Chapter 22: Chaetognaths, Echinoderms, Hemichordates

echinoderm trait

deuterstome

chaetognaths trait

mixed

evolved from bilateral ancestors but are radial as adults

echinoderms

coelom is modified into a ____ for movement

water vascular system

phylum chaetognatha common name

arrow worms

phylum chaetognatha roots

chaite (long, flower hair) and gnathos (jaw)

phylum chaetognatha description

marine, planktonic predators

phylum chaetognatha behavior

swim to surface at night, descend during the day

phylum chaetognatha movement

drift but can swim in short bursts

phylum chaetognatha unsegmented body

head, trunk, post anal tail

phylum chaetognatha ____ leads to mouth

vestibule

phylum chaetognatha vestible

deoression beneath head

phylum chaetognatha mouth contains

teeth and chitinous spines

phylum chaetognatha eyes

dorsal

phylum chaetognatha hood

covers eyes and vestibule

the only invertebrates with a multi layered epidermis

phylum chaetognatha

high mobile and transparent

phylum chaetognatha

phylum chaetognatha lack

respiratory and excretory system

phylum chaetognatha mechanoreceptive/chemosensory

u shaped ciliary loop

phylum chaetognatha reproduction

hermaphroditic with self or cross fertilization

phylum chaetognatha are likely

deuterstomes

phylum echinodermata unique feature

water vascular system

phylum echinodermata adult symmetry

pentaradial

phylum echinodermata larva symmetry

bilateral

phylum echinodermata endoskeleton made of

dermal, calcerous ossicles

phylum echinodermata nervous system

no brain but extensive nerve ring

regeneration prominent

phylum echinodermata

phylum echinodermata reproduction

asexual by fragmentation

phylum echinodermata lack

excretory organs

phylum echinodermata circulation by

peritoneal cilia

phylum echinodermata fossil record dates to

cambrian

phylum echinodermata evolved radial symmetry due to

sessile lifestyle

cannot osmoregulate

phylum echinodermata

important for evolution and developmental biology

phylum echinodermata

class asteroidea common name

sea stars

class asteroidea life style

predatory

class asteroidea body

central disc with tapering arms

class asteroidea covered with a

ciliated, pigmented epidermis

class asteroidea oral side

mouth and ambulacral groove with tube feet

class asteroidea aboral side

spines, pedicellariae, papulae (gills)

class asteroidea madreporite

connects to water vascular system

class asteroidea endoskeleton

ossicles bound with catch collegen (change from liquid to solid)

class asteroidea stereom

mesh in ossicles

class asteroidea water vascular system function

locomotion and food gathering

class asteroidea water vascular system flow

madreporite > stone canal > ring canal > radial canal > lateral canal > tube feet with ampullae

class asteroidea digestive system flow

mouth > esophagus > large stomach (everted)

class asteroidea ___ in arms

pyloric ceca

short intestine, no anus

class asteroidea

class asteroidea prey

molluscs, echinoderms, bivavles

class asteroidea oral/ectoneural system

nerve ring around mouth, radial nerves in arm

class asteroidea deep/hyponeural system

ring around anus, radial nerves in roof of each ray

class asteroidea nerve plexus/nerve net

connects the two system

class asteroidea ___ at arm tips

ocellus

class asteroidea larva stages

bipinnaria > brachiolaria

class asteroidea regenerates lost parts by

central disc

sea daises shape

disc

sea daises symmetry

pentaradial but no arms

class ophiuroidea common name

brittle stars

class ophiuroidea arms

slender, lack pedicellariae/papulae

class ophiuroidea movement via

muscle contractions; no suckers on tube feet

class ophiuroidea madreporite

on oral surface

class ophiuroidea digestion

sac like stomach; no anus/intestine

class ophiuroidea arm

column of ossicles

class ophiuroidea jaw

five moveable plates

class ophiuroidea five bursae

pockets for gas exchange and gametes

class ophiuroidea larva

ophiopluteus

class ophiuroidea behavior

nocturnal, light sensitive

class echinoidea common name

sea urchins, sand dollars

class echinoidea body

compact

class echinoidea endoskeleton called

test

class echinoidea symmetry

hemispherical and radially

class echinoidea locomotion

tube feet

sand dollar symmetry

secondarily bilateral

sand dollar spines

smaller for movement

class echinoidea test consist of

10 double row of plates; 5 rows of ambulacral rows

class echinoidea moveable spines via

basal muscles

class echinoidea pedicellariae

three jawed, stalked, some venomous

class echinoidea specialized digestive structure

aristole’s lantern (rasping teeth)

class echinoidea ___ connects esophagus to intestine

ciliated siphon

class echinoidea gas exchange via

water vascular system

class echinoidea petaloids

respiratory feet

class echinoidea hemal and nervous system similar to

asteroids

class echinoidea larva form

echinopluteus

class holothuroidea common name

sea cucumbers and sea pigs

class holothuroidea body

leathery with tiny ossicles in skin

class holothuroidea tube feet only on

sole side

class holothuroidea colaca

shared with digestive and respiratory tree

class holothuroidea larva form

auricularia

class crinoidea common name

sea lilies and feather stars

class crinoidea body

calyx with five flexible arms and pinnules; forms crown

class crinoidea calyx

body disc with tegmen and calcerous plates

class crinoidea feeding

open, ciliated ambulacral grooves

class crinoidea oral surface digestive system flow

mouth > esophagus > intestine (diverticula) > anus (raised cone)

class crinoidea water vascular system uses

coelomic fluid

class crinoidea structures in arms

oral nerve ring, radial nerves, gonands

class crinoidea larva

doliolarium

phylum hemichordata roots

hemi (half) and chordata (string or chord)

phylum hemichordata support structure

buccal diverticulum (stomochord)

phylum hemichordata habitat

secreted tubes in marine sediments

class enteropneusta common name

acorn worms