Why has nothing evolved to not need sleep?

Zeuzzz said:
....or d) a mistake. Its kinda hard to get the quotes right when your stacking three quotes inside of one another. Appologies :o
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Not accepted. You misquoted me and then ridiculed your own distorted version of my post. I fail to see how that could be a "mistake".

Why the accusation of sleep posting?
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There were many posts explaining the answer to that. As usual with you, you ignored them. There are several giving specific counterexamples to some of your claims (that no animals evolved to perform the "jobs that sleep does" while awake, for example). You ignored those as well.

My own summary is that the whole question is nonsensical. You might as well ask why living things are ever awake. The answer is that they evolved that way because it allowed them to occupy a niche.
 
Polgara said:
Well, is it random or is it not? Prove the random. :jaw-dropp
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It's neither. It's a very complex process that cannot be correctly characterized by pithy statements like "evolution is random" or "evolution is not random". Please, please, please don't start a discussion over that - if you must, first go read the thread with that title.

EDIT - or this one, which is even worse.
 
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sol invictus said:
Not accepted. You misquoted me and then ridiculed your own distorted version of my post. I fail to see how that could be a "mistake".
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Well, what can I say? I would appologise again, but you wouldn't accept that again I presume. You'll just have to keep sulking about what happened.

There were many posts explaining the answer to that. As usual with you, you ignored them. There are several giving specific counterexamples to some of your claims (that no animals evolved to perform the "jobs that sleep does" while awake, for example). You ignored those as well.
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I think your just being overtly pedantic. You just presume that I ignore something and stick to my original position. Its yet another classic case of you telling people what my position is. What you think my position is is quite different to my actual position. You should just ask me what my position is instead of jumping to erroneous conclusions. I have in fact asked questions throughout this thread, hoping to learn something that I didn't know the answer to. You do know what a question mark means? Dont you????

The statement I posted was this: 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?

Are you disputing that being aware of your surroundings is an advantage to being asleep and completely ignorant of them?

My own summary is that the whole question is nonsensical. You might as well ask why living things are ever awake. The answer is that they evolved that way because it allowed them to occupy a niche.
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Totally unrelated comparison.

Most other people seemed to find it an interesting question, and are continuing a resonable dialogue. You just want an argument. Maybe you know conclusively why all animals sleep? Even experts in this field dont claim they know this. So please, if you know, enlighten us all.
 
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Zeuzzz said:
What you think my position is is quite different to my actual position. You should just ask me what my position is instead of jumping to erroneous conclusions.
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I didn't assume anything - your position was clearly stated in your question. You cannot ask a question like "why are forum posters with mis-spelled Greek deities as their monikers always wrong, while those with Roman deities usually correct?" and then claim you didn't take the position implied by the question.

Are you disputing that being aware of your surroundings is an advantage to being asleep and completely ignorant of them?
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Yes, of course I am, because it's obviously not true (at least if by "advantage" you mean "genetic or evolutionary advantage"). How many plants are awake? How much of the biomass on earth consists of plants?

You see, thinking isn't really that hard (for non-vegetables, that is).

Totally unrelated comparison.
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The converse of your question is a "totally unrelated comparison"?
 
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sol invictus said:
It's neither. It's a very complex process that cannot be correctly characterized by pithy statements like "evolution is random" or "evolution is not random". Please, please, please don't start a discussion over that - if you must, first go read the thread with that title.

EDIT - or this one, which is even worse.
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Agreed, it's not a simple or pithy statement. That's why I had to point it out. But, I'll let if go. I'm feeling groovy. heh
 
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sol invictus said:
I didn't assume anything - your position was clearly stated in you question. You cannot ask a question like "why are forum posters with mis-spelled Greek deities as their monikers always wrong, while those with Roman deities usually correct?" and then claim you didn't take the position implied by the question.
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And my position was changed later when someone informed me of situations when this was not true. Infact it was you that linked to the info about dolphins yourself. You just presumed that I hadn't changed my original position. Its called learning.

You do still learn new things sometimes, dont you Sol? Or do you know it all already?

