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Bateman attributed the origin of the unequal investment to the differences in the production of gametes: sperm are cheaper than eggs. A single male can easily fertilize all of a female's eggs; she will not produce more offspring by mating with more than one male. A male is capable of fathering more offspring if he mates with several females.
A 1992 World Health Organization report described normal human semen as having a volume of 2 mL or greater, pH of 7.2 to 8.0, sperm concentration of 20×10 6 spermatozoa/mL or more, sperm count of 40×10 6 spermatozoa per ejaculate or more, and motility of 50% or more with forward progression (categories a and b) of 25% or more with rapid ...
Sperm storage organs in the fruit fly Drosophila melanogaster.Female was first mated with GFP-male and then re-mated with RFP-male. Female sperm storage is a biological process and often a type of sexual selection in which sperm cells transferred to a female during mating are temporarily retained within a specific part of the reproductive tract before the oocyte, or egg, is fertilized.
The sperm are transferred from the pollen through the pollen tube to the ovule where the egg is fertilised. In flowering plants, two sperm cells are released from the pollen tube, and a second fertilisation event occurs involving the second sperm cell and the central cell of the ovule, which is a second female gamete. [7]
The production of female offspring by parthenogenesis is referred to as thelytoky (e.g., aphids) while the production of males by parthenogenesis is referred to as arrhenotoky (e.g., bees). When unfertilized eggs develop into both males and females, the phenomenon is called deuterotoky. [22]
“Adding protein or fat with fruit helps with satiation and can help lead to more balanced blood sugar levels,” says Sue-Ellen Anderson-Haynes, M.S., R.D.N., founder of 360Girls&Women. “For ...
In 2007, a patent application was filed [6] on methods for creating human female sperm using artificial or natural Y chromosomes and testicular transplantation. [2] Key to successful creation of female sperm (and male eggs ) will be inducing male epigenetic markings for female cells that initially have female markings, with techniques for doing ...
Durov said in July that he has fathered more than 100 children over 15 years of sperm donation. Pavel Durov, the billionaire CEO of Telegram, funded fertility treatment for women using his sperm ...