Ross Geller is a bit of the nerd of the group of Friends, but definitely a member as his sister is Monica and Chandler was his friend from college.  Ross startts off as a paleontologist at the New York Museum of Natural History and later becomes a professor at NYU.

Ross is infamous for his on-and-off again relationship with Rachel, that ends with them having a kid together and mostly in the on-stage.

Of course, we can't write a bio for Ross without mentioning his three failed marriages to: lesbian Carol (who he had a kid with), Emily, and Rachel (which got annulled).