I. Before discussing the major phyla:
II. As a class, discuss the groups that the student teams have come up with. Ask them to describe why they put certain animals together.
Next, show the students the "correct" groupings of the animals (a key with the proper groups will be provided: see below). These are the groups that scientists have come up with. Ask the students to describe the main "traits" or similarities within each group (i.e., those things that all the animals in a group have in common). The students will not be able to come up with all of the characteristic traits of each phylum just by looking at photographs. But it is important to stress to them that they will be able to experience the same process that scientists go through when they group organisms.
III. Dichotomous Key (also contained in PDF file CrittersClassified.pdf) Hand out pictures of 3 different animals, from 3 different phyla, to the teams again. The students will work through the dichotomous key to discover the name of the phylum that each animal belongs to.