levite

Let's leave aside for a moment the question of peyot (that's the name for those side-curls you mentioned), what you see at work in the black and white dress amongst traditional Orthodox men (Modern Orthodox men generally don't wear the black and whites, except sometimes on shabbat and festivals) is actually not Jewish law, it is custom of comparatively recent standing, based in an ascetic stream of thought called mussar, which means "knowledge passed along and received [i.e., from generation to generation]."

The custom in mussar, originally, was that a person should dress modestly, in simple colors and fabrics, in order not to divert their attention, or the attention of others, onto things of this world, but rather to allow their attention to more easily rest on things of the spiritual. In the 19th Century, this teaching became paradoxically conflated with a folk custom among Hasidim in Eastern Europe to dress as much as possible like a lord on Shabbat, and they decided that "a lord" indicated a lord in Eastern European lands during the time of the founding and first great flourishing of Hasidism, which is to say, the 18th Century. So even today, you find many Hasidim dressing not only in black and white, but in the long black coats, knee stockings, fur hats, and so forth of 18th Century Polish nobility.

Nonetheless, the black and white clothes all the time did not become dominant in the traditional Orthodox world until midway through the 20th Century, when, due in part to the mass emigration of Eastern European Jews to the US surrounding WWII, and due in part to the rise of assimilation as a problem for Jews in America, the Orthodox movement as a whole began moving sharply to the right, and more and more centrist and Modern Orthodox Jews began feeling pressured to become more stringent and strict. Sixty or seventy years ago, Modern Orthodoxy was the dominant form of Orthodoxy in America: now it is barely hanging on, with a handful of synagogues in New York, Los Angeles, and a couple other places on the East Coast. Most Orthodox Jews are traditional, and often if not usually wear some variation on the black and whites. The difference is that non-Hasidic Orthodox Jews don't retain the old Polish styles, but simply wear black and white suits of a modern cut, and instead of the very wide-brimmed hats of the 19th century that Hasidim favor, they wear the fedoras common to New York gentlemen of the early 20th century, when most men wore hats, and most immigrants were coming through New York.

What is extremely amusing to me is that in Israel, many Sefardim and Mizrahim (Jews of Spanish or Middle Eastern ancestry), who have nothing whatsoever in their backgrounds to connect them to Eastern European interpretations of mussar, much less the folk customs of Hasidim (who all came from Eastern Europe), have now begun adopting the black and white suits as a way of marking their ultra-Orthodoxy. That cracks me up.

In any case, the side-locks of hair, called peyot, represent a particularly zealos interpretation of Leviticus 19:27 ("Do not shave a tonsure on your head, and do not obliterate the corners of your beard"). The reasoning is that it could be unclear what obliterate means: perhaps it means one should never, ever cut those hairs. Therefore, lest they mistakenly violate this commandment, they grow the hair at the temple (which is as close as one can come to having a corner of the beard) long; some never trim them, others only trim them after they reach a certain length. Some wrap them around the ears in various ways, some curl them, and some twist them in ways attributed to teachings from the mystical text Zohar. In fact, it appears that much of the popularity of growing payot to extra-long length seems to have originally derived from the popularization of the Zohar, and historically, most Jews probably did not wear peyot as we see them today. But today, they are universally recognized as a symbol of being ultra-Orthodox.

__________________
Dull sublunary lovers love,
Whose soul is sense, cannot admit
Absence, because it doth remove
That thing which elemented it.

(From "A Valediction: Forbidding Mourning" by John Donne)