The Mystery of Sleep
One common alternative conception is that animals gain energy from sleeping at night. This is in fact false. Animals obtain energy from consuming other matter and [producers]] from the sun or chemical reactions. Sleep is a phenomenon of it's own.
Common Alternative perceptions about sleep:
Sleep is a time for the body and specially the brain to turn off and rest. A good nights sleep is the solution to being sleepy during the day.
Functions of sleep:
Sleep is essential for [living]]. Sleep deprivation in humans can lead to paranoia, hallucinations and ultimately death. Even though scientists know the effects of lacking sleep they are still investigating its actual function in the body.
Sleep allows for the restoration and recovery of our biological systems: When you are awake your body is consuming energy and breaking down but while sleeping your brain can bring out the tool belt and fix the leaky faucets. While sleeping your motor functions decrease and you have a lower metabolic rate greatly and your brain has an opportunity to repair. Protein-synthesis decreases during sleep so it is a sort of fasting. Although there is not much evidence that more repair happens during sleep than during a restful awake period.
Sleep allows for energy to be conserved:
Imagine how much energy you would have to consume to stay awake all the time! During sleep our metabolic rate is lower. Species with longer sleep hours have higher core body temperature and metabolic rates needing more energy to operate. During sleep there is les thermoregulation so the body can conserve energy. NREM and REM sleep only occurs in endothermic animals. Exothermic animals can sometimes go weeks without eating (Think snakes!). Also, when you are sick our body emits molecules that are powerful sleep inducers. We go to sleep and then have more energy and resources to fight infection.
Sleep allows us to consolidate our memories:
Sleep gives our brain a chance to sort out what we learned, file away the good stuff and trash the rest. In a study of songbirds, while young song birds are learning songs and practicing their tones the same part of their brain is lit up when the scientists played a recording of their own song to them while they were sleeping. So in theory the song birds are dreaming of singing! Studies also show that getting a full night's sleep helps humans improve in their ability to perform spatial tasks.
Sleep protects animals from predators:
If we are asleep in bed or in our den hungry owls will not eat us!
Sleep helps our brain develop:
When we are younger we have longer periods of deep REM sleep.
Discharge of emotions:
During the REM sleep it is thought that we can discharge emotions from the day before. Muscular paralysis occurs during REM sleep so we can’t act out what we are dreaming. Thank goodness! Also the part of our brain that controls emotions, decision-making and social interactions mellows out during sleep.
All of these hypotheses have flaws. Primarily because wakeful resting hold similar properties to sleep in al these ways!
More information on sleep and teaching it to your students:
National Institutes of Health, BSCS (Biological Sciences Curriculum Study) http://science.education.nih.gov/supplements/nih3/sleep/guide/info-sleep.htm