Gotta love that watchmaker analogy. Turns out the human circadian (sleep-wake) rhythm is a little bit over 24 hours long—more like 24:11, so your body is always pushing you to go to sleep 11 minutes later every day. (Thankfully it tends to synchronize with light and darkness, so it doesn’t get too far off schedule.) That’s some nice watchmaking there, God.
Is that 24:11 a literal figure for every single person, or is it just an average, over a a group of individuals?
Since the day/night cycles vary all around the planet, it would make far more sense, from a design standpoint, to worry more about the synchronization mechanism, than to get the exact sleep-wake rhythm correct.
It isn’t literally that for every single person, but assuming you don’t have a mutation in your chronobiological genes it is pretty close to that.
People with mutations in various regulatory genes end up with significantly different sleep-wake cycles. The reason that our bodies reset ourselves under sunlight is probably to help correct for our clocks being “off” by a bit; indeed, it is probably very difficult to hit exactly 24 hours via evolution. But 24:11 plus correction lets it be off by a bit without causing a problem.
Good enough is probably better than perfect in this case, both because it means that mutations to the clock are less deleterious (thus those who have mutated clock genes are more likely to survive if they have said adjustment capability, meaning that the adjustment gene is even more strongly selected for) and because it means that we can travel and adjust to new time zones. For most creatures, this doesn’t matter, but for creatures which travel long distances, this is a real advantage for staying on the proper day/night cycle.
Gotta love that watchmaker analogy. Turns out the human circadian (sleep-wake) rhythm is a little bit over 24 hours long—more like 24:11, so your body is always pushing you to go to sleep 11 minutes later every day. (Thankfully it tends to synchronize with light and darkness, so it doesn’t get too far off schedule.) That’s some nice watchmaking there, God.
Is that 24:11 a literal figure for every single person, or is it just an average, over a a group of individuals?
Since the day/night cycles vary all around the planet, it would make far more sense, from a design standpoint, to worry more about the synchronization mechanism, than to get the exact sleep-wake rhythm correct.
It isn’t literally that for every single person, but assuming you don’t have a mutation in your chronobiological genes it is pretty close to that.
People with mutations in various regulatory genes end up with significantly different sleep-wake cycles. The reason that our bodies reset ourselves under sunlight is probably to help correct for our clocks being “off” by a bit; indeed, it is probably very difficult to hit exactly 24 hours via evolution. But 24:11 plus correction lets it be off by a bit without causing a problem.
Good enough is probably better than perfect in this case, both because it means that mutations to the clock are less deleterious (thus those who have mutated clock genes are more likely to survive if they have said adjustment capability, meaning that the adjustment gene is even more strongly selected for) and because it means that we can travel and adjust to new time zones. For most creatures, this doesn’t matter, but for creatures which travel long distances, this is a real advantage for staying on the proper day/night cycle.