"Fordism": An Example
If you think about a car, for example, it's production involves a few, highly-technical, skilled, elements (such as engine assembly) and a multitude of non-technical, low-skill, elements (such as tightening the bolts that hold the wheels to the chassis).
Ford reasoned that to pay a single person to produce a whole car was
economically inefficient because you would have to employ a highly-skilled
worker (to understand and complete the technical assembly) who would also be
employed to complete the many low-skill tasks involved. In effect, you
would be paying a highly-skilled specialist a high wage
when the majority of their work tasks were basically very low-skilled;
it made more economic sense, therefore, to employ different people
to complete different tasks.
In this way, a small number of (expensive) skilled workers could be employed alongside a large number of (cheaper) unskilled / semi-skilled workers. Ford proudly boasted that his factories were able to employ both able-bodied and disabled workers (men with one arm, for example). The development of the constantly-moving production line simply represented an efficient method of organising this particular process.
Ford was not the first person to visualise a complex division of labour. In the 19th century, Charles Babbage, for example, had eloquently described just such a process for the manufacture of pins (don't ask…). Ford, however, was probably the first manufacturer to apply these principles to development of modern forms of mass production.