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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 36 weeks. The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is completed in the uterus.
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, [10] intention to have children, [11] and maternal support. [12] Factors generally associated with decreased fertility include wealth , education, [ 13 ] [ 14 ] female labor participation , [ 15 ] urban residence, [ 16 ] cost of housing , [ 17 ] [ 18 ] intelligence ...
Many studies have attempted to determine the causal link between government policies and fertility. However, as this article suggests, there are many factors that can potentially affect decisions to have children, how many to have, and when to have them, and separating these factors from effects of a particular government policy is difficult.
[5] [6] [7] Even after differentiation can be seen between the sexes, some stages are common, e.g. the disappearing of the membrane. On the other hand, sex-dependent development include further protrusion of the genital tubercle in the male to form the glans and shaft of the penis and in the female, the glans and body of the clitoris.
Plant development is the process by which structures originate and mature as a plant grows. It is studied in plant anatomy and plant physiology as well as plant morphology. Plants constantly produce new tissues and structures throughout their life from meristems [ 36 ] located at the tips of organs, or between mature tissues.
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 ...