The Echindermata Flashcards
What was the time period of the Echindermata?
Cambrian to recent
What does deuterostoma mean?
The anus is developed before the mouth.
Where do they primarly live?
They’re benthic - live on the sea floor.
What are their skeletons composed of?
Their skeletons are composed of monocrystalline porous calcite plates.
Where’s does their skeleton’s lie within their bodies?
It’s mesodermic - their skeleton’s lie underneath a thin layer of skin.
Explain what the water vascular system is?
Water enters though the stone canal and this water fills up the muscle allowing it to contract/expand using hydrostatic pressure.
Croinoids and star fish have what type of symmetry?
They have pentameral - five fold symmetry.
What time period did croinoids live in?
Cambrian to recent
Croinoids feed on what?
They’re filter feeding organisms which use their branchials to filter food - also they use these to move.
Which marine environment did croinoids used to live in?
They used to live in open seas.
What is the Latin name for sea urchins?
Eleuthrozoans
What timescale did Eleuthrozoans live in?
Ordovician - recent
What type of symmetry do regular Echinoids have?
They have pentameral symmetry
Explain their body structure - regular Echinoid.
They have a periproct in the centre of their body, 5 different interambulacral areas and 5 different ambulacral areas. Covering all of these area are podia.
What’s the ambulacral system?
This is the water vascular system in Echinoidea.
