I have a dog that i love so much.  But it takes a lot of comittement.
Yes, they are alot of work and commitment.  They were the first species to ever be domesticated.
yes nobody seems to know how long dogs have been with human, at least thousand of years.  Do you have a dog?
Yes, they say that all dogs originated from wolfs but it is hard to picture my little Mia(chihuahua) coming from the wolf.  LOL
Yes,  I don't believe there are wild dogs by now.  But dog races can be so different one from another, 
Yes, they are now selectively bred for specific characteristics, behaviors, and physical attributes
I don;t even know how a grans danes recognize a chihuahua as it own specie, they look so different, I don't believe that happens with other species
yes, its very interesting.  Also interesting how attuned dogs are to humans now b/c of being around us for so long.
Ye my wonderful chocolate lab is very sentive to my moods, he is the most adorable dog in the world (not that I am biased LOL)
My Mia may beat him their! =) It is also neat how they can thrive on a starch rich diet that would be inadequate for other canine species