Phylum Echinodermata, Class Echinoidea Flashcards

Study Notes

Phylum Echinodermata

Known as "spiny skin" organisms, characterized by their hard, calcareous exoskeletons.
Includes various marine animals, exhibiting radial symmetry in adult forms.

Class Echinoidea (Sea Urchins)

Commonly referred to as sea urchins, which are small, spiny creatures inhabiting ocean floors.

Spines

Non-movable projections that serve as protection and aid in mobility.
Made of calcified material, contributing to the exoskeleton structure.

Teeth

Located in the oral cavity, specifically designed for grinding food.
Integral part of the feeding mechanism in sea urchins.

Lip

The term is left undefined but refers to potential structures around the mouth.

Anal Plate

Positioned on the "top" of the sea urchin's body.
Plays a role in the anatomy and excretory function of the organism.

Madreporite

A sieve-like structure that connects the water vascular system to the external environment.
Critical for regulating water intake and pressure within the system.

Gills

Extensions of the body designed for respiration, featuring thin-walled blood vessels.
Facilitate efficient absorption of oxygen from surrounding water.

Mouth

The oral opening through which sea urchins ingest food.
Located on the underside of the body, highlighting the organism's feeding behavior.

Buccal Podia

Oral tube feet that assist in feeding and movement.
Enable sea urchins to grip surfaces and manipulate food.

Anus

Muscular opening at the end of the rectum for waste elimination.
Essential for digestive functions and waste management.

Genital Plates

Larger plates that encompass reproductive structures, including the madreporite.
Facilitate water entry into the water vascular system through specialized pores.

Aristotle's Lantern

A unique feeding structure made up of muscle-operated calcareous plates and jaws.
Provides an effective mechanism for sea urchins to scrape algae and other organic materials.

Trophic Differences Between Sea Stars and Sea Urchins

Sea stars are relatively unselective carnivores, consuming mollusks, crustaceans, and small fish.
Sea urchins primarily feed on algae and organic material, playing different ecological roles in their habitats.

Description

This quiz focuses on the Phylum Echinodermata and Class Echinoidea, specifically sea urchins. Learn key terms and definitions related to these marine organisms through flashcards. Perfect for students aiming to deepen their understanding of marine biology.