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The term fecundity in population biology is often used to describe the rate of offspring production after one time step (often annual). In this sense, fecundity may include both birth rates and survival of young to that time step. While levels of fecundity vary geographically, it is generally a consistent feature of each culture.
Fecundity selection, also known as fertility selection, is the fitness advantage resulting from selection on traits that increases the number of offspring (i.e. fecundity). [1] Charles Darwin formulated the theory of fecundity selection between 1871 and 1874 to explain the widespread evolution of female-biased sexual size dimorphism (SSD ...
In demographic contexts, fertility refers to the actual production of offspring, rather than the physical capability to reproduce, which is termed fecundity. [1] [2] [3] The fertility rate is the average number of children born during an individual's lifetime.
Fertilization was not understood in antiquity. Hippocrates believed that the embryo was the product of male semen and a female factor. 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.
A gamete (/ ˈ ɡ æ m iː t /; from Ancient Greek γαμετή (gametḗ) 'wife', ultimately from Ancient Greek γάμος (gámos) 'marriage') is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. [1] Gametes are an organism's reproductive cells, also referred to as sex cells. [2]
This is an accepted version of this page This is the latest accepted revision, reviewed on 4 February 2025. Union of opposite-sex gametes in sexual reproduction to form a zygote This article is about fertilisation in animals and plants. For fertilisation in humans specifically, see Human fertilization. For soil improvement, see Fertilizer. "Conceive" redirects here. For the health magazine ...
Anisogamy is the form of sexual reproduction that involves the union or fusion of two gametes which differ in size and/or form. [12] The smaller gamete is considered to be male (a sperm cell), whereas the larger gamete is regarded as female (typically an egg cell, if non-motile).
The zygote is the earliest developmental stage. In humans and most other anisogamous organisms, a zygote is formed when an egg cell and sperm cell come together to create a new unique organism. The formation of a totipotent zygote with the potential to produce a whole organism depends on epigenetic reprogramming.