6: Echinodermata and Hemichordata Flashcards
(20 cards)
- “mouth second”
- blastopore develops into anus
- all eucoelomate
Deuterostomes
clade within deuterostomia (echinodermata, hemichordata)
ambulacraria
deuterostome phylum:
- “spiny skin”
- radially symmetrical
- exclusively marine (most common in deep)
echinodermata
part of coelom is modified into a _____: seawater circulates around this system to facilitate gas exchange and hydrostatic pressure
water vascular system
_____ expand/contract w the pressure in the system
- each w muscular sac on inner and sucker on outer end
- facilitate gas exchange, nitrogenous waste
tube feet
the _____ on top of the body regulates the amount of water
madreporite
nutrients are circulated by a _______ _______ (reduced) and by _______ _______ (main circulatory structure)
hemal system; peritoneal cilia
echinoderms have true _____; made up of tiny “bones” called _______
endoskeleton; ossicles
- echinoderms have simple nervous system
- __________ with 5 nerves extending outward along the arms
- no structures similar to a brain
circumoral nerve ring
echinoderm 5 classes
- asteroidea
- ophiuroidea
- echinoidea
- crinoidea
- holothuroidea
echinoderm class:
- sea stars
- thick arms from central disk
- 5 arms where organs branch out into; eye spots on ends
- mostly carnivores
- 2 stomachs
asteroidea
echinoderm class:
- crown-of- thorns starfish
- feed on coral polyps
ancanthaster planci
acanthaster planci spines are covered in _____; cause liver damage
plancitoxins
echinoderm class:
- brittle stars
- largest group
- tube feet lack suckers
- similar to sea stars but long/thin/flexible arms
ophiuroidea
echinoderm class:
- sea urchins, sand dollars
- lack arms
- Flat or hemispherical w 5 rows of tube feet along
bottom
echinoidea
echinoderm class:
- sea cucumbers
- elongate w 5 rows of tube feet along bottom for movement
- ossicles reduced
- bilateral
- tube feet in mouth=tentacles for feeding
holothuroidea
echinoderm class:
- sea lilies, feather stars
- stalked suspension feeders
- Arms are branched and
lined with tube feet
crinoidea
deuterstome phylum:
- wormlike seafloor dwellers
- mostly sedentary
- coelomate
hemichordata
3 body parts of hemichordata
proboscis
collar
trunk
- active part of hemichordates
- Tonguelike structure
covered in mucus/cilia for collecting food
particles - used to burrow in some species
proboscis
