What is obvious from that is the "connection" to the light reactions. The Calvin cycle needs NADPH and ATP from the light reactions. Thus the Calvin cycle is inseparable from the light reactions...they only occur in the light! This is why "dark reactions" is a poor name for the Calvin cycle. This relationship with the light reactions is reciprocal...the light reactions need a supply of ADP, Pi, and NADP+ which come directly from the Calvin cycle: