Are there brainless creatures that don't sleep?

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In summary: The prefrontal cortex (PFC), which helps manage emotions, cognition, and behavior, becomes less active during wakefulness. It becomes more active during delta sleep, which is when our dreams occur.In summary, the cells in the heart keep beating throughout your life. It doesn't sleep. So why is it not similar in the brain?The cells in the heart keep beating throughout your life. It doesn't sleep. So why is it not similar in the brain?The cells in the heart keep beating throughout your life. It doesn't sleep. So why is it not similar in the brain?The cells in the heart keep beating throughout your life. It doesn't sleep
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Cobul
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The cells in the heart keep beating throughout your life. It doesn't sleep. So why is it not similar in the brain?

Are there any brainless creatures like the heart that don't sleep?
 
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The heart is not a "creature", it is an organ in a living creature.

Bacteria are "creatures", and brainless, and don't sleep.
 
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Also, OP gives the impression that he/she believes the brain shuts off when creatures sleep. There is not much to work with here. We need a better question.
 
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  • #4
Cobul said:
The cells in the heart keep beating throughout your life. It doesn't sleep. So why is it not similar in the brain?

Are there any brainless creatures like the heart that don't sleep?
Haborix said:
Also, OP gives the impression that he/she believes the brain shuts off when creatures sleep. There is not much to work with here. We need a better question.
Agreed; @Cobul; if the heart in a human doesn't stop, then why do you think the human brain "sleeps"? Or, what does one thing have to do with the other? Do you know what sleep is?
 
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  • #5
This thread started out in a way that precludes getting good answers.

There are simple single cell marine organisms like dinoflagellates, tenefors, and many other simple terrestrial beasties that are diurnal, nocturnal, or crepuscular (twilight). They are adapted to be busy feeding (or whatever) during the time of day when they have best chance of success. And not get eaten, for example. At other times of the day/night cycle they go deep into the sea, or hide out on the bottom. Out of harm's way.

The early organisms set the useful trait into action: responding to various natural cycles is very adaptive.

You cannot use human biology as an example of all of the daily, lunar, and seasonal cycles that plants and animals display. Humans have some few of these traits but not all. We evolved long after these cycles had worked just fine for trillions of organisms over eons. We still respond to them today.

For example: Human vision works best in the day. We have genes to set our daily clocks.

Humans originally found shelter during the night and slept to avoid becoming lion chow. Sleeping is a good way to do some routine biochemical chores, if you sleep in safe place. It also keeps us out of trouble. Because on moonless nights our eyes are no match for large nocturnal predators night vision. So wandering around blindly at night is not adaptive and is strongly selected against. An electrified world has messed this up somewhat. There are diseases related to day/night cycle disruption - NIH has of papers on the subject of what psychiatrists call 'Diurnal rhythms'.

This is a huge subject. Circadian (daily) rhythms are one part of it. This link is meant for non-biologists:
Try: https://www.nigms.nih.gov/education/fact-sheets/Pages/circadian-rhythms.aspx

Photoperiodism (day length), another cycle type, is tied to seasonal day length.
https://en.wikipedia.org/wiki/Photoperiodism -- Common in animal and plant species.

There are others, example -- lunar cycles or tidal cycles.
 
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russ_watters said:
Agreed; @Cobul; if the heart in a human doesn't stop, then why do you think the human brain "sleeps"? Or, what does one thing have to do with the other? Do you know what sleep is?

That's a good point. So the better question would be why do we have to sleep at night and why do insects also sleep when the cells can keep functioning like the heart. So in theory we should be able to be sleepless. What vital functions do sleep serve? I once read a whole book why we sleep and at the end of it it was still a mystery why we and living things sleep. The book was a decade old. So is there definite answers now?

(this was written before reading Jim message)
 
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Cobul said:
That's a good point. So the better question would be why do we have to sleep at night and why do insects also sleep when the cells can keep functioning like the heart. So in theory we should be able to be sleepless. What vital functions do sleep serve? I once read a whole book why we sleep and at the end of it it was still a mystery why we and living things sleep. The book was a decade old. So is there definite answers now?
Some parts of our brain stay active when we sleep, which keeps us alive. Have you googled "why do humans sleep"? The specifics aren't known for sure, but there is a lot of general information out there.
 
