Echinoderms (General) Flashcards
adaptive zone
all marine
many feeding types
no parasites
dominate sea floors
economically important roles
fisheries
pests
important developmental features
- cleavage
- stome
- photoreceptors
radial cleavage
deuterostomes
ciliary photoreceptors
nerve chord for
- protostomes
- deuterostomes
- ventral
- dorsal
Classes
Asteroidea- starfish
Ophiuroidea- brittle stars, *basket stars
Holothuroidea- sea cucumbers
Echiniodea- sea urchins and sand dollars
Criniodea- sea lillies, *feather stars
*Concentricycloidea- sea daisies (may be part of Asteroidea)
Defining features (8)
- pentaradial body plan
- no cephalization
- water vascular system
- mutable connective tissue
- endoskeleton
- pedicellaria
- spacious coelum
- no excretory system
water vascular system
- fluid filled channels connected to external surface through madreporite
- derived from coelum
- used for locomotion, respiration and sensory
ambulacral grooves
where tube feet come out
tube feet
hydraulically extended appendages (sometimes w/ suckers)
-ampullae- like perfume bottle squeezers used to extend tube feet
mutable connective tissue (catch collagen)
- cool shit
- can go from hard to soft and back again… ;)
- neurosecretory control
- saves enegry (no muscle contraction required)
endoskeleton
- plates or ossicles
- porous
pedicellaria
- prevents bio-fouling/cleans
- defensive
- some venomous
arrangement of nervous system
radial
