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Dillon Flint 14 Sept 2014

Topic: What caused the platypus to continue to lay eggs, develop a venomous component (and its purpose), and continue to survive today?

Warren, Wesley, et al. “Genome Analysis of the platypus reveals unique signatures of evolution.” Nature 453 (8 May 2008): 175-183. Web. 14 September 2014. <doi:10.1038/nature06936>

The platypus has always been known as an interesting animal due to its unique body structure. However, scientists have been attempting to classify for years. The animal lays eggs like a reptile, yet still has mammary glands for the underdeveloped young (175). Also, the monotreme has a venom delivery system unique to any types of mammals and sexually selective to males (175). Lactation has improved contrary to previous egg production, meaning milk has increased its nutrient benefit toward offspring (much different from just egg-laying animals) (178).

Whittington, Camilla, et al. ”Defensins and the convergent evolution of platypus and reptile venom genes.” Genome Research 18 (7 May 2008): 986-994. Web. 14 September 2014. <doi:10.1101/gr.7149808>

The platypus has been seen as a myth or made up animal differing from any other animal on earth. It has the capability to lay eggs and lactate. One special feature on this animal is its venom spur. Most people would see this as a defensive weapon, however, it has been observed most likely to serve as an offensive weapon to convey dominance during breeding season (987). Injection of venom has immediate pain and discomfort in humans and is not easily alleviated from most anesthetics (987). Platypus venom has independently evolved from reptile venom (991).

Veyrunes, Frédéric, et al. “Bird-like sex chromosomes of platypus imply recent origin of a mammal sex chromosomes.” Genome Research 18 (7 May 2008): 965-973. Web. 13 September 2014. <doi:10.1101/gr.7101908>

Monotremes have an extremely complex sex-determining gene complex dealing with 10 (5 X and 5 Y chromosomes). This has shown that their homology is more like a birds genetic mapping unlike previously reported to be like mammals (966). This means the divergence occurred 166 million years ago.

Ordoñez, Gonzalo, et al. “Loss of gene implicated in gastric function during platypus evolution.” Genome Biology 9: (15 May 2008): 1-11. Web. 14 September 2014. <genomebiology.com/2998/9/4/R81>

The absence of pepsinogen and gene encoding gastrin have been observed within the platypus genome which is similar to fish, therians, and chickens. Many things seem to distinguish the platypus from mammals and make it a mixture of many other species. One hypothesis is that the loss of the gastric genes have had an advantage against pathogens (which rely on high pH levels) (6). How could this be to bring them to higher survival rates. These small mammals have a mixture of species yet have selective advantage through some evolutionary traits.

Retief, Jacques, et al. “Evolution of the Monotremes.” Department of Medical Biochemistry 218 (7 September 1993): 457-461. Web. 14 September 2014. http://onlinelibrary.wiley.com/doi/10.1111/j.1432-1033.1993.tb18396.x/pdf

Much of the evolution of monotremes resembles closeness to birds. The sperm has grown in length much like birds and so do their reproductive characteristics. However, their soft fur and ability to lactate to feed the young resemble mammals, much of its reproduction is similar to birds. The protamine P1 genes have unique similarities and allow for the relationships between eutherian mammals, marsupials, and birds to be observed.

Suggestions, Citations, and Edit

Edit plus citation https://en.wikipedia.org/wiki/Platypus_venom "which secrete venom that is only seasonally active to breeding season, supporting the theory that the use of venom is for competition of mates only, not protection. While the spur remains out of breeding season, the platypus's venom gland lacks secretion" </ref>Whittington, Camilla, et al. ”Defensins and the convergent evolution of platypus and reptile venom genes.” Genome Research 18 (7 May 2008): 986-994. Web. 14 September 2014. <doi:10.1101/gr.7149808></ref>

And my 3 suggestion occurred on the main page: https://en.wikipedia.org/wiki/Talk:Platypus Mating and Venom[edit] Could anyone further explain how the venom actually affects platypus to platypus contact? I realize it states that venom production increases during mating season but how does the venom affect each other apart from other small animals?

How is reproduction achieved? I have read up on the echidna, and they have four penises for reproduction (only two ejaculate on opposing sides while alternating during mating).[1] Since monotremes are one break away from echidna, how does the platypus mate?

