Chapelle & Peck 1999: "Oxygen supply may also have led to insect gigantism in the Carboniferous period, because atmospheric oxygen was 30-35% (ref. 7). The demise of these insects when oxygen content fell indicates that large species may be susceptible to such change. Giant amphipods may therefore be among the first species to disappear if global temperatures are increased or global oxygen levels decline. Being close to the critical MPS limit may be seen as a specialization that makes giant species more prone to extinction over geological time. Chapelle, Gauthier & Peck, Lloyd S. (May 1999). "Polar gigantism dictated by oxygen availability". Nature. 399 (6732): 114–115. Bibcode:1999Natur.399..114C. doi:10.1038/20099. S2CID4308425.
Westneat et al. 2003: "Insects are known to exchange respiratory gases in their system of tracheal tubes by using either diffusion or changes in internal pressure that are produced through body motion or hemolymph circulation. However, the inability to see inside living insects has limited our understanding of their respiration mechanisms. We used a synchrotron beam to obtain x-ray videos of living, breathing insects. Beetles, crickets, and ants exhibited rapid cycles of tracheal compression and expansion in the head and thorax. Body movements and hemolymph circulation cannot account for these cycles; therefore, our observations demonstrate a previously unknown mechanism of respiration in insects analogous to the inflation and deflation of vertebrate lungs. Westneat, MW; Betz, O; Blob, RW; Fezzaa, K; Cooper, WJ & Lee, WK (January 2003). "Tracheal respiration in insects visualized with synchrotron x-ray imaging". Science. 299 (5606): 558–560. Bibcode:2003Sci...299..558W. doi:10.1126/science.1078008. PMID12543973. S2CID43634044.
Dudley 1998: "Uniformitarian approaches to the evolution of terrestrial locomotor physiology and animal flight performance have generally presupposed the constancy of atmospheric composition. Recent geophysical data, as well as theoretical models, suggest that, to the contrary, both oxygen and carbon dioxide concentrations have changed dramatically during defining periods of metazoan evolution. Hyperoxia in the late Paleozoic atmosphere may have physiologically enhanced the initial evolution of tetrapod locomotor energetics; a concurrently hyperdense atmosphere would have augmented aerodynamic force production in early flying insects. Multiple historical origins of vertebrate flight also correlate temporally with geological periods of increased oxygen concentration and atmospheric density. Arthropod as well as amphibian gigantism appear to have been facilitated by a hyperoxic Carboniferous atmosphere and were subsequently eliminated by a late Permian transition to hypoxia. For extant organisms, the transient, chronic and ontogenetic effects of exposure to hyperoxic gas mixtures are poorly understood relative to the contemporary understanding of the physiology of oxygen deprivation. Experimentally, the biomechanical and physiological effects of hyperoxia on animal flight performance can be decoupled through the use of gas mixtures that vary in density and oxygen concentration. Such manipulations permit both paleophysiological simulation of ancestral locomotor performance and an analysis of maximal flight capacity in extant forms. Dudley, Robert (April 1998). "Atmospheric oxygen, giant Paleozoic insects and the evolution of aerial locomotion performance". The Journal of Experimental Biology. 201 (Pt8): 1043–1050. doi:10.1242/jeb.201.8.1043. PMID9510518.
Chapelle & Peck 1999: "Oxygen supply may also have led to insect gigantism in the Carboniferous period, because atmospheric oxygen was 30-35% (ref. 7). The demise of these insects when oxygen content fell indicates that large species may be susceptible to such change. Giant amphipods may therefore be among the first species to disappear if global temperatures are increased or global oxygen levels decline. Being close to the critical MPS limit may be seen as a specialization that makes giant species more prone to extinction over geological time. Chapelle, Gauthier & Peck, Lloyd S. (May 1999). "Polar gigantism dictated by oxygen availability". Nature. 399 (6732): 114–115. Bibcode:1999Natur.399..114C. doi:10.1038/20099. S2CID4308425.
Westneat et al. 2003: "Insects are known to exchange respiratory gases in their system of tracheal tubes by using either diffusion or changes in internal pressure that are produced through body motion or hemolymph circulation. However, the inability to see inside living insects has limited our understanding of their respiration mechanisms. We used a synchrotron beam to obtain x-ray videos of living, breathing insects. Beetles, crickets, and ants exhibited rapid cycles of tracheal compression and expansion in the head and thorax. Body movements and hemolymph circulation cannot account for these cycles; therefore, our observations demonstrate a previously unknown mechanism of respiration in insects analogous to the inflation and deflation of vertebrate lungs. Westneat, MW; Betz, O; Blob, RW; Fezzaa, K; Cooper, WJ & Lee, WK (January 2003). "Tracheal respiration in insects visualized with synchrotron x-ray imaging". Science. 299 (5606): 558–560. Bibcode:2003Sci...299..558W. doi:10.1126/science.1078008. PMID12543973. S2CID43634044.
