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There have been both successful and unsuccessful examples of interspecific pregnancy in a multitude of different animals: “alpaca and lama (Godke 2001), cow (Bos taurus) and zebu (Bos indicus; Summers et al. 1983), banteng (Bos javanicus) and cow (Bos taurus; Solti et al. 2000), horse, donkey, Przewalski’s horse and Grant’s zebra (Summers ...
Pregnant male seahorse. Male pregnancy is the incubation of one or more embryos or fetuses by organisms of the male sex in some species. Most species that reproduce by sexual reproduction are heterogamous—females producing larger gametes and males producing smaller gametes ().
The form of the human placenta is generally classified as a discoid placenta. Within this, the cotyledons are the approximately 15-25 separations of the decidua basalis of the placenta, separated by placental septa. [3] Each cotyledon consists of a main stem of a chorionic villus as well as its branches and sub-branches. [3]
Human reproductive biology is primarily controlled through hormones, which send signals to the human reproductive structures to influence growth and maturation.These hormones are secreted by endocrine glands, and spread to different tissues in the human body.
A pregnant lioness. In mammals, pregnancy is the period of reproduction during which a female carries one or more live offspring from implantation in the uterus through gestation. It begins when a fertilized zygote implants in the female's uterus, and ends once it leaves the uterus.
Definition [ edit ] The word pedigree is a corruption of the Anglo-Norman French pé de grue or "crane's foot", either because the typical lines and split lines (each split leading to different offspring of the one parent line) resemble the thin leg and foot of a crane [ 3 ] or because such a mark was used to denote succession in pedigree charts.
The first recorded case of artificial insemination was John Hunter in 1790, who helped impregnate a linen draper's wife. [1] [2] The first reported case of artificial insemination by donor occurred in 1884: William H. Pancoast, a professor in Philadelphia, took sperm from his "best looking" student to inseminate an anesthetized woman without her knowledge.
In 1995, there was a reported case of partial human parthenogenesis; a boy was found to have some of his cells (such as white blood cells) to be lacking in any genetic content from his father. Scientists believe that an unfertilized egg began to self-divide but then had some (but not all) of its cells fertilized by a sperm cell; this must have ...