Maria is Liz’s best friend throughout the show, and in many ways she reflects Liz, both as characters, and in terms of her relationship with Michael, which is often contrasted against Liz’s relationship with Max. Maria is usually portrayed as flighty and “wacky”, but also emotionally grounded. Her father left when she was quite young, and it’s easy to point out many ways in which she was influenced by her “hippy” mother, though she also regularly rebels against Mom and tries to plan to avoid mistaking the same mistakes as she sees in Mom’s life.
At the beginning of season two, Maria starts to affect a more glamorous personal style, with longer hair, (it’s later suggested that she convinced Isabel to help grow her hair out quickly,) and briefly becomes quite close to Max, doing her best to advise him well on winning Liz back and dealing with his alien worries, but she hilariously loses patience with his John F Kennedy obsession in “Ask Not” and whacks him with a heavy book-bag before lecturing him on Kennedy’s failings as a husband.
Maria is passionate about music, and she shares that passion with Alex, and later with Jim Valenti. Eventually her musical aspirations bring her to New York, but she finds that her new music label is asking her to compromise her artistic integrity and walks away. At the end of Season three, she’s the only member of the core gang not suspected to have alien genes, but chooses to leave town with the others in order to serve as moral support for Liz, and on account of her still-nebulous romance with Michael.