Echinoderm II

Echinoidea Class: Basics

• Test: CaCO3 skeleton

• Aristotles Lantern: Feeding(mouth)

• Large spines for locomotion

• Round and lack rays/arms

Urchin Basics

• have longest ossicles

• Ossicles modified into spines

• Longest podia

• Most rounded

Urchin: Digestive system

• Aristotle’s Lantern: made of 5 CaCO3 jaws supported by muscles

• Periproct: Waste elemination

Urchin: Hydrovascular system

• Gonopores: 5 found around madreporite (gamete release)

• Madreporite: pumps water into system

• Canals: pump water to ampulae

• Ampulle: connectors to podia

• Podia: feet

Urchin: External Anatomy

• long spines

• Long podia

• Pedicellariae: pincer like (Grabbers)

Urchin: skeletal anatomy

• Interambulacral Plates: large CaCO3 plates making majority of test separated by rows of Ambulacral plates.

• Ambulacral plates: smaller rows of plates that host most of podia

• Ambital plates: small plates that make up most of the other plates

• Primary tubercle: found on ambital plates attachment point of main spines

• Secondary tubercles: host pedicilariae (small spines)

• Apical Plate: Top plates

Sand Dollar External Anatomy

• Gonopores: release gametes

• Madreporite: pumps water

• Ambulacral/Petalloids: holds modified Dorsal podia lack sucker and used for respiration

• Food Groove: move food to mouth

• Peristome: mouth

• Lunules (5 slits): house ventral Podia

• Ventral podia: locomotion

Echinoidea class: Reproduction

• NO ASEXUAL REPRODUCTION

• Broadcast spawners

• Pluteus: larval stage

Holothuroidea Class: Basics

• elongated n soft

• Smaller, less dense ossicles

• No spines or arms

• Less Hydrovascular system for respiration

• Deposit feeders: scavengers consume organic matter, sand sifters

Holothuroidea class: Digestive system

• Tentacles: used for feeding

• Pharyngeal Bulb: main part of digestive system (house tentacles and starts esophogus) part of hydrovascular system

• Mesenteries: creates new intestine

Holothuroidea class: Hydrovascular system

Coelomic fluid: body fluid used as water to power movement as there is no true madreporite

Holothuroidea class: butts

Respiratory Trees: found inside the butt to absorb O2

Holothuroidea class: External Anatomy

• Papillae: covers the body wall

• Body wall: external surface

• Podia: Use for locomotion

• They are made of Collagen fibers and CaCO3 ossicles

Holothuroidea Class: Reproduction

• Asexual: fission

• Sexual reproduction: broadcast spawners

Holothuroidea Class: Reproduction

3 main larval stages:

• Auricularia: more pronounced arms

• Doliolaria: looks like barrel

• Pentactula: Mini cuc