Mating season seems to be concrete; however, I have found an article where individual adult females breed randomly throughout the mating season. Would this be able to enlighten reproductive success?

Flint.39 (talk) 16:33, 1 October 2014 (UTC)Dillon Flint Over the past couple of weeks, I have been hoping for a response or some sort of suggestion to the questions I posted and the change that I have made but nothing seems to be catching anyone's attention. I don't know what else I should do. Just providing some feedback upon waiting for something to happen. Flint.39 (talk) 01:16, 13 October 2014 (UTC)Dillon Flint

I am still waiting to have any discussion for my post on Platypus venom and my discussion on the overall platypus page.  Nothing seems to be happening.  I am being told that reviews are severely backlogged, and it may take a month for anything to happen.  Thanks.  Flint.39 (talk) 13:46, 28 October 2014 (UTC)Dillon Flint
Your recent article submission to Articles for Creation has been reviewed! Unfortunately, it has not been accepted at this time. The reason left by 78.26 was: Please check the submission for any additional comments left by the reviewer. You are encouraged to edit the submission to address the issues raised and resubmit when they have been resolved. 78.26 (spin me / revolutions) 19:35, 3 November 2014 (UTC)[reply]


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Hello! Flint.39, I noticed your article was declined at Articles for Creation, and that can be disappointing. If you are wondering or curious about why your article submission was declined please post a question at the Articles for creation help desk. If you have any other questions about your editing experience, we'd love to help you at the Teahouse, a friendly space on Wikipedia where experienced editors lend a hand to help new editors like yourself! See you there! 78.26 (spin me / revolutions) 19:35, 3 November 2014 (UTC)[reply]


