Book contents
- Frontmatter
- Contents
- Preface
- Contributors
- 1 Maternal diet, maternal proteins and egg quality
- 2 Comparative composition and utilisation of yolk lipid by embryonic birds and reptiles
- 3 Oviductal proteins and their influence on embryonic development in birds and reptiles
- 4 Fluxes during embryogenesis
- 5 Eggshell structure and formation in eggs of oviparous reptiles
- 6 Shell structure and formation in avian eggs
- 7 Physical characteristics of reptilian eggs and a comparison with avian eggs
- 8 Egg-shape in birds
- 9 The thermal energetics of incubated bird eggs
- 10 Physiological effects of incubation temperature on embryonic development in reptiles and birds
- 11 Cold torpor, diapause, delayed hatching and aestivation in reptiles and birds
- 12 Physical factors affecting the water exchange of buried reptile eggs
- 13 Physiological and ecological importance of water to embryos of oviparous reptiles
- 14 Roles of water in avian eggs
- 15 Water economy and solute regulation of reptilian and avian embryos
- 16 The avian eggshell as a mediating barrier: respiratory gas fluxes and pressures during development
- 17 Gas exchange across reptilian eggshells
- 18 Metabolism and energetics of reptilian and avian embryos
- 19 Reasons for the dichotomy in egg turning in birds and reptiles
- 20 A comparison of reptilian eggs with those of megapode birds
- 21 Why birds lay eggs
- 22 Influences of incubation requirements on the evolution of viviparity
- 23 Overview of early stages of avian and reptilian development
- 24 Ions and ion regulating mechanisms in the developing fowl embryo
- 25 Electrochemical processes during embryonic development
- 26 Methods for shell-less and semi-shell-less culture of avian and reptilian embryos
- 27 Experimental studies on cultured, shell-less fowl embryos: calcium transport, skeletal development, and cardio-vascular functions
- Index
17 - Gas exchange across reptilian eggshells
Published online by Cambridge University Press: 16 November 2009
- Frontmatter
- Contents
- Preface
- Contributors
- 1 Maternal diet, maternal proteins and egg quality
- 2 Comparative composition and utilisation of yolk lipid by embryonic birds and reptiles
- 3 Oviductal proteins and their influence on embryonic development in birds and reptiles
- 4 Fluxes during embryogenesis
- 5 Eggshell structure and formation in eggs of oviparous reptiles
- 6 Shell structure and formation in avian eggs
- 7 Physical characteristics of reptilian eggs and a comparison with avian eggs
- 8 Egg-shape in birds
- 9 The thermal energetics of incubated bird eggs
- 10 Physiological effects of incubation temperature on embryonic development in reptiles and birds
- 11 Cold torpor, diapause, delayed hatching and aestivation in reptiles and birds
- 12 Physical factors affecting the water exchange of buried reptile eggs
- 13 Physiological and ecological importance of water to embryos of oviparous reptiles
- 14 Roles of water in avian eggs
- 15 Water economy and solute regulation of reptilian and avian embryos
- 16 The avian eggshell as a mediating barrier: respiratory gas fluxes and pressures during development
- 17 Gas exchange across reptilian eggshells
- 18 Metabolism and energetics of reptilian and avian embryos
- 19 Reasons for the dichotomy in egg turning in birds and reptiles
- 20 A comparison of reptilian eggs with those of megapode birds
- 21 Why birds lay eggs
- 22 Influences of incubation requirements on the evolution of viviparity
- 23 Overview of early stages of avian and reptilian development
- 24 Ions and ion regulating mechanisms in the developing fowl embryo
- 25 Electrochemical processes during embryonic development
- 26 Methods for shell-less and semi-shell-less culture of avian and reptilian embryos
- 27 Experimental studies on cultured, shell-less fowl embryos: calcium transport, skeletal development, and cardio-vascular functions
- Index
Summary
Introduction
In contrast to the open nests of birds, nests of reptiles are generally located in the soil or in decaying vegetation where, effectively separated from the atmospheric gaseous environment, eggs may be exposed to relatively low partial pressures of oxygen and correspondingly high partial pressures of carbon dioxide (Ackerman, 1977; Seymour & Ackerman, 1980; Ferguson, 1985; Packard & Packard, 1988). The deviation from atmospheric oxygen and carbon dioxide tensions may be greater during the later stages of incubation due to a high rate of respiration of the embryos (Booth & Thompson, Chapter 20). In addition, the humidity of these nests is high. Consequently, problems of desiccation are reduced thereby allowing eggs to have high conductances to respiratory gases which result in smaller gradients of respiratory gases across the eggshell. These presumably help to maintain the internal gaseous environment within physiological limits even in nests with low oxygen and high carbon dioxide tensions (Booth & Thompson, Chapter 20). In this chapter, we discuss conductance of different types of reptilian eggshell to water and to respiratory gases, making comparisons, where possible, with avian eggs. As eggshell structure is highly variable (Packard & DeMarco, Chapter 5) conductance and allometric relationships are described separately for each major type of shell.
The eggshell as a mediating barrier
Water vapour
In avian eggs, water vapour, oxygen and carbon dioxide all diffuse across the eggshell through the same pathway – discrete pores in the calcareous eggshell; the relative conductance of the shell to these gases is related to their different rates of diffusion (Paganelli, Ackerman & Rahn, 1978).
- Type
- Chapter
- Information
- Egg IncubationIts Effects on Embryonic Development in Birds and Reptiles, pp. 277 - 284Publisher: Cambridge University PressPrint publication year: 1991
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