Classification of an Echinoderm

Dill, Henry                              Kennedy High School
                                         1-312-838-5225
                       

Objective

To understand how the starfish relates to its classification. 

Materials

  Preserved Echinoderms, spiders, and other invertebrates and vertebrates. 
  Microscope projector. Overhead projector
  Slides for production including the arthropods and echinoderms. 
  Illustrations of the starfish.
  Animals with exoskeletons.
  Chart with the family tree of living organisms.

Recommended Strategy

 1. Students will observe the changes in forms, behavior, and feeding 
    characteristics. 
 2. Ask the students, "Why can a starfish regenerate a missing arm?" 
 3. Students will be given an opportunity to observe the various parts of an 
    echinoderm. 
 4. Discuss the historical background of a starfish. 
 5. Explain how the animal obtain its food.          
 6. Students will be ask to use the microscope to identify different structures of 
    the organism. 
 7. Students will be asked, "Of what survival value is metamorphosis?". What is 
    metamorphosis? 
 8. Students will be asked to explain how starfish reproduce. 
 9. After all students have identified the various parts of a starfish, they will 
    compare the classification of the starfish with other invertebrates. 
10. Students will show in which ways the echinoderms are similar to the chordates. 
     
Activities

Students will give three characteristics of each animal, so they can identify the 
organism. All students will discuss the relationship between the arthropods and 
echinoderms. 

Exercise 1: 
Have students view how the echinoderms develop. 

Exercise 2:
The students will dissect the dorsal side of the starfish to expose the internal 
structures. 

Evaluation

Have students write an essay entitled:  How Invertebrates Live.  The students will 
observe the shift in body plan established in lower groups to bilateral symmetry in 
the larva stage to secondary radial symmetry in the adult stage. The students will 
compare these characteristics to the insects. 

References

Laboratory Guide for the Biology Sciences, Modern Biology, and the Sciences of 
Biology. 

If you want to see this experiment performed, you can come to Kennedy High School. 
Materials can be obtained at the American Science Center and the starfish, spider, 
and the centipedes can be obtained from Ward's catalog. 
 
Summary

Insects are the most numerous group of animals on earth today. They have survived and 
flourished by combining a high reproductive rate with thousands of individual 
adaptations to different environments. The phylum Echinodermata consists of animals in 
which bilaterally symmetrical larvae undergo metamorphosis into adults with 
pentaradial symmetry. All echinoderms are marine.