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@russ_watters - two clear reasons why humans sleep, there very likely are others:
1. Primate brains generate tau proteins and other biochemical "waste" when awake that can only be removed during long-wave (or delta) sleep. Failure to do this results in a build up which eventually leads to various dementias, plus other CNS problems. This is found primates

2. Night vision in humans, um, stinks. When compared with lions, leopards, and other predators, human night vision comes as a distant third. Wandering around virtually blind on a moonless night is not adaptive at all. i.e, becoming lion chow prevents passing on your genes to offspring.

So, sleeping or a dormancy period is adaptive for many species of animals.
It let's them forage and get on with life during times of the day or season (think hibernation) when their physiology has evolved to function well. And keeps them out of harm's way. Canids like dogs and wolves sleep for long periods during the day, since being a scavenger means too much wandering around gets the animal into excessive confrontations that do not necessarily contribute to survival but result in injury, for example.
 
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  • #9
Jellyfish don't have anything recognisable as a brain, not sure if they sleep or not.
 
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@MikeeMiracle
Sleep as you think of it is for higher vertebrates - mammals for example. Jelly fish have a neural net, kind of like a 'protobrain'.

Some jellyfish enter a dormant phase during part of the daily cycle:

Link: "The Jellyfish Cassiopea Exhibits a Sleep-like State"
https://www.sciencedirect.com/science/article/pii/S0960982217310230

Anthropomorphize means attributing human traits to other species. It is a great way to get completely confused on this subject.
 
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  • #11
The koala bear, I believe, sleeps for about 20 hours a day. I suppose you could ask why does it bother to wake up at all?
 
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@PeroK I think they have to eat. Which is hard to do while asleep. Again this is likely an adaptive response. They do change trees and feed mostly at night. Apparently they some trees are favored for spending daylight asleep, and other tree leaves are dinner. Like sloths, their calorie intake from Eucalyptus leaves is relatively low, so not moving much for 20+ hours is adaptive. They do not waste energy moving around a lot - again like sloths which are leaf eaters, too.
 
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  • #13
phinds said:
The heart is not a "creature", it is an organ in a living creature.

Bacteria are "creatures", and brainless, and don't sleep.

That depends what you mean by "sleep". Bacteria can have a 24 hour circadian rhythm, and can enter a dormant state. I think most people would equate sleep to something to do with brains, but the ops question specifically precludes that, which makes it difficult to answer.
 
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.. sounded like the title of a political thread ..! ;)
 
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cmb said:
.. sounded like the title of a political thread ..! ;)
(Sigh.) And here I was,... trying to resist the temptation to point out that (certain subspecies of) internet trolls are an obvious example...
 
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Cobul said:
The cells in the heart keep beating throughout your life. It doesn't sleep. So why is it not similar in the brain?

Are there any brainless creatures like the heart that don't sleep?
I think this question sounds interesting.👍
 

Related to Are there brainless creatures that don't sleep?

1. Are there any creatures that do not have a brain?

Yes, there are several creatures that do not have a brain, such as jellyfish, sea stars, and certain types of worms. These creatures rely on a decentralized nervous system to control their bodily functions.

2. Do brainless creatures have the ability to sleep?

No, brainless creatures do not have the ability to sleep. Sleep is a complex neurological process that requires a brain to regulate and control.

3. Can brainless creatures still exhibit behaviors and movements?

Yes, brainless creatures can still exhibit behaviors and movements. While they may not have a centralized brain, they have other sensory organs and nerve cells that allow them to respond to their environment.

4. How do brainless creatures survive without a brain?

Brainless creatures have evolved to survive without a brain by relying on other mechanisms such as reflexes and instinctual behaviors. They also have decentralized nervous systems that allow them to respond to stimuli.

5. Are there any advantages to not having a brain?

There are some advantages to not having a brain, such as being able to survive in extreme environments and having a simpler, more energy-efficient body. However, having a brain also allows for more complex behaviors and problem-solving abilities.

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