I was wondering about the life cycles of the main exemplar races of the planes, especially how they acquire new blood, so to speak, and how they transform their members into new forms. Do they require petitioners? Do they spontaneously generate from the plane? Do they mutate naturally or do they have some esoteric process of transformation?
Thanks very much!
It varies from race to race.
I think that there's another thread or two about it if you search.
[edit]
phew, there's a lot of threads on this site! I got to page 14 of 'RPG Discussion' before giving up.
Here's 3 threads you might find interesting. There's a lot more on fiends than on anything else but I guess that figures.
http://planewalker.com/forum http://planewalker.com/forum http://planewalker.com/forum
Slaad - The spawning stone effects their ability to procreate but their method of breeding is a sort of parasitic transmission from the blues and reds.
Modrons - Created from energy drawn from the central pool. A new one is created every time another is killed.
Thanks, everyone! 
A related question:
What happens to elementals when they die? are there elemental petitioners? Most elementals are neutral, but arcomentals can be good or evil aligned. Does this mean sunnis will go to elyisum when she dies?
Same thing also for various genies. They apparently don't have any deities, but all of them are somehow aligned. Will the efreet sultan end up in Baator?
And ofcourse, if they do, what will they look like? Normal humanoid petitioners or elemental type petitioners?
I didn't want to open a new thread for this question, but it's been bugging me for a while.
Elementals are a part of their respective planes. When they die, they die dead and don't go anywhere. (to my understanding. Wait for Rip to find the thread 
)
Elementals are spirits who animate elemental matter around them. If you destroy their animating spirits, they work just like outsiders - they merge with their home planes and they have no portion of their selves left to go anywhere.
Genies are outsiders. Like elementals, fiends, celestials, and gods, they don't have separate souls; they are souls, and if you destroy them they merge with their home planes and no longer have anything resembling a consciousness.
Genies do have gods. The Tales of the Lamp boxed set listed the gods each genie race worshipped (usually a mixture of Zakharan gods and other planar powers like Kossuth, Istishia, Akadi, Grumbar, and the archomentals). A god of salamanders and efreet, Kaelthiere, is described in Complete Divine and Defenders of the Faith. They don't have any separate souls to go to them, however.
It seems to be like this:
Person
Dead
Petitioner
Bigger, stronger petitioner
weediest thing in exemplar race
get promoted when the bigger things (like the power you serve, or just much more powerful [insert exemplar type here]) in the chain decide you're doing well
Keep getting promoted.
Generally the process is pretty spontaneous, the Fiendish Codex series tries to over-explain it a bit for devils saying they have strange sac things that hold all the other forms and whatnot but really these are the planes, if the big superiors think you've been a good spinagon and deserve to be turned into an ice devil you turn into an ice devil. Probably in a painful, gory and fast transformation.
I think when natives to the outer planes die they merge with their plane.
It writes and designs dungeons, adventures and encounters. Do not feed after midnight.