Using Flowchart.com to Create a Dichotomous Key

We're currently in the taxonomic portion of the zoology course I'm teaching at Houston Community College.  I gave my students a test on invertebrates last week, and I attempted to use flowchart.com to do a quick pre-test review by creating a dichotomous key of the invertebrate phyla we studied in class.  Unfortunately, the flowchart.com server was working very slowly, so I improvised by drawing the dichotomous key using Microsoft Paint.  I didn't save that image, which I regret because I could have used it for a comparison.

Anyway, now we are moving on to Phylum Chordata, which includes the vertebrates.  I put together a dichotomous key of the chordates using flowchart.com.  I originally intended to include all of the groups I want the students to learn, but I realized that was a bit much to fit into one dichotomous key.  I will make separate keys for distinguishing subgroups of reptiles, birds, and mammals later.   

I'm thinking in class that I will have the students develop their own dichotomous keys, probably for different groups.  I tried to make this dichotomous key follow actual evolutionary history as best I could, although dichotomous keys don't necessarily have to do so.  We can cmpare the keys the students create in class to actual phylogenetic history.

I subdivided the ray-finned fish into the chondrosteons and the teleosts, because I want to make sure the students understand the difference between chondrichthyeans (e.g. sharks) and chondrosteons (e.g. sturgeons).  They're both cartilagenous fish, but they have different origins.

I do notice some shifting from the flowchart you make and what actually gets saved.  The arrow connecting "cartilagenous skeleton?" to "chondrosteons" is displaced in this image from where I placed it before saving and exporting the file.