The Relationship Question

One of the insinuated questions I see in my students' science textbooks and workbooks is, "How is (a.) related to (b.)?"

Example: Last week I asked my 9th grade Biology students to describe how Phylum Cnidaria was related to Classes Scyphozoa and Hydrozoa. I had not previously described Phylum Cnidaria as a whole, but I had taught the students about the two classes, and told them that Scyphozoa and Hydrozoa fell under Cnidaria. We had also discussed the 7 levels of the classification system last semester. Nevertheless, the students did not understand what I was asking them. In hindsight, I should have spent more time describing the phylum first, but even without that detailed knowledge, I expected them to be able to tell me that the Classes were contained within the Phylum, and thus shared many characteristics. Part of the problem, I believe, was due to  the nebulous nature of the word "related."

When we talk about relationships, we are generally talking about connections and levels of intimacy. If I say I am in a relationship, I mean that I have found a person to share a significant amount of time, space, emotions, and the events of my life with. If I say I have a good relationship with my boss, I mean that we get along, there is mutual respect, etc. But the word "relationship" also refers to the hierarchy among two or more people--or objects, ideas, and scientific terms. If I presented the question, "How is boss related to employee?" I would not be asking about the respect, or whether or not the boss likes his employee. I would want to know where the lines of equality are drawn. Does the employee stand above the boss, below the boss, or across from the boss? Does one stem from the other? Does the job description of one encompass more than the other; are the responsibilities of one contained within the scope of the responsibilities of the other?

Likewise, when I ask how Phylum Cnidaria is related to Classes Scyphozoa and Hydrozoa, I want to know where the hierarchy exists. Are Cnidaria, Scyphozoa, and Hydrozoa each a different group with characteristics that distinguish it from both of the other groups? Or does one encompass both the others? Are the characteristics of Phylum Cnidaria expansive enough to include all the characteristics of Scyphozoa and Hydrozoa? Is Phylum Cnidaria a group which contains Scyphozoa and Hydrozoa? Or do Scyphozoa and Hydrozoa contain Phylum Cnidaria?

This is where graphic organizers can prove extremely helpful, and can give a visual to the ideas of being above, below, within, or across from. But perhaps the word "related" needs to be particularly defined as well. I have seen students struggle even with the graphic organizers, and I now realize that they must have been struggling for lack of an explanation of relationship and hierarchy, which is necessary for the interpretation of diagrams.