Echinoderm Form, Function and Locomotion Flashcards
What does echinoderm mean?
Spiney skin
What are the 5 main living classes?
Asteroidea
Ophiuroidea
Echinoidea
Holothuroidea
Crinoidea
What are the common features of echinoderms?
- No head or brain
- Deuterostomes (blastophore forms anus then mouth)
- Specialised gills for oxygen transport/gas exchange
- Coelomate
Are echinoderms deuterostomes or protostomes?
Deuterostomes
Where are echinoderms found?
Marine - found from intertidal to deep waters. Mainly benthic living.
How many coelomic systems do echinoderms have?
4
What are the 4 coelomic systems of echinoderms?
- Perivisceral coelom - guts and gonads
- Haemal system - nutrient distribution?
- Peri-haemal system - nutrient distribution?
- Water vascular system (WVS)
What is the endoskeleton of echinoderms made up of?
Small calcareous plates called ossicles, bound together by catch collagen
What kind of symmetry do adult echinoderms show?
Radial pentamerous symmetry
How many arms do asteroidea usually have?
Usually 5 but can be over 40 (e.g. sunstars)
What animals are within Asteroidea?
Starfish or sea stars, sea daisies
What animals are within Ophiuroidea?
Brittle stars
What animals are within Echinoidea?
Sea urchins, sea biscuits, sand dollars
What animals are within Holothuroidea?
Sea cucumbers
What animals are within Crinoidea?
Sea lillies and feather stars
Where is the mouth of Asteroidea (starfish) located?
Underside
What is the name of the groove that runs down the arms of Asteroidea (starfish) and what is this surrounded by?
Ambilacral groove which is surrounded by tube feet (podia)
What do Asteroidea (starfish) have on the ends of their arms?
Sensory tentacles and eyespots
What do Asteroidea (starfish) have on their aboral surface?
Spines and pedicellariae
What are the respiratory structures of Asteroidea (starfish)?
Projections of coelomic cavity (Papulae) which bring oxygen to the peri-visceral coelom. Tube feet can also act as gills for oxygen transfer to the water vascular system (WVS) which opens to outside via madreporite
Where are Ophiuroidea (brittle stars) found?
Benthic, range of depths
How many arms do Ophiuroidea (brittle stars) generally have?
5
What do Ophiuroidea (brittle stars) lack, which Asteroidea (starfish) have?
Ambulacral grooves, papulae and pedicellariae