Echinoderms

Summary
A lesson on the ocean animals known as echinoderms (sea stars, sea urchins, and sea cucumbers). The reading is accompanied by true/false questions.

Objectives
• To introduce students to the biology of ocean animals called echinoderms (sea stars, sea urchins, and sea cucumbers).

Suggested Grades
6th Grade
7th Grade
8th Grade

Excerpt
The ocean is home to different creatures from animals that are found on land and the phylum of echinoderms is a prime example. The phylum Echinodermata is a scientific classification of simple animals including sea stars, brittle stars, sand dollars, sea urchins, and sea cucumbers. While these are species that perhaps sound familiar, there are approximately 6,000 species of echinoderms found in the ocean worldwide.

One unique feature of echinoderms is the radial symmetry of their bodies. Humans and other mammals have bilateral symmetry. The prefix ?bi? means two and ?lateral? meaning side of the body. With bilateral symmetry humans and other mammals, birds and fishes have two equivalent sides relative to a middle line in the body. Echinoderms have a body that can be divided into five parts or segments; the most obvious example is the sea star with its five arms that radiate out from the center of the body. Some species of sea stars have more arms but the body can still be divided into five major segments.

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