After the trays on Living, non-living I put together this unit on Vertebrates and Invertebrates. These are straight out of Karen's Albums.
First you introduce to the child the concept of Vertebrates. For us we read these books on Vertebrates and Invertebrates and D was hooked. (Sorry, my Amazon affiliates widget is not working, so you will have to bear with only these pictures for now!)
The first tray is the concrete on Vertebrates. I used some animal replicas to represent all five groups.
Next is the abstract representation for Vertebrates. I made these cards using google images. I made these as three part cards, but for now I just put in the control cards for this tray. As you can see I included a picture of D for fun as "human". D got such a kick out of this!
Next are the concrete and abstract for Invertebrates.
Once she is done working with these trays, I would mix up the contents and let her sort the vertebrates and invertebrates into their respective groups. Also I would introduce the three part cards and let her work on these. For now, this is how it is laid out in our shelf.