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Parthenogenesis is a mode of asexual reproduction in which offspring are produced by females without the genetic contribution of a male. Among all the sexual vertebrates, the only examples of true parthenogenesis, in which all-female populations reproduce without the involvement of males, are found in squamate reptiles (snakes and lizards). [1]
Mucor (short for Mucormycosis) is a microbial genus of approximately 40 species of molds in the family Mucoraceae. [ 1 ] [ 2 ] Species are commonly found in soil , digestive systems , plant surfaces, some cheeses like Tomme de Savoie , rotten vegetable matter and iron oxide residue in the biosorption process.
Asexual reproduction often occurs continuously. In heterothallic species, sexual reproduction occurs when opposite mating types (designated + and -) come into close proximity, inducing the formation of specialized hyphae called gametangia. The gametangia grow toward each other, then fuse, forming a diploid zygote at the point of fusion.
Asexual reproduction is found in nearly half of the animal phyla. [57] Parthenogenesis occurs in the hammerhead shark [ 58 ] and the blacktip shark . [ 59 ] [ 60 ] In both cases, the sharks had reached sexual maturity in captivity in the absence of males, and in both cases the offspring were shown to be genetically identical to the mothers.
A form of asexual reproduction related to parthenogenesis is gynogenesis. Here, offspring are produced by the same mechanism as in parthenogenesis, but with the requirement that the egg merely be stimulated by the presence of sperm in order to develop. However, the sperm cell does not contribute any genetic material to the offspring.
The hemipenis is the intromittent organ of Squamata, [4] which is the second largest order of vertebrates with over 9,000 species distributed around the world. They differ from the intromittent organs of most other amniotes such as mammals, archosaurs and turtles that have a single genital tubercle, as squamates have the paired genitalia remaining separate. [5]
Sexual reproduction in Glomeromycotina is unknown, although its occurrence is inferred from genomic studies. However, specialized hyphae produce chlamydospore-like spores asexually; these may be borne at terminal (apical) or lateral positions on the hyphae, or intercalary (formed within the hypha, between sub-apical cells). [ 8 ]
The description of its habit was based on Andreas Cleyer, who in 1684 described a gigantic snake that crushed large animals by coiling around their bodies and crushing their bones. [8] Henry Yule in his 1886 work Hobson-Jobson , notes that the word became more popular due to a piece of fiction published in 1768 in the Scots Magazine by a ...