Final Paper Starts Here

Platypus: Its Place and Evolutionary Survival An animal that has hair like a mammal, lays eggs like a bird, and venom like a reptile may seem like a myth or a hoax; however, this animal not only exists but thrives (Rosalind et al., 2000). The platypus seems to be in an evolutionary transition between mammals and reptiles; yet, it continues to survive today. Where did it come from? How has it continued to survive while remaining morphologically unchanged? What behaviors or adaptations have led its high fitness and reproductive success? Being a few of the questions that need to be answered, the platypus contains crucial information in the evolution of mammals, while its continued survival iterates its importance to be understood. Upon answering the first question of where did the platypus originate, mammals diverged from reptiles around 300 million years ago which break up into three groups: monotremes, marsupials, and eutherians. Previously, monotremes were considered part of the same clade as marsupials but have recently been separated. In order to find this distinction, scientists have used genetic imprinting (expression of one parental allele) of the “insulin-like growth factor 2 (Igf2)” which is present in marsupials; yet, monotremes are lacking. This deviation supports the hypothesis of monotremes being the earliest mammalian form (Rosalind et al., 2000). Another method of taxon sampling or DNA sequencing of mitochondrial genomes have once again affirmed the molecular clock and placement of monotremes as the base of the mammalian tree (van Rheede et al., 2005). This distinction of monotremes as the basis of all mammals conveys their importance in understanding the evolutionary history of the platypus, but what other differences keep them from being classified as eutherians and marsupials? In order to further understand the evolution of monotremes, many scientists turn to DNA mapping. With the improved technology, scientists have been using DNA and genetic mapping in order to further understand the relationships between groupings of animals. With the theory of monotremes as the transition order between mammals and reptiles/birds, this makes them a good candidate to study. Upon further mapping, the importance of introns in the DNA sequence containing the “6-9 cysteine residues in the protein sequence (P1 gene)” (Jacques et al., 1993) can verify placements of proamines and eutherian mammals. If an organism lacks this P1 gene, then an animal is defined as a true proamine (fish, reptiles, and marsupials), while eutherian mammals contain it. The presence of this gene allows sperm nuclei to become more stable through “intramolecular disulfide bridges” (Jacques et. al, 1993). Through phylogenetics and the bootstrapped parsimony method, monotremes were discovered to contain similar genes as the P1 but lack the cysteine 6-9. Through parsimony, the monotremes, including the platypus, are equidistant from birds/reptiles and mammals, strengthening the importance of the monotreme as an evolutionary transition. Although DNA mapping illuminates genetic similarity, many physical traits convey their transition and importance. The defining physical characteristics conveying the divergence of mammals from reptiles was the development of homeothermy (hair growth) and lactation which happened around 300 million years ago. These qualities were carried on through primitive mammals. Another divergence occurred around 165 million years ago between the prototherians (where monotremes reside) and therians (where marsupials and eutherians reside); however, the monotremes became more of a transition group by keeping similar attributes of birds, reptiles, and mammals (Warren et al., 2008). Reptiles lack hair while mammals have acquired it since mammals are warm blooded, which coincides to the platypus since it is warm blooded and has hair. Through the divergence of reptiles to mammals, monotremes have kept physical features of both groups. The importance of the platypus and monotremes as an evolutionary transition becomes extremely evident through their mating sexual determination. In therian animals, sex determination occurs between an XX female and an XY male arrangement; on the other hand, birds and reptiles use a ZW female: ZZ male system in which the amount of Z affects male determination (Veyrunes et al., 2008). Being the most recent divergence between mammals and reptiles, the platypus shares a similar system of sex determination by using 10 chromosomes (X and Y) making five pairs in which the dosage of Y determines if the offspring become a male (Rens et al., 2010). This system of dosage and multiple sex chromosome differentiation is more closely related to birds rather than mammals which illustrates this transition state mentality between mammals, reptiles, and birds. Sex determination chromosomes and dosages highlight the transition state of monotremes but egg laying conveys a tangible and physical characteristic of their jointed ancestry. Rather than live birth like other mammals, the platypus has a unique reproduction technique: egg laying. The gestation of the platypus eggs last around 15-21 days and incubation from 6-10 days making offspring comparable in size to marsupials (Warren et al., 2008). Egg laying strictly lies with groups such as reptiles and birds. Although the platypus lays eggs, it still participates in a form of lactation which is the most important time for infant growth like marsupials. One difference between marsupial and platypus lactation arises from the platypus’ lack of a nipple. Although, the milk of the platypus contains all the essential nutrients and anti-microbial agents enriching and protecting the young much like mammals (Warren et al., 2008). This is yet another fact eliciting the importance of the platypus in evolutionary history. It blends both forms of reproduction and lactation utilizing both as a process of survival. Although egg laying is quite unique to monotremes; it does not seem to be the most alarming and unique feature similar to birds and reptiles. A unique characteristic of the platypus does not just occur with egg laying but also with its ability to be venomous. Although being venomous is not exclusive to one mammal (namely the shrew), the platypus harnesses and releases this venom through a hollow bone spur behind each hind leg. They produce venom defensing-like peptides (OvDLP) which are beta-defensins that are similar to snakes and reptile crotamine-like peptides (Whittington et. al., 2008). Previously, this venom was thought to catch prey and defend against predators; however, it is now theorized as a mating technique. The bone spur is sex specific to males, and the platypus only creates this venom during breeding season. Due to season specific venom production, a new theory is well supported as a fighting technique. This venom is powerful enough to bring a human down and put him in extreme pain which is resistant to first aid methods and drugs such as morphine (Whittington et. al., 2008). Since venom production occurs during breeding season, males compete and convey dominance representing a type of intersexual selection. This type of sexual selection gives rise to female choice and depicts females as the limiting resource in the environment. Venom production is most pronounced in reptiles, yet the platypus developed this ability and uses it mostly as a mating technique enhancing its reproductive success. Through evolution, its importance has become crucial in understanding the transition from reptiles to mammals; however, how has this mammal been able to succeed? One form of survival is its ability to hunt food. The platypus’ large bill does not serve just as a mouth but as a large electroreceptor for discovering food on the river bottom. Being able to detect electric disturbances has led to increased likelihood of catching prey. This method of hunting correlates to a hammerhead shark or dolphin finding prey. It has been studied that while swimming the animal “swings its head backwards and forwards in roughly sinusoidal fashion” in order to detect food (Pettigrew 1999). Not only that, the bill and brain are in sync allowing the platypus to detect mechanical disturbances of the prey. By using a combination of electroreception and mechanoreception, the platypus becomes a very successful hunter of worms and freshwater shrimp. The monotremes and platypus have been seen as a primitive species but this feature of electroreception and mechanoreception evolution indicates an opposite conclusion. The platypus is highly modified but its own evolution does not stop there. The platypus has developed a unique type of gastric function different from all other mammals. So unique, in fact, there have been a loss of genes in the gastric functions of the platypus which enhances its survival. The platypus genome has lost the pepsin gene. What does this exactly mean? This gene deals with the pH acidity in almost all mammals, which differentiates the platypus from other mammals. The pepsin gene allows gastrin to decrease pH (increase acidity) within the stomach when it becomes noticeably low but what does this mean for the platypus? Through this loss, the platypus has a higher pH in its stomach for digestion. How does this benefit the platypus? It has been theorized that many parasites and pathogens are unable to survive in a higher pH (more basic) stomach providing a selective advantage toward the loss of the pepsin gene (Ordoñez et al., 2008). This conveys a distinction between all other mammals and the platypus in general. Not only does the high pH help its survival, the platypus has an unnatural immunity. Its genome contains “at least 214 natural killer receptor genes within the natural killer complex […] much larger than for humans (15)” (Warren 2008). The platypus has developed selective features and evolved new methods of survival which might help explain its continuous existence. Its ability to prevent pathogen growth within its stomach, and its high natural immunity convey a more evolved species than we realize. The platypus is a strange looking creature with webbed feet, a beaver’s tail, and a flat bill. By harnessing qualities and characteristics of both mammals and reptilians, the platypus is a crucial creature in understanding the development of mammals from reptilians. The platypus uses qualities from both groups conveying its adaptability and evolution of the mammalian group. It has similar sexual determination as birds, lays eggs like a bird and reptile, has venom, but has hair like a mammal. Feeding its young much like a mammal through lactation, it provides the nutrients and immunity to survive. This creature has evolved a mechanical ability of electroception to effectively hunt its prey on the river floor. Lastly, it has developed and deviated from almost all mammals through its loss of the pepsin gene. This creature is truly phenomenal, beautiful, and crucial in the understanding the evolution of mammals. Through its survival, it is easily noted that this mammal is selectively fit for its environment and a living fossil today.





