Is ESD 2 required for the Chemical Systems Major?

[Higgs]

According to the handbook, none of the subjects leading to the Chemical Systems major have ESD 2 as a prerequisite, but ESD 1 is a prerequisite for CPA 1.

But according to this sample course plan: http://bsc.unimelb.edu.au/chemical-systems
It has ESD 2 listed as a "subject leading to the major".

So do I have to do the subject or not? And if not, will I be at a disadvantage for not doing it?

[Hancock]

In short, no.