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Fertilization may take place in the pouch or before implantation in the water. Included in Syngnathidae are seahorses , the pipefish , and the weedy and leafy sea dragons . [ 26 ] Syngnathidae is the only family in the animal kingdom to which the term " male pregnancy " has been applied.
A life history strategy is the "age- and stage-specific patterns" [2] and timing of events that make up an organism's life, such as birth, weaning, maturation, death, etc. [3] These events, notably juvenile development, age of sexual maturity, first reproduction, number of offspring and level of parental investment, senescence and death, depend ...
Human reproduction naturally takes place as internal fertilization by sexual intercourse. During this process, the man inserts his erect penis into the woman's vagina and then either partner initiates rhythmic pelvic thrusts until the man achieves orgasm , which leads to ejaculation of semen containing sperm into the vaginal canal.
Development before birth, or prenatal development (from Latin natalis 'relating to birth') is the process in which a zygote, and later an embryo, and then a fetus develops during gestation. Prenatal development starts with fertilization and the formation of the zygote , the first stage in embryonic development which continues in fetal ...
Fertilization was not understood in antiquity. Hippocrates believed that the embryo was the product of male semen and a female factor. But Aristotle held that only male semen gave rise to an embryo, while the female only provided a place for the embryo to develop, [5] a concept he acquired from the preformationist Pythagoras.
Different terms are used to describe prenatal development, meaning development before birth. A term with the same meaning is the "antepartum" (from Latin ante "before" and parere "to give birth") Sometimes "antepartum" is however used to denote the period between the 24th/26th week of gestational age until birth, for example in antepartum ...
Programmed cell death at the joining surfaces enables fusion to take place. [22] In the middle of the fourth week, the sinus venosus receives blood from the three major veins: the vitelline, the umbilical and the common cardinal veins. During the first two months of development, the interatrial septum begins to form.
A fetus or foetus (/ ˈ f iː t ə s /; pl.: fetuses, foetuses, rarely feti or foeti) is the unborn mammalian offspring that develops from an embryo. [1] Following the embryonic stage, the fetal stage of development takes place.