For ADCs, Caitlyn is the prime example of a long range poking lane bully, and something like Kog'Maw, Twitch, or Tristana represent true hyper carry based ADCs.
For top laners, Nasus is the true definition of hyper scaling, ranged champions offer bullying capabilities that Jax can't possibly keep up with, and champions like Alistar or Maokai are almost designed to defend others.
Finally, there are a number of Junglers who fill different niches. True carries like Yi, true tanks like Cho'gath, Fighters like Jarvan, not to mention that anyone with a knock back has incredibly different ways of approaching ganks/being useful late game that Jax literally doesn't have access to.
I'm not sure what you mean when you say "Just starting to play ranked after honing my skills somewhat in normal", but basically you want to have a grasp of general classes of champions and what they are capable of. For example, when I say "Ezreal ADC", what should pop into your mind is that he has burst, long range, and an escape, ultimately making him an extremely well rounded pick since he doesn't have a hard weakness. On the other hand, when I say "Caitlyn ADC", what should pop into your mind is her long range, bullying capabilities, and escapes, but as a weakness she isn't as strong late game. She's a specialized champion, designed around her ability to dominate in lane but generally tend to fall off late (relative to other ADCs) as her weakness.