The Naked Scientists

The Naked Scientists Forum

Author Topic: Is sleep evolutionarily disadvantageous?  (Read 4932 times)

Offline DERYN

  • Jr. Member
  • **
  • Posts: 25
    • View Profile
Is sleep evolutionarily disadvantageous?
« on: 20/12/2010 11:09:44 »
Hi everyone,

I have often thought that in terms of self preservation, staying alive, sleep is one of the most vulnerable positions we could find ourselves in. It seems to me, any creature, including man, has had to develop ways of avoiding being injured, killed, and eaten by predators. Surely being asleep, dead to the world, would put any creature in danger of being killed? Is sleep absolutely necessary and wouldn't the development/evolution of a non sleeping human be more beneficial? Surely sleeping Neanderthals were easy pickings for the creatures of the night?

Deryn 
« Last Edit: 20/12/2010 22:54:44 by chris »


 

SteveFish

  • Guest
Re: Is sleep evolutionarily disadvantageous?
« Reply #1 on: 20/12/2010 16:02:03 »
The fact that sleep appears to be necessary, especially for all animals with the most highly developed brains, suggests that sleep provides some very basic function that can't be eliminated or replaced by evolutionary mechanisms. In other words, in terms of reproductive success, lack of sleep is more detrimental than the danger it incurs. Also, don't forget protective mechanisms that allow safe sleep. Neanderthals were smart and had a social structure so they, for example, could find or make a safe place and set up a guard. Other animals have, sort of, automated interrupts (like a computer program) that awaken them very quickly. Herd animals have the herd, which is evolutionarily designed to sacrifice a few for the many.
 

Offline DERYN

  • Jr. Member
  • **
  • Posts: 25
    • View Profile
Re: Is sleep evolutionarily disadvantageous?
« Reply #2 on: 20/12/2010 17:36:33 »
Thanks Steve,  if it wasn't necessary we wouldn't have to sleep is what you are saying ?

But I am still a little unsure why we have to sleep in such a way ? By that I mean, when we are in a deep sleep we are practically unconscious. I say 'practically' because I think of being under anesthetic, or receiving a blow to the head as fully unconscious. ( is there a measurable difference ? )When we are asleep we are not conscious at all about where we are at that particular moment. Even when we awake we still need to ask ourselves 'where am I' ? We have no control over our muscles or movements. We have no way of communicating with others. 'Dead to the world' is a common phrase.

So we have to go into this unconscious state at least once every 24hrs ? Why ? What are the most common reasons ?

I know from experience like everyone else that if we don't get this sleep we suffer from fatigue,we get overly tired. This in itself is a good enough reason as in such a state we can come to all sorts of harm.

Our bodies take on quite a few knocks over the space of a day and perhaps sleep provides the body with a time to heal itself ?

Those are 2 reasons I can think of for why our bodies might need rest and recuperation.( are there more reasons ? ) But do we really have to be rendered unconscious ? Evidently so is the answer.

Any other views ?

Deryn

 

SteveFish

  • Guest
Re: Is sleep evolutionarily disadvantageous?
« Reply #3 on: 20/12/2010 18:41:23 »
I don't think that sleep research has been able to come up with a well supported theory of what sleep actually does for us. There is quite a bit known about what brain subsystems are doing in the different stages of sleep. Most theories I have heard suggest that sleep is a period during which different parts of the brain process information for general maintenance of the giant biological computer we have in our head. Such suggested processes include memory consolidation and shuffling of information into categories for easier retrieval and good cognition. The brain is very plastic, in that, neural connections are continuously made, unmade, strengthened, and weakened. Also, neurons are completely eliminated in a process of brain development throughout life, although this is most active very early in development. For these processes to be accomplished correctly the brain may have to be in a special state.

Regarding your concern about complete unconsciousness, I think one can program themselves to awaken abruptly to specific stimuli. I know that when I have set my alarm clock for something important I will often awake just before the alarm goes off. I always assumed there was some little noise the clock made before turning on the alarm. Also, if you know a soldier who lived for some period in a war zone, or an emergency worker that has to be on call, or just a mom during the early period with babies that need to be fed at night, ask them how they slept and what did and didn't awaken them. This might be interesting. Steve
« Last Edit: 20/12/2010 18:44:03 by SteveFish »
 

Offline maffsolo

  • Sr. Member
  • ****
  • Posts: 280
    • View Profile
Re: Is sleep evolutionarily disadvantageous?
« Reply #4 on: 20/12/2010 22:06:21 »
Kine instinct is not well inherited by man, they are a more or less a conditioning.
Woman have the maternal instincts built in and coded, some may say they all don't but it might be that they chose to ignore them.