References Ordoñez, Gonzalo, et al. “Loss of gene implicated in gastric function during platypus evolution.” Genome Biology 9: (15 May 2008): 1-11. Web. 14 September 2014. <genomebiology.com/2998/9/4/R81> Pettigrew, John. “Electroreception in Monotremes.” The Journal of Experimental Biology 202 (April 1999): 1447-1454. Web 28 September 2014. <http://jeb.biologists.org/content/202/10/1447.full.pdf> Veyrunes, Frédéric, et al. “Bird-like sex chromosomes of platypus imply recent origin of a mammal sex chromosomes.” Genome Research 18 (7 May 2008): 965-973. Web. 13 September 2014. <doi:10.1101/gr.7101908> Rens, Willem. “Epigenetic modifications on X chromosomes in marsupial and monotreme mammals and implications for evolution of dosage compensation.” PNAS 2010 107 (September 2010) 17657-17662. Web. 29 September 2014. <doi:10.1073/pnas.0910322107> Rosalind, John. “Genomic Imprinting, Mammalian Evolution, and the Mystery of Egg-laying Mammals.” Cell 101 (June 2000): 585-588. Web. 28 September 2014. <https://www.uam.es/personal_pdi/ciencias/genhum/biblioparte2/origenimprinting.pdf> Retief, Jacques, et al. “Evolution of the Monotremes.” Department of Medical Biochemistry 218 (7 September 1993): 457-461. Web. 14 September 2014. <http://onlinelibrary.wiley.com/doi/10.1111/j.1432-1033.1993.tb18396.x/pdf> Warren, Wesley, et al. “Genome Analysis of the platypus reveals unique signatures of evolution.” Nature 453 (8 May 2008): 175-183. Web. 14 September 2014. <doi:10.1038/nature06936> Whittington, Camilla, et al. ”Defensins and the convergent evolution of platypus and reptile venom genes.” Genome Research 18 (7 May 2008): 986-994. Web. 14 September 2014. <doi:10.1101/gr.7149808> Flint.39 (talk) 20:05, 14 November 2014 (UTC)Dillon Flint[reply]

Hi there, I'm HasteurBot. I just wanted to let you know that Draft:Platypus evolution and ancestry, a page you created, has not been edited in 6 months. The Articles for Creation space is not an indefinite storage location for content that is not appropriate for articlespace.

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