Phylogeny
The planarians, like Dugesia, are one of the types of non-parasitic flatworms that have been an object of numerous investigations and studies due to their phylogeny, anatomy, ecology, and even regeneration peculiarities (Ruppert, Fox, Barnes, 2004). About 70 species of Dugesia are already known (aenigma, japonica, notogaea, etc.), and its phylogeny is identified due to its diagnostic characters but not due to its apomorphies which are usually used in the analysis of other types of worms and planarians (Lazaro, Sluys, Pala, Stocchino, Baguna, Riutort, 2009). Classification of Dugesia is as follows (Lal, 2009): Phylum: Platyhelminthes; Class: Turbellaria; Order: Tricladida; Suborder: Paludieola; Family: Planariidae. There are many reasons of why Dugesia may be set apart from other members of the similar group, and one of the most common issues is that this planarian makes individuals feel a trophic benefit from this group due to asexual populations, which are increased to a considerable size without loss or even replacement of individuals (Lewbart, 2011).
Anatomy
With the help of numerous investigations, Dugesia structure and functions becomes more or less clear (Natsuka, Hirohata, Nakakita, Sumiyoshi, Has, 2011). This worm may be of black, brown, or grey colors depending on its species. As a rule, it has a triangle-shaped head with a couple of eyes that help them to control the water current intensity. It is also characterized by a unique system of neuroscience and neurogeneration that makes them rather simple still useful for understanding (Nishimura, Kitamura, Taniguchi, Agata, 2010).
Ecology
From the ecological point of view, Dugesia does not have too many specifics. It may be found in freshwater ponds, streams, and lakes of such countries like India, Russia, United Kingdom, the United States of America, and Myanmar (Kotpal, 2012; Pongratz, Storhas, Carranza, Michiels, 2003).
Regeneration
The regeneration process in Dugesia has its rules as any regeneration of planarians. Still, it differs from other forms of worms due to its hermaphroditic nature and the possibility to reproduce asexually and sexually at the same time. However, asexual multiplication is rather rare in the animal kingdom (Reuter, Kreshchenko, 2004), and the regeneration of Dugesia stem cells as well as pharynx and head has its particular role in the development of the chosen class. Finally, the regeneration process of Dugesia gives rise to a number of missing cell types (Umesono, Tasaki, Nishimura, Inoue, Agata, 2011).
Objectives and Hypothesis
The analysis of neuroscience and neurogeneration of Dugesia helps to comprehend the role of the chosen group of worms and their possible effects. The main objective of current research is to introduce Dugesia as a useful organism with its own place in the natural world. Various Dugesia species have their own peculiarities, still, their common regeneration process with the cellular and molecular dissection may considerably improve the understanding of the dynamics of the regeneration process that takes place in the brain, stem cells, and pharynx.
Methods
First, the evaluation of literary sources and previous investigations on Dugesia, its features, and regeneration process is made to understand a true essence of the chosen type of worms. Second, the experiment on Dugesia asexual multiplication has been made. Finally, the analysis of Dugesia structure was done in the laboratory conditions in order to identify the conditions under which Dugesia worm may be referred to a hermaphrodite type (the asexual reproduction of the pharynx and the sexual reproduction of the brain and stem cells).
Works Cited
Kotpal, R.L. 2012. Modern Text Book of Zoology: Invertebrates. Rastogi Publications, New Delhi, India.
Lal, S.S. 2009. Practical Zoology: Vol, 3. Rastogi Publications, New Delhi, India.
Lazaro, E.M., Sluys, R., Pala, M., Stocchino, G.A., Baguna, J., Riutort, M. 2009. Molecular barcoding and phylogeography of sexual and asexual freshwater planarians of the genus Dugesia in the Western Mediterranean (Platyhelminthes, Tricladida, Dugesiidae). Molecular Phylogenetics and Ecolution 52 pp.835-845.
Lewbart, G.A. 2011. Invertebrate Medicine. John Wiley & Sons, West Sussex, UK.
Natsuka, S., Hirohata, Y., Nakakita, S., Sumiyoshi, W., Has, S. 2011. Structural analysis of N-glycans of the planarian Dugesia japonica. The FEBS Journal 278(3) pp. 452-460.
Nishimura, K., Kitamura, Y., Taniguchi, T., Agata, K. 2010. Analysis of motor function modulated by cholinergic neurons in planarian Dugesia Japonica. Neuroscience 168 pp.18-30.
Pongratz, N., Storhas, M., Carranza, S., Michiels, N.K. 2003. Phylogeography of competing sexual and parthenogenetic forms of a freshwater flatworm: patterns and explanations. BMC Evolutionary Biology 3(23) pp. 323-15.
Reuter, M., Kreshchenko, N. 2004. Flatworm asexual multiplication implicates stem cells and regeneration. Canadian Journal of Zoology 82(2) pp. 334-356.
Ruppert, E.E., Fox, R.S., Barnes, R.B. 2004. Invertebrate Zoology: A Functional Evolutionary Approach. Brooks Cole/Thomson, Belmont, CA.
Umesono, Y., Tasaki, J., Nishimura, K., Inoue, T., Agata, K. 2011. Regeneration in an evolutionary primitive brain – the planarian Dugesia japonica model. Eropean Journal of Neuroscience 34 pp. 863-869.