Maybe survival, this is what may have inspired night watches and timed shifts.
« Last Edit: 20/12/2010 22:13:58 by maffsolo »
 

Offline Don_1

  • Neilep Level Member
  • ******
  • Posts: 6890
  • Thanked: 7 times
  • A stupid comment for every occasion.
    • View Profile
    • Knight Light Haulage
Is sleep evolutionarily disadvantageous?
« Reply #5 on: 21/12/2010 08:51:05 »
This just my personal view.

Most animals do not sleep quite so deep as humans. Even some humans, in more vulnerable circumstances, probably manage to sleep with 'one eye open', so to speak. But for those of us who live in the highly sociable civilisations, the threat of predators has long been eradicated by our way of life, which may have allowed us, over a long period, to sleep better than we would otherwise have done. Returned to a more precarious lifestyle, living on open savanna's or in dense forest, we might find ourselves in considerable trouble, but after a few generations, might revert to lighter sleep periods which would help protect us from predators.

What I am suggesting here, is that humans have unwittingly self trained themselves to a single long, deep overnight sleep, rather than the shorter, lighter and more frequent naps which other animals, in far more precarious circumstances, will take.
 

Offline Bored chemist

  • Neilep Level Member
  • ******
  • Posts: 8659
  • Thanked: 42 times
    • View Profile
Is sleep evolutionarily disadvantageous?
« Reply #6 on: 21/12/2010 16:17:26 »
I heard an interesting theory once. Sleep is to give the body something to do when it's dark.
Otherwise we would be wandering about in the dark and would hurt ourselves.


It also gives an opportunity for repairing damage and sorting out the memories.
 

Offline DERYN

  • Jr. Member
  • **
  • Posts: 25
    • View Profile
Is sleep evolutionarily disadvantageous?
« Reply #7 on: 21/12/2010 19:50:20 »
I'm guessing that during our early evolution, more or less out in the open air, or perhaps in the luxury of a nice cave, we probably took short naps and faded in and out of sleep while being roused by animal sounds and other commotions. And living in small groups there was probably sentries posted.

I think that sleep probably wasn't confined to just night times either. I could imagine a group hunting in small groups using up large amounts of energy followed by a good feed, and then like now, maybe a snooze while food was digesting. In such a situation the strongest probably fed and slept while the weaker ones in the group busied themselves on scraps ?

But as hunters became more proficient at hunting and finding food and ways of storing food was discovered, then perhaps the beginnings of more leisure time once the sun went down resulted in a work by day sleep by night routine ?

Of course we have the luxury of nice warm beds to retire to now and so the whole idea of sleep has become something humans spend almost half of their lives doing as part of their recreational non work time. Longer sleeping patterns have no doubt developed as a consequence. The ability to sleep 'with one eye open' has also become more difficult as a consequence. Not impossible, but difficult I would say.

Deryn

 

Offline CliffordK

  • Neilep Level Member
  • ******
  • Posts: 6321
  • Thanked: 3 times
  • Site Moderator
    • View Profile
Is sleep evolutionarily disadvantageous?
« Reply #8 on: 22/12/2010 10:42:13 »
Keep in mind that sleep is an evolutionary adaptation much older than humans. 

Some animals have evolved to hunt and forage during the day.  Some at night.

While technically an animal could be active both during the day and night, it seems that most have adapted to either daytime or nighttime activities. 

Thus, a period of hunting for a "safe" place, and relative inactivity can be considered a protective mechanism.  Using very little energy.  Minimal movement, thus less likely to be seen or attract attention.  For large animals, less likelihood to break a leg or otherwise get hurt.

The regenerative nature of sleep and the ability to better fix memories with sleep would have evolved in parallel to the other needs for safe inactivity & energy conservation cycles.
 

Offline grizelda

  • Hero Member
  • *****
  • Posts: 740
    • View Profile
Is sleep evolutionarily disadvantageous?
« Reply #9 on: 05/01/2011 02:04:34 »
One theory that might fit is that the mind regenerates each night, like a crystal or hologram, so all sources of psychic noise must be squelched so as not to ruin the copy process, which also integrates new content. Disturbances of this process might be responsible for memories losing accuracy over time.
 

The Naked Scientists Forum

Is sleep evolutionarily disadvantageous?
« Reply #9 on: 05/01/2011 02:04:34 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums