phylum echinodermata introduction. about 6000 species, all marine echinodermata

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Phylum Echinodermata Introduction

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Page 1: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

Phylum EchinodermataIntroduction

Page 2: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• About 6000 species, all marine

Echinodermata

Page 3: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• secondary pentamerous radial symmetryinternal skeleton

• water vascular system

Echinodermata Major characteristics

Page 4: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

Water Vascular System

• Madreporite

• stone canal

• ring canal

• radial canal

• lateral canals

• Ampulae

• tube feet

Page 5: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

CLASSIFICATION OF ECHINODERMATA

• Class Asteroidea

• Class Ophiuroidea

• Class Echinoidea

• Class Holothuroidea

• Class Crinoidea

Page 6: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

Class AsteroideaTrue Starfishes

Page 7: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

Class Asteroidea True Starfishes• arms not sharply

delineated from central disc

• tube feet with suckers; used for– Locomotion– obtaining food

• madreporite and anus aborally located

• some have pedicellariae - jawlike appendages of epidermis

Page 8: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• Feeding– Mouth– cardiac stomach-

can be extruded– pyloric stomach– pyloric caecae– Anus

– feed primarily on sessile organisms

Class Asteroidea True Starfishes

Page 9: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• Circulation– poorly developed with fluid filled chambers;

– no heart; coelom ciliated for fluid movement

• Excretion– no special organs

– general diffusion across body surfaces like tube feet

• Respiration– no special organs

– across body membranes

• Nervous System– associated with epidermis

– circular oral nerve ring with branches into arms

Class Asteroidea Systems

Page 10: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• Epidermis- outer surface; includes – mucous cells– epithelium– Pedicellariae- jawlike appendages of the epidermis

• can open and close• used to clean body of debris or put debris on body

• Dermis- includes – nerve cells– connective tissue

• Skeleton- below dermis– made of ossicles– lattice like connections– Calcium carbonate– with spines and tubercles

• Muscle layer- below dermis• Peritoneum that lines coelom

Asteroidea Body wall

Page 11: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• are dioecious; external fertilization

• usually 10 gonads; 2 in each arm

• have fissiparity- division of central disc into two animals

Asteroidea Reproduction

Page 12: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• free living larvae

• bipinnaria- first larval form develops into

• brachiolaria - shows development of arms

Asteroidea Reproduction

Page 13: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

Class OphiuroideaBrittle Starfishes

Page 14: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• 5 arms usually

• central disc well marked off, no branches of gut in arms

Class OphiuroideaBrittle Starfishes and Basket Stars

Page 15: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• no anus, no ambulacral groove

• madreporite on oral surface

• no suckers on tube feet, no ampullae (have a valve to control pressure)

• no pedicellariae• able to move quickly

and snake like hence their class name

Class OphiuroideaBrittle Starfishes and Basket Stars

Page 16: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

Class Echinoideasea urchins, sea bisquits, sand dollars

Page 17: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• no arms• skeleton is

fused into a solid test

• tube feet have suckers

• covered with moveable spines and pedicellariae

Class Echinoidea

Page 18: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

Class Echinoideaspecialized mouth structures - Aristotle's Lantern

Page 19: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

Class Holothuroidea Sea cucumbers

Page 20: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• body elongated in oral-aboral axis

• skeletal system reduced or absent

• no spines or pedicellariae

• mouth and anus at opposite ends of body

Class Holothuroidea Sea cucumbers

Page 21: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• no external madreporite

• tube feet with suckers• respiration through

anal respiratory tree• dioecious; single gonad• suspension or detritus

feeders • commensal

relationship with pearl fish

Class Holothuroidea Sea cucumbers

Page 22: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

Class Crinoidea Sea Lillies

Page 23: Phylum Echinodermata Introduction. About 6000 species, all marine Echinodermata

• most are extinct• most primative• all sessile, with

stalk that attaches to substrate

• have branched arms for filter feeding

• no suckers on tube feet

• no madreporite• no pedicellariae

Class Crinoidea Sea Lillies