If we define larks as those whose circadian cycle leads the day-night cycle, and owls as those whose circadian cycle lags the day-night cycle, it's easy to hypo

If we define larks as those whose circadian cycle leads the day-night cycle, and owls as those whose circadian cycle lags the day-night cycle, it's easy to hypothesize reasons for lark dominance in the civic schedule. Hypothetically, say local sunrise is 6 AM, and sunset 6 PM, a lark rises at 5 AM and retires at 9 PM, and an owl rises at 7 AM and retires at 11 PM. If the lark wishes to be immediately productive on waking, they might generate noise, vibration, or odors in the owl's sleeping area, or may simply resent the owl for continuing to sleep while the lark has started working, and thus may wake the owl intentionally. If they have a task that requires cooperation, they could either wait 2 hours for the owl to wake, or go rouse them immediately. At that point, the owl has had 6 hours of sleep, and could probably function on that amount for that day. The owl, on the other hand, can work cooperative tasks immediately on waking, as the lark is already awake, and has no reason to ever awaken the lark prior to the natural conclusion of their sleep cycle. The converse act to the lark waking the owl 2 hours early is the owl keeping the lark up 2 hours late, after which the lark will likely just wake later. Each has a 2 hour sleep deficit, but the owl would have been re-clocked by daylight all day, and thus it would be more difficult for them to retire early after being awakened early (unless the weather was gloomy and overcast). They would also desire to awaken 2 hours later than usual the next morning. But there the lark is again, waking the owl up early again. The lark can cause the owl to be chronically sleep deprived, and the owl cannot effectively retaliate. So the owl can, at best, create rules that prohibit larks from disturbing others' sleep before "a reasonable hour". Commuting, artificial lighting, time zones, and daylight savings have all combined to make that "reasonable hour" less reasonable. Daylight savings is a particularly execrable lark tradition. While the owl is sleeping, the lark changes all the clocks, and then wakes up the owl, waving the clock in their face, so the owl does not murder the lark immediately. And then the larks only relent when the evidence of the sunrise would reveal the ruse. Only the larks have any real incentive to redefine civil time to get the owls out of bed earlier. So when someone says, "your body-clock is messed up," the best response is, "your civil time is messed up," and then roll over for a few more zees.