IIRC broccoli, couliflower and cabbage come from the same plant, in a similar way that great danes and mastiffs come from the same animal.
So I read. Apparently, a type of wild mustard, of all things. But a Great Dane and a Mastiff are really, really, similar. I look at them both and I see dogs. Nothing difficult to explain there.
But Broccoli and cabbage? It seems to me that is a great example of speciation with radical morphological change associated, and all within a very short time period. It isn't just a case of fruit flies that don't think each other are sexy any more. I wonder if anyone has studied how much difference there is, genetically, between brocolli, cabbage, and their wild mustard ancestors.
A word on the scientific method.
Observation 1: That thing looks like it was designed for a purpose.
Observation 2: That thing is so complicated, it couldn't have come together by chance.
Hypothesis: That thing really was designed for a purpose.
Experiment: Let's see if we can see anything that complicated that comes together by random processes guided by natural selection.
Theory: Those complicated things that look like they were designed demonstrate the handiwork of one or more designers.
Now, the experiment hasn't been completed. In fact, there are some experiments that would tend to suggest that it is possible to put together very complex things randomly, which tends to cast doubt on the hypothesis. However, none of the experiments done to date are definitive in this regard. Therefore, ID is an unconfirmed hypothesis.
As such, talking about it in science classes doesn't seem far fetched to me, as long as it is taught as what it is, an unconfirmed hypothesis. Meanwhile, teaching the age of the Earth as confirmed hypotheses seems appropriate. And teaching the mechanisms of evolution as confirmed hypotheses seem appropriate.
With respect to Dover, Pennsylvania, I am leaning to the view that the resolution is very bad, for two reasons. First, it has some inaccurate portions in the manner in which it characterizes evolution. Second, it shouldn't be necessary. Science teachers should be free to talk about any unconfirmed hypotheses they want to. They can't teach "God created the Earth" because that would be asserting something that can't be confirmed. But they ought to be able to teach, "Some people think that this particular structure is too complicated to be explained by natural selection. Most scientists disagree. However, to date, there is no conclusive evidence either way."
A note on the word "random". I spent a great deal of time in graduate school struggling with courses that involved "random variables" and "random processes". Those classes were really hard, but by any definition I used in any of my classes, evolution is a random process. Why the knee jerk reaction against the word "random"?