GENERAL HISTOLOGY

Detailed explanation-1: -Today, Echinodermata is a diverse phylum, with numerous species in five classes: Asteroidea (star fish), Crinoidea (sea lilies and feather stars), Echinoidea (sea urchins and sand dollars), Holothuroidea (sea cucumbers), and Ophiuroidea (brittle stars).

Detailed explanation-2: -Examples of echinoderms include sea stars, sea urchins, sea cucumbers, brittle stars, and feather stars (Fig. 3.83). Although they may appear very different, echinoderms all have two major defining characteristics that set them apart from all other animals: a water vascular system and five-sided radial symmetry.

Detailed explanation-3: -One characteristic of an echinoderm is that they all have pentamerous radial symmetry. This simply means they all have 5 equal body parts. You can divide these animals into five equal parts, and every part is the same. For example, most sea stars have five arms or a multiple of five arms.

Detailed explanation-4: -Even sea cucumbers, which show a more worm-like appearance, usually exhibit this body plan, known as pentameral symmetry. Most species have an arm number that is an increment of five-there are even echinoderms that display great numbers of arms, with some sea stars having up to 50.

Detailed explanation-5: -They have a star-like appearance and are spherical or elongated. They are exclusively marine animals. The organisms are spiny-skinned. They exhibit organ system level of organization. They are triploblastic and have a coelomic cavity. The skeleton is made up of calcium carbonate. More items