Yes, there is a lot about the Sylvari that puzzles me. My personal explanation is that Mordremoth shaped them based on human physiology - why, though, I have no clue. ;)Nearly two hundred and fifty years ago, a human soldier named Ronan found a strange seed during his journeys and tucked it away to give to his daughter when he returned home. Sadly, by the time he reached his village, it had been destroyed, wiped out by the White Mantle. Ronan planted the seed upon his family's graves instead.You will be able to find where that came from here. The tree soaked up the "human essence" and [it](https://wiki.guildwars2.com/wiki/Avatar of the Tree) got info/data on physiology so that's why the sylvari are like humans.