These are named after a class of Earth creatures that include starfish and sea cucumbers (though are unrelated to them genetically). They are complex organisms at least centimetres in size. They include all types of aquatic, normally invertebrate, creatures that crawl on the sea bed. They are a type of animal life that tends to evolve early on in a planet's evolution, but can last for hundreds of millions of years.
The level of the resource has some effect on the type of Echinoderms present on the world. Note that these aren't strict limits, and can overlap.
|1 - 30||Small creatures, mostly centimetres in size and mostly grazers.|
|31 - 60||Medium sized creatures, tens of centimetres in size and can be predators.|
|61 - 90||Large creatures, can be metres in size and often predatory.|
|91 - 120||Dominant aquatic life form, roaming the seabed in packs and hunting other creatures.|
|121+||This kind of life is unusually sized and dominant, probably also swimmers.|
Can these evolve to move onto land? Probably yes, in which case are they the same resource type, or a different resource type?