What Is Planaria Regeneration In Ideal Temperatures

Planaria Regeneration in Ideal Temperatures vs. Cold Temperatures

Christina Malfas

Abstract Planaria are flatworms that live in quiet freshwater bodies. They live in a narrow range of temperatures, from 22-24°C. They regenerate asexually, specifically through a process called epimorphosis, in which they completely regenerate one half of their bodies after splitting themselves in two. The diffusion gradient model assumes that cells in an organism “know” their orientation on that organism due to concentration of morphogen surrounding them. The morphogen is most abundant at one end of the planaria, and diffuses down the length of it. In this lab, their regenerative capabilities will be experimented with. Since planaria live in such a narrow range of temperatures, their morphogen concentration gradients could be dependent on these specific conditions. If placed under colder temperature conditions, then the planaria will not regenerate correctly, because their morphogen concentration gradients will have been thrown off by the change in conditions. While at the end of the experiment, many of the planaria in the experimental did appear to be growing incorrectly, the results cannot be conclusive. The colder temperature also caused growth rate to be greatly inhibited, so the
The diffusion gradient model explains this phenomenon. It proposes that cells know their orientation on an animal by concentration of a chemical substance, called a morphogen in this case, surrounding them. The morphogen concentration forms a “gradient” down the organism, being most concentrated at one end and diffusing out down the length of the organism. When the blastema in epimorphosis forms, the cells that will redifferentiate into the new half of the organism sense the morphogen concentration in the area they are in, and thus know what half they are going to form (Vervoort