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
8 - Egg-shape in birds
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
The egg of a bird can be envisaged as a naturally occuring organ culture which, given sufficient heat and oxygen, allows the original single cell to transform the acellular substrate into a complex multicellular animal. The feature of the system which concerns us in this chapter is the calcareous shell which imparts a fixed shape to this system. A typical avian egg presents to the eye a regular profile, symmetrical about its long axis with one end more pointed than the other yet this shape has been strangely difficult to characterise mathematically. An equation describing egg curvature is useful as a shape descriptor and for understanding the forces which give rise to the ovoid form. Also, since an egg is axisymmetric, an equation that can be solved from simple linear measurements allows the volume and surface area of the solid of revolution generated by its profile to be calculated by integration (Paganelli, Olszowka & Ar, 1974).
Egg volume and surface area are rather special parameters as they are constants of the system. It is remarkable that a given volume of organic molecules, constituting a new-laid egg, is constrained within an envelope of constant area through which all respiratory exchanges must be conducted. This predetermined surface area, established when only one diploid nucleus is present, must eventually be compatible with mediating the gaseous transfer required by the many millions of aerobically respiring cells of the embryo (Paganelli, Chapter 16).
- Type
- Chapter
- Information
- Egg IncubationIts Effects on Embryonic Development in Birds and Reptiles, pp. 101 - 116Publisher: Cambridge University PressPrint publication year: 1991
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