, geologic stage of first appearance, age range in million years, and is placed in its specific polarity zone (proportionately, if needed).
Supplemental Information
Table 3: Condensed dataset showing 2210 Paleozoic vertebrate genera
Table 3: Condensed dataset showing 2210 Paleozoic vertebrate genera. Column A is the numerical representation of each clade: 1=early jawless fish; 2=armored fish; 3=cartilage fish; 4=bony and ray-finned fish; 5=lung & lobe-finned fish; 6=early tetrapods; 7=amphibians; 8=early reptiles (amniota); 9=reptiles; 10=pelycosaurs; 11=therapsids (early “mammals”). Column B numerically shows the early-phase genera of each clade. Column C shows the clade. Column D is the genus. Column E shows the geologic stage where first discovered. Columns F & G show the age in ma (million years ago). Column H to Z show the proportional value of each genus in the 17 polarity zones. A complete color-coded Excel dataset, showing the phylogeny of each genus, should be available at Dryad (doi:10.5061/dryad.1ns1m8q0).