User:Nestad1/sandbox
Look to the double fertilization page for the most recent draft. The one in this sandbox may not be the same.
Article Evaluation[edit]
Double fertilization is wikipedias article focused on the fertilization events that occur in angiosperms. The page is rated as Start-Class and Mid-Importance within the WikiProject Plants. The origin of the double fertilization event that occurs in angiosperms has been held in high regard by biologists to help determine the correct phylogeny that connects gymnosperms and angiosperms. In the summary section at the start of the article, the connection between double fertilization in angiosperms and isolated cases in Gnetales is stated, but not explained. I seek to collect evidence from a multitude of sources through Google Scholar to expand on the origin of this double fertilization event in gymnosperms and to relate it to the common event that takes place across almost all of angiosperms.
Double Fertilization in Gymnosperms[edit]
A far more rudimentary form of double fertilization occurs in the sexual reproduction of an order of gymnosperms commonly known as Gnetales.[1] Specifically, this event has been documented in both Ephedra and Gnetum, a subset of Gnetophytes.[2] In Ephedra nevadensis, a single binucleate sperm cell is deposited into the egg cell. Following the initial fertilization event, the second sperm nucleus is diverted to fertilize an additional egg nucleus found in the egg cytoplasm. In most other seed plants, this second 'ventral canal nucleus' is normally found to be functionally useless.[3] In Gnetum gnemon, numerous free egg nuclei exist in female cytoplasm inside the female gametophyte. Succeeding the penetration of the mature female gametophyte by the pollen tube, female cytoplasm and free nuclei move to surround the pollen tube. Released from the binucleate sperm cell are two sperm nuclei which then join with free egg nuclei to produce two viable zygotes, a homologous characteristic between families Ephedra and Gnetum.[4] In both families, the second fertilization event produces an additional diploid embryo. This supernumerary embryo is later aborted, leading to the synthesis of only one mature embryo.[5] The additional fertilization product in Ephedra does not nourish the primary embryo, as the female gametophyte is responsible for nutrient provision.[4] The more primitive process of double fertilization in gymnosperms results in two diploid nuclei enclosed in the same egg cell. This differs from the angiosperm condition, which results in the separation of the egg cell and endosperm.[6] Comparative molecular research on the genome of the members of Gnetales has revealed that gnetophytes are more closely related to conifers than they are to angiosperms.[7][8][9] The rejection of the anthophyte hypothesis, which identifies gnetales and angiosperms are sister taxa, leads to speculation that the process of double fertilization is a product of convergent evolution and arose independently among gnetophytes and angiosperms.[10]
Response to Peer Review[edit]
Taking the peer review into heavy consideration, I have attempted to simplify a large portion of my draft. I mainly focused on the statements that pertain to information found from scientific studies in an attempt to reach an audience that possibly does not have all of the knowledge of plant biology that our class has. This also serves the purpose of creating a less 'dry' tone by removing needless scientific jargon. I am currently working on trying to spread out some of the information by possibly creating a 'Morphological Data' section. The only issue with this endeavor is that I believe I would be over-saturating a page originally intended to give information on the general idea of double fertilization. I may end up removing my last two statements from the draft because I feel they go way past the intent of the original wiki article.----This draft will be fitting in to the last paragraph of the summary of the article. Looking back, it may be smart to start a new heading on the page right after the 'Brief History' section.
I have posted for feedback in the talk page of the article. No one responded, looks like they're getting this whether they like it or not.
Update[edit]
I have decided on the placement of my draft into the article. My heading will be placed below the 'Brief history' segment and above the 'In vitro double fertilization' segment. I have further cleaned up the paragraph to remove some of the dull scientific terminology to make this more legible to people without a background in plant biology. I'm not sure how much more the wording and information can be changed to elicit the same material while still remaining relevant to my personal goals with this project. I am not posting the entirety of this draft into the talk page with hopes to garner some sort of attention and assistance from the Wikipedia community.
Sources[edit]
- ^ Raghavan, V. (2003-09-01). "Some reflections on double fertilization, from its discovery to the present". New Phytologist. 159 (3): 565–583. doi:10.1046/j.1469-8137.2003.00846.x. ISSN 1469-8137.
- ^ Carmichael, J. S.; Friedman, W. E. (1995-12-01). "Double Fertilization in Gnetum gnemon: The Relationship between the Cell Cycle and Sexual Reproduction". The Plant Cell. 7 (12): 1975–1988. doi:10.1105/tpc.7.12.1975. ISSN 1040-4651. PMID 12242365.
- ^ Friedman, William E. (1990). "Sexual Reproduction in Ephedra nevadensis (Ephedraceae): Further Evidence of Double Fertilization in a Nonflowering Seed Plant". American Journal of Botany. 77 (12): 1582–1598. doi:10.2307/2444491.
- ^ a b Carmichael, Jeffrey S.; Friedman, William E. (1996). "Double Fertilization in Gnetum gnemon (Gnetaceae): Its Bearing on the Evolution of Sexual Reproduction within the Gnetales and the Anthophyte Clade". American Journal of Botany. 83 (6): 767–780. doi:10.2307/2445854.
- ^ Friedman, W. E. (1995-04-25). "Organismal duplication, inclusive fitness theory, and altruism: understanding the evolution of endosperm and the angiosperm reproductive syndrome". Proceedings of the National Academy of Sciences. 92 (9): 3913–3917. doi:10.1073/pnas.92.9.3913. ISSN 0027-8424. PMID 11607532.
- ^ Friedman, William E. (1994). "The Evolution of Embryogeny in Seed Plants and the Developmental Origin and Early History of Endosperm". American Journal of Botany. 81 (11): 1468–1486. doi:10.2307/2445320.
- ^ Bowe, L. Michelle; Coat, Gwénaële; dePamphilis, Claude W. (2000-04-11). "Phylogeny of seed plants based on all three genomic compartments: Extant gymnosperms are monophyletic and Gnetales' closest relatives are conifers". Proceedings of the National Academy of Sciences. 97 (8): 4092–4097. doi:10.1073/pnas.97.8.4092. ISSN 0027-8424. PMID 10760278.
- ^ Winter, Kai-Uwe; Becker, Annette; Münster, Thomas; Kim, Jan T.; Saedler, Heinz; Theissen, Günter (1999-06-22). "MADS-box genes reveal that gnetophytes are more closely related to conifers than to flowering plants". Proceedings of the National Academy of Sciences. 96 (13): 7342–7347. doi:10.1073/pnas.96.13.7342. ISSN 0027-8424. PMID 10377416.
- ^ Magallon, S.; Sanderson, M. J. (2002-12-01). "Relationships among seed plants inferred from highly conserved genes: sorting conflicting phylogenetic signals among ancient lineages". American Journal of Botany. 89 (12): 1991–2006. doi:10.3732/ajb.89.12.1991. ISSN 1537-2197.
- ^ Chaw, Shu-Miaw; Parkinson, Christopher L.; Cheng, Yuchang; Vincent, Thomas M.; Palmer, Jeffrey D. (2000-04-11). "Seed plant phylogeny inferred from all three plant genomes: Monophyly of extant gymnosperms and origin of Gnetales from conifers". Proceedings of the National Academy of Sciences. 97 (8): 4086–4091. doi:10.1073/pnas.97.8.4086. ISSN 0027-8424. PMID 10760277.
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