Westneat et al. 2003: "Insects are known to exchange respiratory gases in their system of tracheal tubes by using either diffusion or changes in internal pressure that are produced through body motion or hemolymph circulation. However, the inability to see inside living insects has limited our understanding of their respiration mechanisms. We used a synchrotron beam to obtain x-ray videos of living, breathing insects. Beetles, crickets, and ants exhibited rapid cycles of tracheal compression and expansion in the head and thorax. Body movements and hemolymph circulation cannot account for these cycles; therefore, our observations demonstrate a previously unknown mechanism of respiration in insects analogous to the inflation and deflation of vertebrate lungs. Westneat, MW; Betz, O; Blob, RW; Fezzaa, K; Cooper, WJ & Lee, WK (January 2003). "Tracheal respiration in insects visualized with synchrotron x-ray imaging". Science. 299 (5606): 558–560. Bibcode:2003Sci...299..558W. doi:10.1126/science.1078008. PMID12543973. S2CID43634044.
Dudley 1998: "Uniformitarian approaches to the evolution of terrestrial locomotor physiology and animal flight performance have generally presupposed the constancy of atmospheric composition. Recent geophysical data, as well as theoretical models, suggest that, to the contrary, both oxygen and carbon dioxide concentrations have changed dramatically during defining periods of metazoan evolution. Hyperoxia in the late Paleozoic atmosphere may have physiologically enhanced the initial evolution of tetrapod locomotor energetics; a concurrently hyperdense atmosphere would have augmented aerodynamic force production in early flying insects. Multiple historical origins of vertebrate flight also correlate temporally with geological periods of increased oxygen concentration and atmospheric density. Arthropod as well as amphibian gigantism appear to have been facilitated by a hyperoxic Carboniferous atmosphere and were subsequently eliminated by a late Permian transition to hypoxia. For extant organisms, the transient, chronic and ontogenetic effects of exposure to hyperoxic gas mixtures are poorly understood relative to the contemporary understanding of the physiology of oxygen deprivation. Experimentally, the biomechanical and physiological effects of hyperoxia on animal flight performance can be decoupled through the use of gas mixtures that vary in density and oxygen concentration. Such manipulations permit both paleophysiological simulation of ancestral locomotor performance and an analysis of maximal flight capacity in extant forms. Dudley, Robert (April 1998). "Atmospheric oxygen, giant Paleozoic insects and the evolution of aerial locomotion performance". The Journal of Experimental Biology. 201 (Pt8): 1043–1050. doi:10.1242/jeb.201.8.1043. PMID9510518.
Chapelle & Peck 1999: "Oxygen supply may also have led to insect gigantism in the Carboniferous period, because atmospheric oxygen was 30-35% (ref. 7). The demise of these insects when oxygen content fell indicates that large species may be susceptible to such change. Giant amphipods may therefore be among the first species to disappear if global temperatures are increased or global oxygen levels decline. Being close to the critical MPS limit may be seen as a specialization that makes giant species more prone to extinction over geological time. Chapelle, Gauthier & Peck, Lloyd S. (May 1999). "Polar gigantism dictated by oxygen availability". Nature. 399 (6732): 114–115. Bibcode:1999Natur.399..114C. doi:10.1038/20099. S2CID4308425.
Westneat et al. 2003: "Insects are known to exchange respiratory gases in their system of tracheal tubes by using either diffusion or changes in internal pressure that are produced through body motion or hemolymph circulation. However, the inability to see inside living insects has limited our understanding of their respiration mechanisms. We used a synchrotron beam to obtain x-ray videos of living, breathing insects. Beetles, crickets, and ants exhibited rapid cycles of tracheal compression and expansion in the head and thorax. Body movements and hemolymph circulation cannot account for these cycles; therefore, our observations demonstrate a previously unknown mechanism of respiration in insects analogous to the inflation and deflation of vertebrate lungs. Westneat, MW; Betz, O; Blob, RW; Fezzaa, K; Cooper, WJ & Lee, WK (January 2003). "Tracheal respiration in insects visualized with synchrotron x-ray imaging". Science. 299 (5606): 558–560. Bibcode:2003Sci...299..558W. doi:10.1126/science.1078008. PMID12543973. S2CID43634044.
