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Internal fertilization evolved many times in animals. [2]: 2 According to David B. Dusenbery all the features with internal fertilization were most likely a result from oogamy. [7] It has been argued that internal fertilization evolve because of sexual selection through sperm competition. [8]
In zoology, copulation is animal sexual behavior in which a male introduces sperm into the female's body, especially directly into her reproductive tract. [ 1 ] [ 2 ] This is an aspect of mating . Many aquatic animals use external fertilization , whereas internal fertilization may have developed from a need to maintain gametes in a liquid ...
Fertilization is the fusion of two gametes. [1] Copulation is the union of the sex organs of two sexually reproducing animals for insemination and subsequent internal fertilization. [2] Mating may also lead to external fertilization, as seen in amphibians, fishes and plants. For most species, mating is between two individuals of opposite sexes.
One organism will inseminate the other, with the inseminating individual being the father. The sperm is absorbed through pores or sometimes wounds in the skin from the partner's stylet, causing fertilization in the other, who becomes the mother. [3] [4] [5] The battle may last for up to an hour in some species. [6]
(True) oviparity, in which fertilization is internal, is taken to be the derived condition, whether the male injects the sperm into the female intromittently or whether she actively or passively picks it up — the female lays eggs containing zygotes with a substantial quantity of yolk to feed the embryo while it remains in the egg, and in many ...
Most cephalopods use semi-internal fertilization where the male places his gametes inside the female's mantle cavity to fertilize the ova in the female's single ovary. [61] The "penis" in most male cephalopods is a long and muscular end of the gonoduct used to transfer spermatophores to a modified sperm-carrying arm called a hectocotylus. That ...
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.
Birds are one of the only groups which reproduce through internal fertilization but have repeatedly lost the intromittent organ. [29] Male ostriches have a conical shaped penis that is wider at the base. [30] A functional intromittent organ is known to be present in most species of Paleognathae and Anseriformes. [26]