There is no easy way to determine when clothing was first developed, but some information has been inferred by studying lice. The body louse specifically lives in clothing, and diverge from head lice about 107,000 years ago, suggesting that clothing existed at that time.Another theory is that modern humans are the only survivors of several species of primates who may have worn clothes and that clothing may have been used as long ago as 650 thousand years ago. Other louse-based estimates put the introduction of clothing at around 42,000-72,000 BP.

Functions

The primary function of clothing is to improve the comfort of the wearer. In hot climates, clothing provides protection from sunburn or wind damage, while in cold climates its thermal insulation properties are generally more important. Shelter usually reduces the functional need for clothing. For example, coats, hats, gloves, and other superficial layers are normally removed when entering a warm home, particularly if one is residing or sleeping there. Similarly, clothing has seasonal and regional aspects, so that thinner materials and fewer layers of clothing are generally worn in warmer seasons and regions than in colder ones.

Clothing performs a range of social and cultural functions, such as individual, occupational and sexual differentiation, and social status.In many societies, norms about clothing reflect standards of modesty, religion, gender, and social status. Clothing may also function as a form of adornment and an expression of personal taste or style.

Clothing can and has in history been made from a very wide variety of materials. Materials have ranged from leather and furs, to woven materials, to elaborate and exotic natural and synthetic fabrics. Not all body coverings are regarded as clothing. Articles carried rather than worn (such as purses), worn on a single part of the body and easily removed (scarves), worn purely for adornment (jewelry), or those that serve a function other than protection (eyeglasses), are normally considered accessories rather than clothing,[citation needed] as are footwear and hats.

Clothing protects people against many things that might injure the uncovered human body. Clothes act as protection from the elements, including rain, snow and wind and other weather conditions, as well as from the sun. However, if clothing is too sheer, thin, small, tight, etc., the protection effect is minimized. Clothes also reduce the level of risk during activity, such as work or sport. Clothing at times is worn as protection from specific environmental hazards, such as insects, noxious chemicals, weapons, and contact with abrasive substances. Conversely, clothing may protect the environment from the clothing wearer, as with doctors wearing medical scrubs.

Humans have shown extreme inventiveness in devising clothing solutions to environmental hazards. Some examples include: space suits, air conditioned clothing, armor, diving suits, swimsuits, bee-keeper gear, motorcycle leathers, high-visibility clothing, and other pieces of protective clothing. Meanwhile, the distinction between clothing and protective equipment is not always clear-cut, since clothes designed to be fashionable often have protective value and clothes designed for function often consider fashion in their design.

The wearing of clothes also has social implications. They are worn to cover those parts of the body which social norms require to be covered, and act as a form of adornment, as well as other social purposes.

Source- http://en.wikipedia.org/wiki/Apparel