This essay will discuss the origins of parthenogenesis, the advantages and disadvantages and its effects on nature. (1.1 c)

The Encyclopaedia of Genetics (2001) describes parthenogenesis as “the production of an embryo from a female gamete without any genetic contribution from a male gamete, with or without the eventual development into an adult.” Parthenogenesis can also be described as A-sexual or self-reproduction. It is also referred to as ‘virgin birth’ (1.1 d ,3.1 b).

Parthenogenesis is commonly found in organisms such as plants and insects. The occurrence has rarely been seen in any mammal however, when it has, the animal lacks certain qualities and genetic diversities of a mammal conceived through sexual reproduction. (2. 2) According to Encyclopaedia Britannia (2018), Parthenogenesis occurs commonly among lower plants and invertebrate animals (particularly rotifers, aphids, ants, wasps, and bees) and rarely among higher vertebrates. (1.1 b,1.1 c 1.1 d). When discussing parthenogenic insects we can refer to them as a-sexual beings , however when speaking about parthenogenic plants/seeds, it is more accurate to discuss them as being agamospermy or apomictic organisms . (1.1 b, 1.1 d ,3.1 a,3.1 b)

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Parthenogenesis is an adaptive strategy that allows organisms to reproduce when sexual reproduction is not possible due to environmental conditions. – Regina Bailey (2016) . (1.1 a,1.1 d). This creates an understanding that parthenogenesis has become an evolutionary trait to allow organisms to reproduce when faced with factors that hinders their usual form of reproduction. In a time of crisis when reproduction is critical to prevent extinction, parthenogenesis helps to preserve life due to their ability to produce offspring rapidly. Some organisms need this evolutionary trait as they may lack a partner in which to sexually reproduce therefore are able to continue the species without the presence of a male. Parthenogenesis is not always a positive trait and may prevent the organism’s ability to survive in a modern environment due to lack of genetic diversity. Another advantage of parthenogenesis over sexual reproduction, is that sexual reproduction is more time consuming and therefore results in few off spring. (1.1 b, 1.1 d, 2.2, 3.1 a)

Parthenogenesis also has many disadvantages. Regina Bailey (2016) believes that “a disadvantage of this type of reproduction is the lack of genetic variation. There is no movement of genes from one population to another.”  Various survival genes not being passed on to the next generation causes of deprivation of evolutionary skills such as; ability to live on land and the ability to fly. It also hinders the next generation from developing further survival skills which organisms produced through sexual reproduction may have. This results in parthenogenic organisms not being as advanced as other organisms therefore possibly having a lower survival rate. Plants also need genetic variation in order to survive in harsh weather and animal habitats. Therefore, it is vital humans cannot produce parthenogenically, as it would result in humans regressing on the evolutionary scale rather than progressing.  (1.1 b, 1.1 d ,3.1 a)

Medical hypotheses (2017) explains that “spontaneous parthenogenetic and androgenetic events occur in humans, but they result in tumours: the ovarian teratoma and the hydatidiform mole”. Teratoma’s usually consist of hair, teeth, muscle and bone. They are also present before birth and can be found in the ovaries or testicles. Small teratoma’s can mainly be presented as a small lump and cause little to no pain. However larger teratoma’s can cause serious complications and need to be surgically removed. Hydatidiform moles are fertilised eggs which grow in the womb, they can either be a collection of cells with no foetal resemblance or they can be ‘partial moles’ which means it is an abnormal foetus which begins to form but cannot survive or grow into a baby. (1.1 a , 1.1 b, 1.1 c , 2.2 , 3.1 b)

In conclusion parthenogenesis has both advantages and disadvantages. It also has a great effect on nature and evolution. Many researchers believe parthenogenesis to be a ‘phenomenon’ and continue to research into the potential of a-sexual reproduction in mammals. Many experiments have been carried out with no positive result so far. ( 2.2 , 3.1 a , 3.1 b , 4.1 )

Bibliography / references

Cited in Ferguson smith A.C, Encyclopaedia of Genetics 2001  2096-2099

The Editors of Encyclopaedia Britannica 2018 Parthenogenesis Encyclopaedia Britannica https://www.britannica.com/science/parthenogenesis (Access Date: July 22, 2019)

Bailey, R. “What Is Parthenogenesis?” ThoughtCo. https://www.thoughtco.com/parthenogenesis-373474 (accessed July 22, 2019).

Cited in Medical Hypotheses September 2017, Volume 106  Pages 57-60

Lynch M, Gabriel E , “Phenotypic Evolution and Parthenogenesis,” The American Naturalist 122, no. 6 (Dec., 1983): 745-764.  https://doi.org/10.1086/284169. Accessed 27 /07/ 2019

Bierzychudek, P. Experientia (1985) 41: 1255. https://doi.org/10.1007/BF01952068 /   Accessed 27 / 07 / 2019