title: Evolution of avian eggshell structure.
abstract: Data are presented suggesting that birds have evolved eggs with shells containing different structures (numbers of mammillae per unit of inner eggshell surface area, i.e., mammillary densities) to cope up with different calcium requirements imposed by different growth rates and modes of development. Precocial bird species grow slowly, but have high mammillary density, while altricial bird species grow rapidly, but have low mammillary density. These results suggest an adaptation associated with growth rate and mode of development and show, moreover, that the mammillary layer is indicative of the breeding biology of the bird.
authors: School of Natural Sciences, Linnaeus University, Kalmar, Sweden.
authors: Ola
authors: O
authors: Osterström
authors: Clas
authors: C
authors: Lilja
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D005075:Biological Evolution; D001717:Birds / Q000254:growth & development* / Q000502:physiology; D001947:Breeding; D002118:Calcium / Q000378:metabolism; D004528:Egg Shell / Q000737:chemistry / Q000648:ultrastructure*
chemical_list: D002118:Calcium