People used to get there last names from what they did in the community a LONG time ago my last name is Peach so someone in my family was probably a peach farmer or something that involves peaches

My opinion, I think someone just made them up one day. Then everyone started to do it, because too many people would just have the same name :O

Probably also because as the population expanded, people couldn't just go by "John" anymore.

a lot of last names are to do with what your ancestors were doing as a job such as smith being a blacksmith and Taylor being a tailors i beleive

It isn't unknown or hard to find out how... if your last name is smith then your ancestors were smiths, if your last name is wood then you were someone working in a forest. However they vary in meanings, some surnames are funny from those times....

(that's just an example, for the guy who's last name is peach, probably a peach orchard... It could mean sinner as well, but because of there humour your name could mean someone too pious for his/her peer group )

(my surname is wood, so it could mean a forester like I said... but seeing as every one lived near woods. The old spelling was wode, so it probably came from the saxon wode which means crazy and wild, a warrior. That's why most wood heraldic arms have a semi-naked savage with a club... serious )
And surnames were necessary when polling and personal taxation were introduced

idk mine is brick so im guessing my ancestors were masons

-Kreayshawn wrote idk mine is brick so im guessing my ancestors were masons

Your ancestors were bridge keepers, or lived near a bridge/causeway, olde english is different so it seems obvious but it isn't

I was told that last names were usually placed because of proffesion, or family heritage.

Of course this didn't take place any time close to current time, but hopfully you get the gist.