Spatiotemporal patterns of marine biodiversity through the Phanerozoic

Thesis

The fossil record offers direct evidence of how life navigates major environmental upheavals, providing a critical framework for anticipating extinction risk in the face of accelerating anthropogenic climate change. Drawing on global marine invertebrate data across the Phanerozoic, this thesis shows that extinction risk is governed by the complex interplay of biological traits, paleogeographic constraints, and especially the magnitude of climate change. Traits such as broad geographic range and physiological tolerance mediate risk during stable intervals, yet even the most resilient taxa can be overwhelmed when climate shifts are sufficiently extreme. Quantitative analyses reveal that paleogeographic boundary conditions, most notably coastline geometry, nonrandomly shape extinction during mass extinctions and hyperthermals, challenging classic paradigms of extinction as purely stochastic. Finally, the inconsistent coupling of realized niches to environmental change over time highlights the complex idiosyncratic response of surviving taxa to climate change. Together, these findings highlight the power of paleontological frameworks to identify which species and settings were most vulnerable to climate change in the past and will be prone to extinction as climate change intensifies.

Authors: Malanoski, C

• DOI: 10.5287/ora-qmoq2g8v1
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: climate change; mass extinction; extinction selectivity
• Subjects: Paleobiology