To sleep, perchance to dream....?

Nov 20, 2002
Wowie, looks like I started something here.... cool! :sun:

Being essentially on a kindergarten level re biology -- at least compared to most of y'all -- I'm grateful for all these fascinating responses.

Regarding the necessity of sleep: As Ob pointed out, sleep deprivation can indeed be lethal, so I agree that it must be more than just an ancient evolutionary quirk which persisted in more complex species. And I don't buy into the oft-repeated (on nature shows) theory that sleep is a mechanism to protect an individual from nocturnal predators.... aside from the fact that there are a whole lot of diurnal predators, being asleep would -- if anything -- make the individual more vulnerable to predators.

On the other hand, D's theory that sleep "allowed the body to be active internally to do all the housework where awake time used similar energies to mobilize the container" makes perfect sense to me, as does Ob's Ob-servation that "energy conservation has an evolutionary benefit as a trait".

As for dreaming -- as far as I know, at least in humans, it is also a necessity. One of the side effects of prolonged sleep deprivation is visual hallucinations, almost as if the "dreaming" mechanism suddenly breaks into the waking state after being suppressed for too long.

Which begs another question: Which came first, dreaming or sleeping? I really like Architeuthoceras' comment about dreaming being the equivalent of instinct.... subconsciously driving cephs and sea turtles (and TONMOers :smile:) to the appropriate spawning grounds at the appropriate time. An additional function of sleep could be to facilitate dreaming -- a vital way of processing information and memory -- since too much "daydreaming" would certainly interfere with an organism's other survival functions.

I was also unaware that cephs go through cycles which resemble sleep -- thanks to Robyn for that information. And thanks to Monty for the insight into possible parallels between ceph and human morphology. Monty, I like the idea of a combination of the second and third possibilities you listed.... i.e., that a primitive precursor to sleep existed in a common ancestor of cephs and humans, that it developed somewhat differently in both evolutionary lines, but that over the eons convergent evolution led to a function which appears similar in humans and cephs. (Does that make any sense? As a non-scientist, I'm having trouble expressing myself accurately.... :bonk:)

I think I have turned my own limited brain inside-out in an effort to understand all this complex information, but I'm enjoying the process immensely!

(who can vouch for the negative effects of sleep deprivation in online Scrabble players)


Pygmy Octopus
Dec 20, 2008
theories on sleep

a recent article i red(dont remember where) theorized sleep was actually a form a life practice, training us for situations that could arise. studies of an idian culture in south america showed that many dreams focused around a particually toxic insect in the area and rarely where as abstract as those we have. one theory on why we have such odd dreams at times is thought to be due to our broad range of daily experiences including movies and other highly imaginitive activities.

i was fascinated by this idea becuase, to me, it made alot of sense.. sleep maybe required in advanced organisms for physical reasons but mental as well..why cant that tiem be used as "practice" time for somethign dangerous we may have to react to in the future if the brain is capable of simulating that.

on the ceph side of things ive withnessed my octo twitching when sleeping.


Sep 23, 2009
I've been meaning to start keeping a "dream journal" near my bed at all times so that I can write down what I remember of my dreams as soon as I wake up, because I have some pretty whacked-out dreams. I've always thought of dreaming (from a layman's point of view) as an odd quirk of having a higher functioning brain, but sleep itself being a necessity with the purpose of repairing the works.

I've read in places that one of the functions of sleep is the reprocessing and storage of memories, so let me take a wild stab in the dark and suggest that maybe all animals that sleep have to dream, because maybe as a consequence of the brain going through all of these memories, it hashes some of them together and it "replays" through the mind? I'm thinking of this mechanism almost like when a computer hibernates: it has to dump the contents of the RAM onto a sector of the hard drive... maybe that's what our brains do when we dream, and during the transfer we re-experience these things.

Who knows. Well, probably a psychologist, and I'm certainly not one of those. I'm experiencing my own endeavor into sleep deprivation as I type this at almost 4am Chicago time. Very interesting things to twist our brains around...