Echinodermata (Starfish/Sea Urchins)

Family: Echinodermata
This class consists of starfish and sea urchins. These organisms have plates covered with spines.

Asteroidea
This class consists of true starfishes. These starfishes can regenerate loss parts, which are thick arms. Brittle stars are classified into another group since they have arms that can move and slither faster.

​Ophiuroideas
This class consists of brittle stars. Since you're probably wandering why this isn't part of Asteroidea, it's because they have flexible arms used for locomotion. Unlike their cousins, true sea stars often crawl slower, and mostly use their arms to edge themselves into cracks or their prey.

​Holothuroidea
This class consists of sea cucumbers. Sea cucumbers have leathery skin and an elongated (long) body. Most are covered in spikes, while others are either bumpy or smooth. A sea cucumber's diet is comprise of mostly algae.

​Ehinoidea
This class is comprise of sea urchins. They move slowly, munching on algae or kelp. Their main predators that hunt them are otters, starfish, wolf eels, triggerfish, and other predators hunt and feed on sea urchins. Inside of a sea urchin lies a juicy middle that often tastes like fish. Their roe (inside) is a famous delicacy in many foreign restaurants.

​Crinoidea
This group are a diverse taxonomy of sea lilies. They live in both shallow water and in depths as great as 9,000 meters. Because of their feathery arms that sway in the currents, they are given the name sea lilies. To capture food, microorganisms or microscopic plants float through its feathery arms.