I am a Catholic, and I believe in both evolution and intelligent design, so I am not trying to doubt evolution, just understand it.
Why do humans have a 25 hour Circadian rhythm? You would think that after being on this planet for thousands of years, we would develop a shorter Circadian rhythm to coincide with the 24hr rotation of the Earth. Yet, our rhythm is closer to 25 hours.
A scientist tested this once by living underground for over six months. When she came out, she thought the date was, I believe, almost a month before the actual date (due to her losing an hour every day)
So what could explain this odd trait?
2007-02-16 08:38:11 · 8 answers · asked by Anonymous in Society & Culture ➔ Religion & Spirituality
Humans do not have a set 25 hour circadian rhythm. In a strict sense, circadian rhythms are endogenously generated, although they can be modulated by external cues such as sunlight and temperature. The rhythm is linked to the light-dark cycle. Animals kept in total darkness for extended periods eventually function with a "free-running" rhythm. Each "day," their sleep cycle is pushed back or forward (depending on whether the endogenous period is longer or shorter than 24 hours). The environmental cues that each day reset the rhythms are called Zeitgebers (German, literally "Time Givers"). Interestingly, totally blind subterranean mammals (e.g., blind mole rat Spalax sp.) are able to maintain their endogenous clock in absence of the external stimuli.
2007-02-16 08:54:07 · answer #1 · answered by ndmagicman 7 · 1⤊ 0⤋
It's simple: no organism's perfect. Evolution is based on survival of the organisms with the adaptations best suited for its own environment, not necessarily the best overall traits. The 25 hour Circadian rhythm probably would not significantly decrease the humans' fitness because humans are high in the food chain. Because of this, an extra hour of sleep won't lead to humans being eaten.
Besides, in the experiment, according to your account, the scientist lived underground. In a true human environment, humans can look at the sky to see if it's time to sleep. In the morning, the sun will wake up anyone who would otherwise sleep longer.
It's true that a 24 hour rhythm would probably be better, but a 25 hour rhythm is not harmful enough to cause major problems.
2007-02-17 19:07:28 · answer #2 · answered by x 5 · 0⤊ 0⤋
The first link talks about 24 hour rhythms, the second says "slight imperfections". Your scientist was in extreame conditions. Perhaps our natural cycle is re set by sunlight.
Even so, from an evolutionary point of view, just how crucial are they? Evolution isn't about achieving some form of perfection, but best fitting to an environment.
2007-02-16 16:52:40 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Our natural rhythm is longer than a day, but is reset by light.
2007-02-16 19:04:28 · answer #4 · answered by novangelis 7 · 0⤊ 0⤋
I'm sorry, you are going to have to cite some sources for this; it is news to me. We are pretty much tuned to the rhythm of our planet.
2007-02-16 16:43:57 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Wouldn't that be pro-evolution? I mean a perfect God wouldn't have messed that one up right? Evolution isn't about perfection, Intelligent Design is.
2007-02-16 16:43:44 · answer #6 · answered by Anonymous · 2⤊ 0⤋
Clint ! is that you buddy?
Wow, my Hero! (hero no. 2, that is)
Don't know.
Read about similar Experiment and they Went to Sleep Later and Woke up Later too.
Everything moved Forward, slowly.
Ditto.....................
2007-02-16 16:52:48 · answer #7 · answered by maguyver727 7 · 0⤊ 0⤋
That's an intelligent qusetion. But, sadly I don't have an answer!
2007-02-16 16:50:12 · answer #8 · answered by RealArsenalFan 4 · 0⤊ 2⤋