Echinoderms Water Vascular System Quiz

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Questions and Answers

What role does the madreporite play in the water vascular system of sea stars?

Pressure regulation and simple filter

Does the sea star possess a heart or circulatory system? How do you suppose nutrients and oxygen are distributed to the body tissues?

Internal water canals branching from a central ring canal; O2 & nutrients are distributed via water pumped throughout

Does the sea star possess an excretory system? How do you suppose metabolic wastes are eliminated from the body?

No excretory system; Mostly excretes uric acid and waste via diffusion through tube feet

Why are ossicles classified as an endoskeleton?

They are hard body structures on the inside of the skin Signup and view all the answers

How do sea cucumbers defend themselves given their loss of sharp spines?

Evisceration -> shooting water/guts out of digestive system Signup and view all the answers

What characteristics do sea cucumbers possess that would cause zoologists to group them in the same phylum with other echinoderms?

Pentaradial symmetry & a water vascular system Signup and view all the answers

Why are chordates and echinoderms similar?

Similarities in embryonic pathways Signup and view all the answers

What are the advantages of an endoskeleton?

Provides support without necessarily affecting the growth of the animal Signup and view all the answers

What is unique about the madreporite of sea cucumbers (class Holothuroidea)?

The madreporite lies free in coelom Signup and view all the answers

What is the class of Asterias?

Class Asteroidea Signup and view all the answers

What is the class of sea lilies and feather stars?

Class Crinoidea Signup and view all the answers

What is the class of sea cucumbers?

Class Holothuroidea Signup and view all the answers

What is the class of brittle stars?

Class Ophiuroidea Signup and view all the answers

What is the class of soft, cylindrical body with leathery skin?

Class Echinoidea Signup and view all the answers

What is the class of body containing a stalk with mouth and anus on the oral surface?

Class Crinoidea Signup and view all the answers

What is the class of body plates fused into a solid test with long, movable spines?

Class Echinoidea Signup and view all the answers

What is the phylum and class for a starfish?

Phylum: Echinodermata; Class: Asteroidea Signup and view all the answers

What are the main components of sea cucumber anatomy?

Mouth, Pharynx, Intestines, Ring Canal, Respiratory tree, Gonad, Anus Signup and view all the answers

What is the function of sea star spines?

Calcareous projections for protection and support Signup and view all the answers

What is the function of sea star pedicellariae?

Pincerlike structures believed to kill small organisms that might settle on body surfaces Signup and view all the answers

What is the function of sea star dermal branchiae?

Gas exchange and exertion through simple diffusion Signup and view all the answers

What is the function of the sea star mouth?

External opening to cardiac stomach (through a short esophagus) Signup and view all the answers

What is the function of the sea star madreporite?

Porous entrance to the water vascular system that serves as both pressure regulator and simple filter Signup and view all the answers

What is the function of the sea star ambulacral grooves?

Radiate from the mouth to the tip of each arm and house the tube feet Signup and view all the answers

What is the function of sea star tube feet?

Locomotion and prey capture Signup and view all the answers

What is the function of the sea star cardiac stomach?

Can be everted through the mouth to envelop prey Signup and view all the answers

What is the function of the sea star pyloric stomach?

Receives secretion of digestive glands for chemical digestion Signup and view all the answers

What is the function of sea star digestive glands?

Secrete digestive enzymes for breakdown of food; absorbs and stores food Signup and view all the answers

What is the function of sea star rectal ceca?

Small, branched 'trees' that increase the surface area of the intestine for more efficient nutrient absorption Signup and view all the answers

What is the function of sea star gonads?

Produce gametes for reproduction Signup and view all the answers

What is the function of the sea star ring canal?

Portion of water vascular system encircling the mouth Signup and view all the answers

What is the function of sea star radial canals?

Portions of water vascular system emanating from the ring canal and leading into each arm of the sea star Signup and view all the answers

What is the function of sea star ampullae?

Provide hydraulic pressure for movement of the tube feet Signup and view all the answers

What is the function of sea cucumber tentacles?

Food collection Signup and view all the answers

What is the function of the sea cucumber ring canal?

Water vascular system encircling the junction of pharynx and stomach Signup and view all the answers

What is the function of sea cucumber ampullae?

Provide hydraulic pressure for movement of the tube feet Signup and view all the answers

What is the function of the sea cucumber pharynx?

Transports food from mouth to stomach Signup and view all the answers

What is the function of the sea cucumber madreporite?

Entrance to the water vascular system that serves as a pressure regulator; floats freely within coelom Signup and view all the answers

What is the function of the sea cucumber cloaca?

Pumps a ventilating current of seawater in and out of respiratory trees Signup and view all the answers

What is the function of the sea cucumber anus?

Regulates digestion of undigested food (feces) from the body Signup and view all the answers

Study Notes

Echinoderms Overview

Echinoderms include diverse marine species with a water vascular system, uniquely adapted for movement and feeding.
Key classes include Asteroidea (sea stars), Crinoidea (sea lilies), Holothuroidea (sea cucumbers), Ophiuroidea (brittle stars), and Echinoidea (sea urchins).

Madreporite

Serves as a pressure regulator and filter within the water vascular system.
In sea cucumbers, it lies freely in the coelom, differing from its fixed position in other echinoderms.

Circulatory System

Echinoderms lack a traditional heart and circulatory system.
Nutrients and oxygen are distributed through internal water canals connected to a central ring canal, using hydraulic pressure.

Excretory System

Echinoderms lack a distinct excretory system.
Metabolic wastes are primarily excreted through diffusion via tube feet.

Endoskeleton and Ossicles

Ossicles are hard structures that form an internal endoskeleton, providing support while allowing for growth.
The water vascular system and pentaradial symmetry unite echinoderms, including sea cucumbers.

Defense Mechanisms

Sea cucumbers defend themselves through evisceration, expelling water and internal organs to escape predators.

Sea Star Anatomy

Features include a mouth leading to a cardiac stomach, equipped with tube feet for locomotion and prey capture.
The pyloric stomach receives digestive secretions for further digestion.
Gonads produce gametes for reproduction; the rectal ceca enhance nutrient absorption.

Functions of Various Structures

Pedicellariae: Pincer-like structures that eliminate small organisms from the surface, keeping skin free of parasites.
Dermal Branchiae: Facilitate gas exchange and waste excretion through diffusion.
Ampullae: Provide hydraulic pressure, enabling movement of tube feet.

Sea Cucumber Anatomy

Characterized by a mouth, pharynx (food transport), intestines, gonad, and a cloaca for ventilating seawater.
Tube feet movement is supported by hydraulic pressure provided by ampullae.

Reproductive Structures

Gonads generate gametes, influencing reproduction, demonstrating variations in sexual reproduction methods across echinoderm classes.

Summary of Classes

Asteroidea: Sea stars; recognized for their multiple arms and retractable stomachs.
Crinoidea: Sea lilies and feather stars; possess a stalk and mouth/anus orientation on the oral surface.
Holothuroidea: Sea cucumbers; have a soft body and specialized tentacles for feeding.
Ophiuroidea: Brittle stars; known for their brittle arms and small size.
Echinoidea: Sea urchins; body plates fused into a solid test with movable spines.

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Description

Test your knowledge on the water vascular system of echinoderms, particularly sea stars. This quiz covers various aspects such as the role of the madreporite and the distribution of nutrients and oxygen. Perfect for students studying marine biology or related subjects!