When you look at the books the first thing you notice is how thick the pathfinder book is in comparison to the 3.5 book. 3.5 D&D is 316 pages long, Pathfinder however is 574 pages. The main reason for this is pathfinder does not separate its player and GM
So The first thing you do in either pathfinder or 3.5 is choose your race. The base races in both games are Human, Halfling, Gnome, Half Orc, Dwarf, Half elf, and Elf. In pathfinder the races are much more powerful. However even though they are more powerful in comparison with their 3.5 counterparts they are closer in power level in comparison with each other. From a strictly power gamer viewpoint there was little reason to play some races in 3.5. Halflings and Half elves in particular got the shaft in power level.
In pathfinder each race has +2 to two different stats and gets a -2 to one they also have a variety of unique abilities. for instance dwarves get bonuses to appraise skill checks, attack bonuses against orcs and goblins, bonuses to poison and spell saves, defense bonuses against bull rushes, perception bonuses in relation to stonework, and automatic proficiency with any weapon with the dwarven keyword and battleaxes, heavy picks and war-hammers.
The exceptions to the +2 to two stats are humans and the half humans, they all get +2 to a stat of their choice. Just like everything in pathfinder, its very close to 3.5 but slightly more tunned.