Biology Chapter 14: Echinoderms Flashcards

Questions and Answers

What does 'ambulacrum' refer to?

A type of larva

Radiating grooves where podia of the water-vascular system project (correct)

A structure related to respiration

A type of digestive gland

What is the ambulacral groove?

A groove along each ambulacrum containing rows of tube feet.

What are tube feet used for?

Locomotion, clinging, food handling, and respiration.

What is the function of the radial nerve?

To run the length of an arm and coordinate tube foot function. Signup and view all the answers

What are pedicellariae?

Minute pincerlike groups bearing tiny jaws. Signup and view all the answers

What is the role of papulae?

Increase surface area for gas exchange. Signup and view all the answers

What is a madreporite?

A sievelike structure that is the intake of the water-vascular system. Signup and view all the answers

What is the water-vascular system?

A set of canals and specialized tube feet for locomotion and food gathering. Signup and view all the answers

What are Polian vesicles used for?

Fluid reservoirs for the water-vascular system. Signup and view all the answers

What are ossicles?

Small calcareous plates bound by connective tissue. Signup and view all the answers

What are radial canals?

Canals along the ambulacra radiating from the ring canal. Signup and view all the answers

What do lateral canals connect?

The radial canal to the cylindrical podia along the sides of the ambulacral groove. Signup and view all the answers

What is the ampulla?

A muscular vesicle above the tube foot. Signup and view all the answers

What is the cardiac stomach?

The larger lower portion of the stomach that can be everted during feeding. Signup and view all the answers

What is autotomy?

The ability to detach part of their own body. Signup and view all the answers

What are pyloric ceca?

Digestive glands in echinoderms. Signup and view all the answers

What is the pyloric stomach?

The smaller upper portion that attaches to the digestive glands. Signup and view all the answers

What are somatocoels?

Posterior coelomic compartments that give rise to oral and aboral coeloms. Signup and view all the answers

What is an axocoel?

The anterior coelomic compartment. Signup and view all the answers

What is the hydrocoel?

The middle coelomic compartment that gives rise to the water vascular system. Signup and view all the answers

What is a bipinnaria?

A free-swimming, ciliated, bilateral larva of asteroid echinoderms. Signup and view all the answers

What are Ophiuroidea?

Brittle stars and basket stars. Signup and view all the answers

Match the following descriptions with their corresponding terms:

Echinoidea = Sea urchins, Sand dollars, Heart Urchins Asteroidea = Star-shaped with variable number of arms Crinoidea = Sea lilies, feather stars Holothuroidea = Sea cucumbers Signup and view all the answers

What are oral tentacles?

Modified tube feet around the mouth. Signup and view all the answers

What is a respiratory tree?

Composed of two long, many-branched tubes for gas exchange. Signup and view all the answers

What is a cloaca?

An opening that pumps seawater into the respiratory tree. Signup and view all the answers

What is an auricularia?

Free-swimming larva of class Holothuroidea. Signup and view all the answers

What are Cuvierian tubules?

Sticky, often toxic discharges expelled by Holothurians. Signup and view all the answers

What describes Holothuroidea?

Elongate body with no arms and unique respiratory tree. Signup and view all the answers

What defines Crinoidea?

Flower-shaped with stalked sea lilies and pinnules. Signup and view all the answers

What is significant about Asteroidea?

They have open ambulacral grooves and can be predators. Signup and view all the answers

What does 'triploblastic' refer to?

A type of embryonic development. Signup and view all the answers

What is the Echinodermata?

The name of the phylum that includes echinoderms. Signup and view all the answers

What is pentaradial symmetry?

A type of symmetry seen in adult echinoderms. Signup and view all the answers

What type of symmetry do echinoderm larvae exhibit?

Bilateral symmetry. Signup and view all the answers

What is a Deuterostome?

A type of embryonic cleavage. Signup and view all the answers

What are dermal papulae?

Fleshy dermal projections for respiration. Signup and view all the answers

What is Aristotle's lantern?

A 5-toothed jaw mechanism in Echinoidea. Signup and view all the answers

Study Notes

Echinoderms Overview

Echinoderms belong to the phylum Echinodermata, characterized by their unique features and structures.

Unique Features

Pentaradial symmetry: Adults exhibit this type of symmetry, while their larvae demonstrate bilateral symmetry.
Triploblastic: Echinoderms develop from three germ layers during embryonic development.
Deuterostome development: They exhibit deuterostomic cleavage patterns.

Key Anatomical Structures

Ambulacrum: Radiating grooves with projecting podia from the water-vascular system.
Ambulacral groove: Central groove of each ambulacrum containing tube feet flanked by movable spines.
Tube feet: Serve multiple purposes including locomotion, adhesion, feeding, and respiration.

Water-Vascular System

Madreporite: A sievelike structure serving as the entry point for the water-vascular system.
Polian vesicles: Fluid reservoirs connected to the ring canal of the water-vascular system.
Ossicles: Calcareous plates forming the body structure, often projecting spines.

Circulatory Elements

Radial canal: Canals radiating from the ring canal along the ambulacra.
Lateral canal: Connects radial canals to tube feet.
Ampulla: Muscular vesicle above tube feet aiding in movement and function.

Digestive System

Cardiac stomach: Can be everted for digestion and enzymatic breakdown of food.
Pyloric stomach: Connected to digestive glands where extensive digestion occurs.
Pyloric ceca: Digestive glands facilitating nutrient absorption.

Respiratory Structures

Papulae: Projections aiding gas exchange by increasing respiratory surface area.
Respiratory tree: Unique structure in some echinoderms for respiration, leading to the cloaca.

Defensive Mechanisms

Autotomy: Ability to sever parts of their body for defense.
Cuvierian tubules: Sticky, toxic structures expelled to deter predators.

Major Classes of Echinoderms

Asteroidea (Sea Stars): Have variable arms, open ambulacral grooves with suckered tube feet, and can prey by everting their stomachs.
Ophiuroidea (Brittle Stars): Characterized by a distinct central disc, autotomous limbs, and lack of suckers on tube feet.
Echinoidea (Sea Urchins & Sand Dollars): No arms with fused ossicle plates forming a "test," equipped with moveable spines and suckered tube feet.
Holothuroidea (Sea Cucumbers): Elongated body plan with no arms, utilized for respiration with a unique respiratory tree.
Crinoidea (Sea Lilies & Feather Stars): Flower-shaped bodies with arms bearing food grooves and tube feet, anchored by flexible appendages called cirri.

Larval Forms

Bipinnaria: Free-swimming, bilateral larva of asteroids.
Auricularia: Free-swimming larva of Holothuroidea that develops into adult forms.

Additional Concepts

Pedicellariae: Small pincher-like structures for defense and maintenance.
Dermal papulae: Flesh-like projections acting in respiration.
Aristotle's lantern: A specialized jaw mechanism found in Echinoidea for feeding.

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Test your knowledge of Echinoderms with these flashcards focused on chapter 14. Each card features a key term and its definition, enhancing your understanding of this fascinating group of marine animals. Perfect for studying and memorization.