EEB386H1 Lecture Notes - Lecture 9: Brood Parasite, Cing, Water Vapor
14 Aug 2014
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Just add heat and oxygen ! All vertebrate taxa have members which lay eggs (even mammals, the montremes) but birds only reproduce this way (exclusively oviparous) Birds are also unusual in being iteroparous; there are no one- off semelparous species. The bird egg is a self- contained life support system for the developing embryo. Females lack a functional right oviduct, and most males lack a functional penis, or at least one capable of intromission. The male reproductive system consists of paired testis and ductus deferens which transport sperm to the cloaca. The cloaca is a common chamber where urinary, reproductive and gastrointestinal products collect before exiting the vent (anus) Most birds (97%) lack an intromittent phallus (penis) and instead have a swelling on the inside of the vent. Copulation in most species comprises cloacal to cloacal contact. In most, but not all, species the adult females have a functional left ovary and oviduct.
