Senior Project Advisor

Peterson, Merrill A., 1965-

Document Type


Publication Date

Spring 2020


hyperoxia, hypoxia, entomology, paleontology, experimental paleoentomology


Insects provide powerful examples of the responses of organisms to environmental change. For example, insect body size gives us insight into the consequences of climate change due to shifts in atmospheric composition, both in the present and in the past. Indeed, one common hypothesis behind the enormous sizes of insects during the late Carboniferous to early Permian (323.2 to 265.0 million years ago) is that such sizes were enabled by elevated oxygen levels (hyperoxia) during the Permo-Carboniferous, when atmospheric oxygen was as high as 60% greater than its present-day concentration. To examine whether the giant body sizes of insects were solely a response to a high partial pressure of oxygen, I assess the strengths and weaknesses of studies to date and address the need for further research that would allow for more robust tests of this hypothesis. Conclusions from the growing body of literature on geomagnetic polarity reversal, insect physiology, paleoecology, paleoclimatology, and paleoentomology suggest that even present-day oxygen levels might have been enough to induce gigantism, but can no longer, due to more recent selection against large insects that has limited their maximum body sizes since the Permo-Carboniferous. Additionally, more definitive studies on long-term evolutionary changes of insect size in high oxygen levels are needed before the question of whether high oxygen levels drive insect gigantism can be adequately answered.



Subjects - Topical (LCSH)

Paleoentomology; Paleontology--Carboniferous; Insect--Size; Oxygen--Physiological effect


student projects; term papers




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