For this year, the cycling calendar has been split up into the World Tour, Asia Tour, America Tour, Europe Tour etc. WorldTour are the big elite races but looking at the calendar there are some strange ones in there - Tour of Poland? Vattenfall Cyclassics? Good races but different levels to me. I don’t find it exactly clear what the purpose is. Neither does Bernie Eisel.
Even though races don’t look to be big deals where they fall on the calendar can make them so in terms of preparation for upcoming events. At the Tour of Qatar there are a lot of sprinters testing out their form and plenty of the cobbled classics guys getting the miles in.
Tour of California is important in terms of showing some sponsor love which is primarily why it yields an impressive roster.
That’s not to say certain races are just training rides and no one is looking for results - they all serve a purpose. Not least of all because there are ranking points available (and may be even more important in the context of this new WorldTour system).
In terms of team selection, for the WorldTour races, Protour participation is compulsory with a selection of procontinental teams of the organisers choice. Lesser category races should have a field made up of a percentage of protour, procontinental, continental and national teams. Full breakdown of percentages and other rules and regulation info can be found on the UCI website.
As for who rides where, I don’t know for sure how teams decide that. May be dependent on the rider and role within the team and down to a preference of what races they feel work best for them. Or they go where they are told to go in some cases, I’m sure some of that goes on but as I say, not sure how much say the rider has vs what team management want.