Why has nothing evolved to not need sleep?

[Delvo]

Sleep might not be possible to eliminate, but it can be and has been reduced. Giraffes do it less than two hours a day, sometimes not even half of one. So I wonder what makes the amount of it so different from one species to another.

 

[SteveGrenard]

www.sciencedaily.com/releases/2008/05/080513191934.htm

Wild Three-Toed Sloths Sleep 6 Hours Less Per Day Than Captive Sloths, First Electrophysical Recording Shows

ScienceDaily (May 14, 2008) — In the first experiment to record the electrophysiology of sleep in a wild animal, three-toed sloths carrying miniature electroencephalogram recorders slept 9.63 hours per day--6 hours less than captive sloths did, reports an international team of researchers working on the Smithsonian Tropical Research Institute's Barro Colorado Island in Panama.

"We are fascinated that some species sleep far longer than others. If we can determine the reasons for variations in sleep patterns, we will gain insight into the function of sleep in mammals, including humans," said first author Niels Rattenborg, group leader of the Sleep and Flight Group at the Max Planck Institute for Ornithology. "If animals behave differently in captivity (where all previous comparative studies were performed) than they do in the wild, measuring their brain activity in captivity can lead to the wrong conclusions."

Journal reference:

Niels C. Rattenborg, Bryson Voirin, Alexei L. Vyssotski, Roland W. Kays, Kamiel Spoelstra, Franz Kuemmeth, Wolfgang Heidrich, Martin Wikelski. 2008. Sleeping outside the box: electroencephalographic measures of sleep in sloths inhabiting a rainforest. Royal Society journal Biology Letters. doi:10.1098/rsbl.2008.0203

 

[SteveGrenard]

Not if you're a Eastern Hognose Snake.

(Ok, not exactly sleep)

This is known as thanatosis or playing dead. Possums do it, other animals do it including, no doubt, people who might find it advantageous to let their attackers think they're dead.

Where Hognosed snakes are concerned my personal theory is that it is the result of a seizure-like state. They are venomous rear-fanged species with both an eastern and western form.

This requires some explanation.

These snakes have evolved to eat Bufo toads. Bufo toad skin and parotid glands contain a digitalis like toxin. Digitalis slows down the heart rate. To combat this toxin the snake evolved larger than normal (for its size) adrenal glands: adrenal glands which hypersecrete epinephrine which counteracts digitalis. I believe that in a threat situation this hypersecretion of epinephrine is responsible for their initial reaction which is to rear up, spread its neck hood and then repeatedly "attack" their enemy. Curiously they do this with their mouth closed so they're not very serious about inflicting harm on their enemy and this has lead observers to comment that they're bluffing.

After this repetoire, with their excessive epinephrine exhausted, they literally poop out
(looks like playing dead), writhe, turn over, and twitch, even with their tongue hanging limply out of the mouth twitching. In a human having a seizure this exhaustion state is referred to as post-ictal. The initial display might be analogous to a seizure and the playing dead phase the equivalent of a post-ictal state of exhaustion.

So instead of fight or flight, these snakes fight and then play dead.

 

[Ichneumonwasp]

Some of you seem to have the history backwards.

Being always asleep was the original natural state of all life forms.
It is being awake, that is the evolutionary advantage. At least in the mobile ones.

Being awake, every now and then, allows mobile life forms to gather food, and conduct mating tasks. When survival does not require waking life, we are better off sleeping, according to nature.

Plants don't need a waking life, because they have adapted to meet all of their survival needs planted in one place.

I think that may depend on a more basic issue -- reception of environmental information. The hallmark of sleep is that environmental information is kept out of awareness. But, environmental information is always available to bacteria, plants, etc. That plants don't move is a function of the way they evolved and shouldn't really enter into discussions of quiescence or sleep, I think.

I agree with your point about focused awareness for movement, but it seems to me that reception of environmental info is a more basic issue. Sleep in mammals, for instance, is an active state neurologically.

 

[Capsid]

Some of you seem to have the history backwards.

Being always asleep was the original natural state of all life forms.
It is being awake, that is the evolutionary advantage. At least in the mobile ones.

Being awake, every now and then, allows mobile life forms to gather food, and conduct mating tasks. When survival does not require waking life, we are better off sleeping, according to nature.

Plants don't need a waking life, because they have adapted to meet all of their survival needs planted in one place.

As I said earlier, viruses/bacteria/fungi don't sleep. The original state is to reproduce and that means being "awake" whatever that means.

 

[Wowbagger]

I agree with your point about focused awareness for movement, but it seems to me that reception of environmental info is a more basic issue.

True. Animals need more enviornmental reception than plants, because they move around. And, they have been doing so long enough, that sensory organs could evolve in many of them, to help them make more effective use of their time awake.

