Fire types probably obtained a temperamental and wild nature due to their relative frailty, especially those with external flames. See the Charmander line - literally holding their life on their tails, if dex entries are to be believed. Following the anime's interpretation, simply getting caught in the rain might spell doom for a fire-type, or at least cripple it with too much exposure.
Grass types likely wouldn't prosper as well in climates without much greenery. Counter-examples might include Maractus and Cacnea/Cacturne, who are probably hardier and conserve water very well, like the vegetation they are based off of. Grass-types are probably some of the longest lived 'mons, as long as they have access to water and sunlight.
Ground, Rock, and Steel types live for a hella long time, considering that they likely don't have to sustain themselves as much as other types. Eat some rocks, you're good to go. Hell, something like a Roggenrolla or Geodude is probably just a rock animated with the "magic" that the Pokemon world uses.
Bug types have rather variable life cycles, I'd imagine. The Route 1 three-stage bugs probably don't last long at all, keeping in line with their real-life counterparts and hasty evolutions. Meanwhile, Scizor and Forretress are hardy and long-lived(near to indestructible, really), and Shedinja is an immortal anomaly that should not exist, and likely would not if not for Poke Ball systems "harnessing" it as it is attempting to depart. Other bugs lie in between.
Should I continue?
