15. Echinodermata Flashcards
what are Echinoderms? also give four the steps (pronouced, Eh-Kiee-No-Derm)
they are deterostomes which means they have
straight clevage which is radial
the folds of archentron form the coelom
anus forms from blastopore
fate of blastopore is later in development
name three phylums that are deuterosomes and four phylums that are protosomes
deuterosomes: echinoderms, hemichordates, chordates
protosomes: flatworms, annelids, arthropods, molluscs
what type of specie is an echinoderm?
starfish sea stars and sea urchins!!
what are four charateristics of echinodermata?
they are marine
slow moving or sessile
diocious (male and female seperate)
have an endoskeleton with ossicles covering it (a thin skin which covers the endoskeleton plates)
what is special about echinodermatas skeleton?
its endoskeleton derives from mesoderm made of calcium carbonate which are called ossicles
what do the tube feet in echinodermata do? 5 points
locomotion
feeding
sensory
gas exchange
protection
what is the water vascular system in echinodermata?
a network of hydraulic canals branching from the central disk ring canal and go into the limbs called the tube feet
what is the madreporite?
the site where water flows in to power the water vascular system
what are ossicles? what are two benefits
Ossicles are small calcareous (calcium carbonate) elements on the dermis of the body wall of echinoderms. They form part of the endoskeleton.
provide rigidity and protection.
what is the ring canal central disk?
the equivelent of a brain, has a nerve ring and nerve cord radiating to the arms to control movement
what is the radial canal?
there are 5 radial canals which branch down the lenghth of every arm. water travels down the radial canal to fill up muscular tube feet with water for locomotion
what do the digestive glands do?
secrete digestive juices and aid in the absorbiton an storage of nutrtients
how do echinoderms reproduce?
sexual reproduction which involves gametes released into water by seperate male and female indiviudals (diosious)
what symmetry do echinoderms have? whats special about it?
have pentamerous radial symmetry. this is a secondary characteristic as juvenniles have bilateral symmertry
who is the internal transport by?
coelomic fluids
how is gas exchange and waste done?
occurs across tube feet and outersurface structures
what class are sea stars?
what are their major features
asteroidea (aster-roid-eea)
the dermis (skin) is protected by pedicllarice (tiny pincer)
dermal brachiae (skin gills) allow gas exchange
what class are sea urchins and sand dollars?
name 3 featuers
echinoide (eky-noiyy-de-a)
no arms
spherical body
skeltal ossicles are fused together to form flattened plates
what class are brittle stars?
name 3 features
ophiumroidea (off-rie-oid-ea)
arms are very mobile
suspension feeders, predators and scavengers
largest group of echinoderms
what class are sea lillies and feather stars?
what are three features
crinoidea (crin-oid-ea)
attached to a substrate by a stalk - are sessile (sea lillies)
oral surface directed upwards
feather stars have a stalk in development but not in adults
what class is a sea cucumber?
holothuroidea (hollow-thor-oid-ea)
what class are sea daisies?
three features
concentricyclodea (con-centric-cyclode-ea)
two species known
live on submerged wood
disk shaped
