Complex sentence: The defining principle that Pittendrigh developed throughout his career was that the properties of the circadian clock is independent from those of the behaviors it controlled, which gave him the freedom of studying the clock through a range of physiological functions from Drosophila hatching to rodents locomotor activities.
Split into simpler sentences: The defining principle that Pittendrigh developed throughout his career was that the properties of the circadian clock is independent from those of the behaviors it controlled. This gave him the freedom of studying the clock through a range of physiological functions from Drosophila hatching to rodents locomotor activities.