Recent geological models indicate a marked increase in the partial pressure of oxygen (pO2) during the Permo-Carboniferous with an upper value of ~31% and a sharp decline at the Permo-Triassic boundary to as low as ~13%. These variations in atmospheric oxygen have been invoked to explain a vast array of evolutionary events, including major extinctions, changes in community structure and diversity, and the conquest of land by animals. One of the most oft-cited and dramatic proposed effects of this oxygen variation is that elevations in pO2 (hyperoxia) allowed increases in body size of vertebrates and insects. However, the intriguing hypothesis that hyperoxia was responsible for insect gigantism is weakened by two major problems: 1) the lack of statistical evidence that body size correlates with oxygen levels in the primitive taxa that were present 200-300 mya when the major changes in pO2 occurred and 2) a lack of modern physiological studies to support this hypothesis. Research in this project will address both of these issues. Specific student projects will include study of the effect of oxygen level on dragon fly growth, study of the effect of oxygen level on cockroach tracheal diameters, and examination of the effect of taxonomic group and oxygen through time on fossil insect wing lengths.
|Effective start/end date||4/1/08 → 3/31/12|
- National Science Foundation (NSF): $536,000.00