CONNECTIONS TO OTHER PHYLA

Echinodermata is a very unique phyla in that its organisms live in marine habitats only. Organisms belonging to crustecea, a subphylum of arthropoda, also live in water only, but can be found in fresh water as well as salt water. Other phylums that are strictly aquatic are cnidaria and porifera, but once again these organisms can be found in fresh water and marine habitats. However the phyla with the most similar habitat characertistics is mollusca.
Organisms of the phyla echinodermata all have penta radial symetry, similarly to this cnidarians have radial symetry. Another characteristic they hold is thier endoskeleton, certain members of phyla mollusca also share this characteristic, such as the squid.
A similar function between annelids and echinoderms is that they both have specialized segments of the body. Echinoderms all have an intersection like center, where a majority of their internal organs are found. Annelids too have a specialized first few segments that carry their eyes or antennae. Both starfishes and sea stars from echinodermata have a similar function to octopus's from the phyla mollusca. Both these organisms have suction like appendages, though they are not controlled by the same kind of system their suction like charactaristics make them comparable.