For students to complete additional experiments on species of invertebrates, they should first be able to recognize the different major classifications. Design cards for different species of invertebrates, with pictures of the species on the front and the phylum/subphylum listed on the back, as well as a basic description. For example, a picture of a starfish would have the classification "echinoderm" along with an outline of common features and habitat information. After students are familiar with the different classes of invertebrates, divide the students into groups of three or four. Give them a worksheet listing different species and have them assign the species to its phyla or subphyla.
Observing an earthworm can help students develop an understanding of the characteristics of annelids. Give each student a live earthworm on a moistened paper towel in a dissection pan. Let students observe the earthworm, taking notes on its overall appearance as well as its movements. Have them determine the anterior and posterior sections, measure the worm's length and count its segments. Evaluate touch stimulation by placing the earthworm across wet and dry paper towels laid side by side. Students then observe which paper towel the earthworm moves toward or away from. Test the effects of odor using a cotton swab soaked in rubbing alcohol. Place the swab first at the anterior of the worm and then the posterior to gauge its reaction.
Use two halves of a hollowed potato to create an insect trap. Have students place their traps in soil depressions in different locations. Each day students check their traps for insects, collecting them in petri dishes or glass jars for closer observation. Using a magnifying glass, students can analyze the insects, noting the type of insects collected and their appearance. Ask students to analyze the reasons the insect entered their trap (i.e. for food, shelter or moisture), if there is a prey/predator relationship between any of the insects and how the location of the trap affected the types of insects collected.
The simplest and smallest of animal species, protozoa are single-celled animals that move, breathe and reproduce just like their multi-celled counterparts. Due to their small size, protozoa are difficult to observe. Lead students in a discussion of the two main types of protozoa, amoebas and flagellates. Discuss their characteristics, habitats and specific behaviors. Use a microscope and prepared slides of amoebas and flagellates so students can observe this class of invertebrate. Have them draw what they see and identify whether it is an amoeba or a flagellate.