I will sit for my comps in a little less than a year. At my school PhD comps include a written and a oral portion. About six weeks before the big date each person on my committee of five professors will give me two questions. In theory one of these will be closely related to my own research interests while the other will be a broader question. I'll have a few weeks to compose my answers to these questions which I will then return to my committee members. After they have had a chance to review my answers we will have the oral portion of the exam. Lately these seem to run around two hours. The questions that you are asked in this portion can be over just about anything but usually are weighted towards the students research interests.
To get ready for this I have made up a reading and study list to try and make sure that I know everything that I personally feel a person with a PhD in biology should know. I am probably over doing it but when else am I ever going to get to study so much across such a broad range of topics. Since I have a full year to prepare I can really cover an amazing amount of information.
Each morning I am reading and summarizing two article from my reading list. My list has about 250 articles plus another 40 or so book chapters. I put it together from reading groups and classes that I have had over the last year as well scouring a lot of online resources like:
(I'll post it later this week once it is cleaned up and alphabetized)
I am also reviewing Campbell and Reece a few hours each week. My main goal with it is to be able to explain most of the real groundbreaking experiments that allowed us to reach the level of understanding that we have today. I also feel like it covers some of the basic processes that are outside of my research area but that I should still be able to explain to someone else (photosynthesis, gene regulation, etc.)
On the entomology front I am reading two books. Each evening I read either Biology of Coleoptera by Crowson or The Evolution of Insects by Grimaldi and Engel.
I hope that this level of preparation is a bit more than most at my school and that it will allow me to fly through comps with no problem. I'd love to hear how anyone else who has already been through this process prepared for comps and how you felt about it once it was all said and done.