U5Ip

There are 9 Organisms in Nine Different Phyla.

Organism Phyla Dichotomous Key (steps) Classification

1 CNIDARIA Symmetry is radial or bilateral

Radial symmetry; lacks a well defined head

No spines or arms present

Saucer-shaped, transparent body with tentacles, free floating Class Scyphozoa

2 MOLLUSCA Symmetry is radial or bilateral

Bilateral symmetry (similar right and left body halves; anterior head end and posterior tail end)

Animal has no apparent skeleton, or may have an exoskeleton (hard outer covering), or may have a shell (invertebrate)

Hard outer covering, exoskeleton, or shell; not worm-like

No jointed appendages

Soft body, obvious head

May or may not have a shell; head with tentacles, small eye or eye spot Class Gastropoda

3 ANNELIDA Symmetry is radial or bilateral

Bilateral symmetry (similar right and left body halves; anterior head end and posterior tail end)

Animal has no apparent skeleton, or may have an exoskeleton (hard outer covering), or may have a shell (invertebrate)

No hard outer covering, exoskeleton, or shell; worm-like

Body is segmented ANNELIDA

4 ARTHROPODA Symmetry is radial or bilateral

Bilateral symmetry (similar right and left body halves; anterior head end and posterior tail end)

Animal has no apparent skeleton, or may have an exoskeleton (hard outer covering), or may have a shell (invertebrate)

Hard outer covering, exoskeleton, or shell; not worm-like

Jointed appendages

One pair of antennae or none, no large claws

Three pairs of legs; wings present Class Insecta

5 PORIFERA Symmetry is irregular (neither bilateral or radial); aquatic; body structure without tissues or organs PORIFERA

Echinodermata Symmetry is radial or bilateral

Radial symmetry; lacks a well defined head

Spines or arms present

Five arms present, body surface knobby Class Asteroidea

7 CHORDATA Symmetry is radial or bilateral

Bilateral symmetry (similar right and left body halves; anterior head end and...