As you can see there are 1-31 ivs (indivisual points)(in pwo there are 32) each iv add one point to the stats, that means if a pokemon has 232 as attack stat and 1 iv it will have 233 as its attack (and if the pokemon has 31 as iv then 263 as its attack)
For more details on ivs :
http://bulbapedia.bulbagarden.net/wiki/ ... ual_values
EV (effort values) give 1 stat point for every 4 evs at level 100 which are gained when we differently based on which pokemon we defeat like if you defeat a caterpie it will give you 1 ev in hp stat so if you have stat (both normal and iv combined) as 252 in hp then for every 4 ev (in hp) you get 1 stat in hp, it becomes 253 (this is only at level 100), you can only have 510 ev's and only 255 ev's per stat like you can have only 255 ev's in hp (this number was reduced to 252 per stat in gen 6 but you dont need that as this game is based on previous gens) and each pokemon has certain ev for more details on ev and pokemon with certain ev in wild :
http://bulbapedia.bulbagarden.net/wiki/Effort_values
http://bulbapedia.bulbagarden.net/wiki/ ... alue_yield
As for the second, each pokemon are unique so they have different amount of experience to level up (2 charmanders will have require same amount of experience to level up while charmander and its evolution charmeleon require different experience to level up at same level) you can google about pokemon for more info.
