The Asteroidea class, also known as the sea stars, has many common characteristics. Firstly, all sea stars have flat, star-shaped bodies as well as a central disc with radiating arms/rays protruding out. Typically, seastars has five arms but certain species can have up to fifty arms! The size of the sea stars is not consistent through the different species therefore varies from one centimeter to three feet. The skeletal system is a key aspect for the survival of a sea stars. Sea stars have bilateral symmetry. The skeleton is made up of ossicles which helps make for flexibility yet firm enough to hold together. Their flexibility enables them to catch prey easily and sufficiently. The spine and pedicellariae is small and movable. On the upper …show more content…
They are found in almost every marine habitat whether it be in tidal pools or in the sea. They are usually found on the seafloor which is why the suckers are very important. They can stick to the ground and move along it easily. They also can adhere firmly to their prey and capture them. Their sensors help them stay alert for prey or predators. Their suctions help them survive extreme changes in environment like crashing waves or tidal waves. Their digestive system allows them to eat many different types of prey or smaller animals. The ambulacral grooves help to open shells enabling sea stars to digest …show more content…
Anjali- (genus) Asterias: They can be found near North America on either coast, usually on rocky sea bottoms. There amount of arms vary from five to forty and the size of the sea star usually ranges from ten to twenty centimeters. The lower surface is flatter than the aboral surface. The ossicles has an irregular arrangement and the mouth is in the center of the oral surface. It has a very unique water vascular system which has a ring around its mouth.
Anjali- (species) Asterias forbesi: Asterias forbesi usually have five arms which are around six centimeters. Their sizes ranges around fifteen centimeters. Majority sexually reproduce by producing larvae.They can sense their prey through chemoreception. They are mainly found on the east coast of North America. There are many rows of tube feet and the grooves run down the center of each arm on the oral surface. Their madreporite, usually pink, is their filter for water.
Sasha - (genus) Choriaster: The genus, Choriaster, only has one species, so all of it’s characteristics are the same as it’s one