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These factors likely contribute to reduced reproductive success by males of advanced age. The Blurnton-Jones 'backload model' "tested a hypothesis that the length of the birth intervals of !Kung hunter-gatherers allowed women to balance optimally the energetic demands of child bearing and foraging in a society where women had to carry small ...
Human embryology is the study of this development during the first eight weeks after fertilization. The normal period of gestation (pregnancy) is about nine months or 40 weeks. The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is completed in the uterus.
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 ...
There are a multitude of factors that potentially affect the rates of fecundity. For example: ontogeny, population density and latitude. Ontogeny. Fecundity in iteroparous organisms often increases with age but can decline at older ages. Several hypotheses have been proposed to explain this relationship.
Factors generally associated with increased fertility include religiosity, [9] intention to have children, [10] and maternal support. [11] Factors generally associated with decreased fertility include wealth , education, [ 12 ] [ 13 ] female labor participation , [ 14 ] urban residence, [ 15 ] cost of housing, [ 16 ] [ 17 ] intelligence ...
Environmental factors affecting development may include both diet and disease exposure, as well as social, emotional, and cognitive experiences. [56] However, examination of environmental factors also shows that children can survive a fairly broad range of environmental experiences. [55]
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 ...
It is determined by multiple factors including genetic, environmental, hormonal, nutritional and psychosocial factors. Some factors, such as maternal nutrition and alcohol, tobacco and drug exposure affect size at birth while other factors, such as genetic syndromes and family members heights have a later influence on size. [3]