echinoderm
Radially symmetric invertebrate
An echinoderm is a marine invertebrate with radial symmetry and a spiny skin—starfish, sea urchins, sand dollars, and sea cucumbers.
The name means "hedgehog skin" in Greek.
All echinoderms have a water-based vascular system that powers their tube feet for movement and feeding.
They lack a brain but have a decentralized nervous system.
Five-armed marine invertebrate
- AsteroideaMarine star-shaped class
- asteroidSun-orbiting rocky mass
Invariance under transformation
- ossiclesMinute skeletal structures
- testEvaluative examination
- coelomMesoderm-lined internal space
- dermalOf the skin
calcite · regeneration · bilateral · larvae
Eats dead organic material
- benthicOf the sea bottom
- sessileAttached at base
- regenerationBiological self-repair process
- filter-feederOrganism extracting food from water
grazer · scavenger · oviparous · metamorphosis · evisceration
Massive saltwater body
- seafloorOcean's solid base
- tidepoolCoastal rock hollow holding seawater
- coral-reefSubmarine calcium carbonate ecosystem
- abyssalExtremely deep, unmeasurable
saltwater · currents · intertidal · subtidal · pelagic · estuary · seagrass
Column of vertebrae
- testEvaluative examination
- spikeSharp rise or point
- pointedTapering to a tip
- sharpFine-edged, or astute
protective · venomous · needle-like · crown-of-thorns · barbed
Earliest Paleozoic period
- fossilPreserved ancient organism
- OrdovicianPaleozoic geological period
- blastoidExtinct stalked echinoderm
- PaleozoicEarly complex-life epoch
extinction · limestone · calcified · prehistoric · evolution · ancestral
starfish
Five-armed marine invertebrate
- AsteroideaMarine star-shaped class
- asteroidSun-orbiting rocky mass
symmetry
Invariance under transformation
dermal · calcite · regeneration · bilateral · larvae
detritivore
Eats dead organic material
- benthicOf the sea bottom
- sessileAttached at base
- regenerationBiological self-repair process
filter-feeder · grazer · scavenger · oviparous · metamorphosis · evisceration
ocean
Massive saltwater body
- seafloorOcean's solid base
- tidepoolCoastal rock hollow holding seawater
- coral-reefSubmarine calcium carbonate ecosystem
abyssal · saltwater · currents · intertidal · subtidal · pelagic · estuary · seagrass
spine
Column of vertebrae
sharp · protective · venomous · needle-like · crown-of-thorns · barbed
Cambrian
Earliest Paleozoic period
- fossilPreserved ancient organism
- OrdovicianPaleozoic geological period
- blastoidExtinct stalked echinoderm
Paleozoic · extinction · limestone · calcified · prehistoric · evolution · ancestral
- life formsorganisms, organism, lifeforms, animal, creatures
- ocean lifeocean, sea, sea creatures, shark, sea life
- zoologymammals, reptiles, amphibians, birds, insects
- eukaryotesanimals, animal, nucleus, fungi, plants
- echinodermssea urchin, sea star, sea cucumber, brittle star, sand dollar
- radial thingsspoke, radial tires, wheel, hub, rim