Regeneration is a process in which tissue molds itself into an exact replica of an injured or severed part. The process of regeneration depends on different factors such as the environment and the development of the organism in question (Br, 1955). Regeneration occurs in several steps and the organism must have the ability to perform each one for successful regeneration with minimal loss of necessary function. First, after a wound is made muscular contraction closes up the wound (Pellettieri et al., 2010). Next a blastema, a group of undifferentiated cells, forms and will differentiate into the missing parts. Lastly the undifferentiated cells go through epimorphosis where the lost parts are formed by the blastema (Reddien & Sánchez Alvarado, 2004).
One organism well suited for regeneration is Dugesia dorotocephala, more commonly known as black planaria. Planarians are flatworms classified under the phylum Platyhelminthes and are bilaterally symmetrical. They are usually found in freshwater streams and ponds (Br, 1955). Planarians are unique in which they can reproduce both asexually and sexually. Planarians can reproduce asexually through transverse fission. Planarians are also hermaphrodites in which they can reproduce through cross fertilization. Planarians prefer to reproduce through fission where the organism splits in two and regenerates itself (Curtis & Schulze, 1933).
Past experiments using Dugesia dorotocephala, show the ability of planaria to regenerate after severing the organism into different parts (Sánchez Alvarado, 2006). Planaria with transversal cuts below the head and above the tail will produce regenerated segments due to the planaria’s ability to form Neoblasts and undergo epimorphosis to create new body segments from existing tissue and stem cells.
Material and Methods
Eight black planarians from the species Dugesia dorotocephala were severed using a transversal cut. The eight planarians were split into two groups as two different cuts were performed. The first cut right below the head, yielded eight replicates and produced short heads and long bodied segments. The second cut right above the tail, yielded eight replicates as well and produced long heads and short bodied segments.
The pieces were placed into petri dishes containing spring water and properly labeled with the type of segment produced by the cut. The dishes were placed in a dark cabinet at room temperature and left undisturbed. After one week, the planarians were observed for partial or full regeneration or death of the organism. Data was collected and recorded. The water was replaced with new spring water and the planarians were returned to the cabinet. After the second week, the observations were repeated and the data was recorded.
After one week, the planarians were observed for partial regeneration, full regeneration, or death. Planarian segments of long heads fully regenerated within the first week. One long tail segment died and all the...