 

[EHocking]

On the TV show Life on Earth it was reported that a certain species of bird spends all its adult life, except for nesting, on the wing. It didn't say they didn't sleep, but they do so in the air if they do at all.

The same thought came to me, Common Swift Apus apus is the bird you're thinking of. By all accounts they can remain aloft for years, only landing to nest and allegedly sleep on the wing. Whether that is a full deep sleep I can't find resources to support/deny or equivocate.

 

[SteveGrenard]

The same thought came to me, Common Swift Apus apus is the bird you're thinking of. By all accounts they can remain aloft for years, only landing to nest and allegedly sleep on the wing. Whether that is a full deep sleep I can't find resources to support/deny or equivocate.

Because without an EEG of this bird flying around for days, weeks, months, whatever, there is no way any scientist can say whether it is sleeping on the wing or not.

I posted a research study with a claim of the "first" study performed on a non-captive animal documenting sleep. It was the 3-toed sloth. Post#62.

 

[Ziggurat]

Plants don't need a waking life, because they have adapted to meet all of their survival needs planted in one place.

Both sleep and awake are neurological states, and they make no sense in the absence of a nervous system. Your statement is like saying that don't need to stand up, so they sit. Neither state describes them.

 

[SteveGrenard]

True. Animals need more enviornmental reception than plants, because they move around. And, they have been doing so long enough, that sensory organs could evolve in many of them, to help them make more effective use of their time awake.

Some plants, er, move around. Vines for example. Others send out shoots with roots and restablish themselves elsewhere. Plants also bend toward light and arrange their roots to maximize intake of water and soil nutrients. I have seen flowers go limp at night and perk up in the daylight. Some open and close their petals in response to external stimuli or time of day such as Venus Flytraps and Morning Glories. A case could be made that some plants demonstrate an extremely primitive sort of pre-cursor to a nervous system. Now if we could find out if opium poppies never feel pain ...

Feed me Seymour, Feed me:

 

[not_so_new]

As some have already said, who's to say that evolution didn't try "no sleep" and tossed it out on the heap of failed traits? That may have happened many times in the past.

Insomnia can be found in other animals (well not technical "insomnia" but lower sleep levels than others of the same species). Anyway, because it can be found in the wild but is not prevalent leads us to the conclusion that...

1) It is a trait that has had the opportunity to advance if it were viable.

2) Because it has had the opportunity and did not flourish it is not viable for many of the reasons stated by others on this thread.

 

[schlitt]

You guys are just plain mean! giving Zeuzzz logic and facts, when all he really wanted was the following:

Zeuzzz you are right! My goodness! Why has no one thought of this before? If evolution was true it would make all creatures not need sleep! Conclusive evidence against evolution!

Congratulations Zeuzzz you have just proved 97% of biologists wrong, and therefore proved your particular brand of religion correct by way of "either or fallacy". Good for you!

 

[EHocking]

Because without an EEG of this bird flying around for days, weeks, months, whatever, there is no way any scientist can say whether it is sleeping on the wing or not.

Thus my equivocation. Practically all resources I found repeat the claim as "as any fule kno", but, being a fan of urban legends as well as being a naturally curious sceptic, I'm having to take the claim with a grain of salt. OK, arguing from ignorance is not a pretty trait, but how does a bird maintain controlled, directional (in a nav sense) flight when asleep. Littl "nod offs" I can see, but prolonged sleep of even a few minutes in my mind could cause great problems for a Swift, even if cruising at 10,000 ft+

I posted a research study with a claim of the "first" study performed on a non-captive animal documenting sleep.

I'm mobile this weekend, so must have missed that post.

It was the 3-toed sloth. Post#62.

Hard to tell with them...

(yes, I know, UL re:sloths are also exaggerated.)

 

[Wowbagger]

Some plants, er, move around.

Pardon me for oversimplifing the point. most animals move around a lot more than most plants. So, the survival strategy of animals eventually involved sensory perception, and waking awareness. Although plants do move, it isn't very much, and least not so much that they would develop senses and awareness, as part of their survival strategy.

 

[Zeuzzz]

On the TV show Life on Earth it was reported that a certain species of bird spends all its adult life, except for nesting, on the wing. It didn't say they didn't sleep, but they do so in the air if they do at all.

Albatross maybe?

Thats a good point, sleep swimming is one thing, but sleep flying is quite another

 

[Zeuzzz]

You misquoted me - you moved my response to make it look like it was responding to something else - and then tried to mock me for your own lie. This was obviously intentional, since you must have done it by hand and made a point of ridiculing your (false) version of my response.

Misquoting is

a) unethical
b) really, really stupid, since the original post is right there, and
c) probably a violation of the forum rules.

