PISASTER THE NEXT LARVAL REGENERATION

Abstract

Sea stars are common invertebrates that inhabit all oceans. These organisms belong to the phylum Echinodermata, which include sea cucumbers, sand dollars and sea urchins. The sea star Pisaster ocharaceus is native to the Pacific Ocean, stretching from Northern Alaska to Northern California. They appear in different color morphs, ranging from purple to orange and even brown. Like other sea stars they have tube feet, which give them the ability to move and secure themselves on any surface, making it difficult for predators, including humans to obtain it. They normally thrive on common bivalves such as muscles, but also consume barnacles and chitons, however during their larval stage they mostly feed on algae. Using their tube feet they can latch on to different prey and bring them to their mouth to feast. Pisaster ochraceus is known to have its mating Pisaster sea stars have separate sexes, which can be determined by making a slight incision at the base of the arm and locating the gonads, which will contain either sperm or eggs. . Many sea stars have the capacity to regenerate body parts lost during their lifetime, but only in their adult stages. However, I am more interested in learning about this mechanism during their larval stage. Not only does regeneration affect different organs in the specimen, but also different cells (Carnevali 2006). This paper will show the processes of obtaining the specimens, bisecting the larval sea stars, and finally displaying them in different colors, allowing viewers to not only see the common organs such as the mouth, anus, esophagus and stomach, but also different muscle tissues. In this study, we investigate the regenerative abilities of 200 larvae bisected in various morphological planes and fixed over a series of time points to observe the progress of each bisected culture.