In general, Karnatak music is characterized and structured by a great degree of precision and rigidity in framework and is based on a strictly organized system. The percentage of fixed compositions rendered by artists is also relatively high in Karnatak music...embellishments on fixed compositions is one of the prime elements of a Karnatak musical performance. Further in Karnatak system instrumental music very closely follows the vocal pattern.
"Romance of the Raga" (pp. 42-44)
In Karnatak music, a great deal of emphasis is also placed on the Sampurna (heptatonic) scale types, Melas as a means of classifying ragas [musical scales]....the 17th century text Chaturdanda Prakasikha lists out all the possible melas which could fit into the Karnatak system of music. This 72 Melakarata system still provides the basis for classification in the Karnatak music.Vijaya Moorthy