....or d) a mistake. Its kinda hard to get the quotes right when your stacking three quotes inside of one another. Appologies

Anyway, what did you mean then? This one should be correct.

It makes extremely good evolutionary sense to sleep: You are safe

If they didn't need sleep, they wouldn't need to do these things, and could spend more time feeding and being aware of predators. Surely?

That's been addressed by nearly every post in this thread. Are you sleep-posting?

Why the accusation of sleep posting? On forums people tend to discuss the subject of the thread, one persons answer does not render the rest of the thread worthless, people have opinions and discussions about their opinions. I dont see why you had to say this.

Besides, if you had been paying attention to what is being said in this thread, its obvious that if I had been sleep posting I would have been at a major disadvantage, and probably been eaten by a predator by now. Silly.

 

[Zeuzzz]

I'm not sold on the "sleeping is safe" idea. Hiding and keeping quiet can enhance safety, but sleeping adds nothing to the situation. Awake and alert works best every time. You can always play possum if you're awake, but how do you play alert if you're asleep?

My point exactly. People seem to be confusing the disadvantage of sleeping and not being aware of your surroundings with the proposed reasons why animals sleep. Thats why I queried why no animals seem to have evolved to get rid of this disadvantage of not being aware, and perform the various reasons for sleeping while not having the disadvantage of being not alert and aware. Which seems to not have happened. Dolphins and whales come pretty close, but they still sleep and reduce awareness, just in a different way. As you say, awake and alert works best every time.

If an animal could have evolved to perform the job sleep does (whatever you consider that to be, saving energy, sorting out memory, maintenance on the body, etc) it would be at a huge advantage. It would be alert 24/7. This has not happened. So, the aspect of sleep that requires a non conscious component seems to be very important throughout the entire animal kingdom. Which I just find interestng, as no-one seems to have a conclusive reason for why this altered state of consiousness is needed, but it seems very important in every animal.

 

[Zeuzzz]

You guys are just plain mean! giving Zeuzzz logic and facts, when all he really wanted was the following:

Zeuzzz you are right! My goodness! Why has no one thought of this before? If evolution was true it would make all creatures not need sleep! Conclusive evidence against evolution!

Congratulations Zeuzzz you have just proved 97% of biologists wrong, and therefore proved your particular brand of religion correct by way of "either or fallacy". Good for you!

What an odd post. This thread is about the way that sleep has evolved within darwins evolution, and the advantages and disadvantages of it. I certainly wasn't trying to have a poke at evolution.

You should be careful, sarcasm is lost on some, people may think your actually a creationist, or perhaps even worse, your one of those people that think that evolution is just a theory, and so by default God must exist Whatever the hell 'god' means.

As I said on the last page, incase you missed it: It's possible that such a mutation to reduce sleep and increase the percentage of the day animals are awake and aware by performing the job of sleep while fully conscious HAS occurred, and turned out to NOT be adaptive, in which case it quickly disappeared from the gene pool again. The reson why this was not an advantage and died out is the underlying question.

 

[Zeuzzz]

Some of you seem to have the history backwards.

Being always asleep was the original natural state of all life forms.
It is being awake, that is the evolutionary advantage. At least in the mobile ones.

Being awake, every now and then, allows mobile life forms to gather food, and conduct mating tasks.

This should mean that over a very, very long period of time animlas are evolving to sleep less, correct? I mean, there are numerous advantages of being awake, so over time animlas that sleep less and have evolved to perform the job sleep does while awake should live longer. Survival of the fittest, etc.

I personally dont think this is happening. Maybe in some species to a small extent, but none seem to have been able to negate sleep and be able to do what it does in an awake and alert state. But I dont have a clue why. This is what puzzles me.

 

[Wowbagger]

This should mean that over a very, very long period of time animlas are evolving to sleep less, correct? I mean, there are numerous advantages of being awake, so over time animlas that sleep less and have evolved to perform the job sleep does while awake should live longer.

Not necessarily! There would also be survival advantages for gazelles to run at over 200 mph. But, that is unlikely to happen (their current speed is around 50 mph).

There are constraints on perfection: How far an animal can run and how long it can stay awake, needs to be balanced by the reality of what they can physically achieve, given: historical constraint, regulation of energy, laws of physics, etc.

There are also survival advantages to sleeping a certain amount: downtime is necessary to regulate energy expenditure, and bodily repair, etc. This has to be balanced against the time spent awake, and it makes sense that an optimal ratio of sleep/wake-time would be worked out, for each species.

And, I am sure it does change over time: Sometimes animals will sleep more often, when selection pressures make them think they can afford it. And, sometimes animals will remain awake, more often, when selection pressures placed on them forces them to.