Yes, of course I am, because it's obviously not true (at least if by "advantage" you mean "genetic or evolutionary advantage"). How many plants are awake? How much of the biomass on earth consists of plants?
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So plants are animals now eh? :rolleyes:

It was a genreal statement, of course there are counter exaples for specific cases. It depends on your definition of what sleep is.

So it may be a good idea to try to define sleep, as no-one seems to be 100% sure, and to avoid idiots like you jumping on every sentence I write and just claiming everything I say is wrong.

So, from what people have said in this thread so far, the impression I get is:

Sleep is not:

* rest
* torpor
* coma
* merely immobility

Sleep is:

* A lack of/decrease in awareness of environmental stimuli
* Easily reversible (to wakefulness)
* Has distinct EEG patterns

However, sleep is different in all animals. Fish and Amphibians show periods of activity and inactivity and show less response to environmental stimuli in 'quiet' times. Reptiles EEG's are distinctly different from wake, and show similar sleep signs to mammals. Birds EEG has distinct sleep stages, and may even enter certain types of sleep while flying. Insects sleep, based more on behavioral criteria, no EEG recordings.

So: 1) All animals show consolidated periods of activity and inactivity 2) All show basic rest-activity cycle (ultradian rhythm), including single-celled organisms 3) However, not all animals show true sleep (defined by mammalian sleep)


What I'm asking, in an indirect way, is why do animals have to shut themselves off from the rest of the world at all. I can see all the advantages of sleep, but not why you have to become unconsious (rather alter your state of consciousness) to achieve these. I dont see why the part of sleep where you become not aware of your surroundings is a neccissary component. This apsect only serves as a disadvantage.
 
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BenBurch said:
We find that some types artificial neural networks require a "sleep" phase to normalize their memories. It might be an artifact of that mode of processing.
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That's really intriguing. Can you recommend any relatively accessible write up about that?
 
Zeuzzz said:
Thats a good question actually, do single-celled organisms and simpler multi-celled organisms rest? at what point along the complexity chain does the need for sleep and rest begin?
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I'm not so sure "rest" is the same thing as "sleep". If you differentiate the two, then certainly only species with relatively advanced nervous systems (a brain, at least) could be said to sleep.
 
Zeuzzz said:
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.
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To find the reason for sleep stand outside for 24 hours and note the pattern of light and dark. Most chemical reactions act faster with more energy.
 
As many people have pointed out sleep is a good way to conserve energy and is actually safe in comparison to going out looking for food.

The other thing that comes into play is that it makes sense to only be active part of the day. It would be expensive to evolve separate systems for night and day operation, specialization for gathering resources at a particular time is simply easier. Like all evolutionary processes once the trait exists, other traits will evolve to make use of it, making it effectively essential. I.E. since sleep existed already, it got tagged as the perfect time to process the days information.

If you were going to look for animals that don’t sleep I suggest they would be found in conditions where conditions are nearly identical most of the time. Caves, deep water, etc. Even then, if their ancestors lived elsewhere they may have evolved traits that depend on sleep.
 
Zeuzzz said:
Are you disputing that being aware of your surroundings is an advantage to being asleep and completely ignorant of them?
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Most animals and indeed many people are very light sleepers. With only a few exceptions a moving predator makes enough noise to wake most prey animals. Sleep, is also a near perfect defense against ambush predators that don’t move much.

I bowhunt deer occasionally and can guarantee you it’s much easier to catch them of guard when they are out looking for food then it is to find and sneak up on them in their sleep. So, not only is sleep a good energy conservations strategy, looking for sleeping animals is not a good predator strategy, making sleep even safer.

Being aware costs effort and energy, it only makes sense to expend that energy only when it’s absolutely needed. Finding alternative strategies which use less energy whenever possible seems like a very logical outcome to me.
 
godless dave said:
It is both and neither, depending on how you define "random", which is a pretty difficult concept to begin with.
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Apoplectic Sol (I think it was Sol) begged mercy on not discussintg the topic. I acquiesced.

However, -evil grin, I made no mention of not speaking upon random or chaos theory.

I personally believe there is order in everything. Random just indicates that we haven't been able to see, or establish, order in certain equations and patterns.
 
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