sleep 100%

Explain the adaptive-inactivity theory of sleep.

Lack of inactivity that results from sleep may have helped animals to survive according to evolutionary perspectives. As a result, they weren't as exposed to danger, which increased their chances of surviving. The adaptive-inactivity theory of sleep posits that sleep is a product of continuous evolution. The theory states that humans need to sleep now because it was advantageous for them to have slept in the distant past. Humans slept at night because they were safer asleep in one spot during the night than if they had been hunting for food in the day, especially since their eyesight at night was so poor.

Describe each of the five unique stages of the sleep cycle.

The sleep cycle has five stages: stages 1-4 and the REM (rapid eye motion) sleep stage. Stages 1-4 are also known as NREM or non-REM sleep. During stage 1 sleep, the brain is dominated by theta waves. The sleeper is in a very light sleep with closed eyes, but the sleep is very light and it is easy to be woken up. Indeed, sometimes a person wakes up with a start in a phenomenon called a hypnic jerk. During stage 2 sleep, the sleeper's muscles begin to slowly contract and relax as the sleeper twitches. The body begins to slow: heart rate, breathing pattern, and body temperature all fall during this stage. The brain continues to be dominated by theta waves, but it will begin to contain deeper delta waves. Stages 3 and 4 sleep are very similar. Usually, scientists differentiate the two categories by stating that during stage 3, less than 50 percent of brain waves are delta waves, and during stage 4, more than 50 percent of brain waves are delta. Some scientists are even beginning to classify these groups together into one stage 3 category dominated by delta waves. It is during these stages of sleep that the sleeper is most deeply asleep and is receiving the most intense physical and psychological recovery. The last stage of sleep is known as REM sleep, so named because of the rapid eye movements that accompany its occurrence. During this stage of sleep, the sleeper's brainwave pattern begins to show much more activity. In fact, the brain waves of this stage closely resemble the alpha or beta wave pattern of an awakened person. It is during this stage that a person will experience dreams.

An extended state of considerably slowed down body functions is known as __________. A. hibernation B. insomnia C. stupor D. torpor

a

During which stage of sleep does body temperature begin to fall? A. stage 2 sleep B. stage 3 sleep C. stage 4 sleep D. REM sleep

a

Sleep could be best described as a __________. A. car with the engine started, but parked and idling B. truck driving on the freeway in the right lane C. train with cargo being loaded at the start of a trip D. bicycle riding uphill in the wind

a

Which of the following most accurately describes the brain during sleep? A. The brain goes dormant and does not emit brain waves. B. The brain remains active and emits brain waves. C. The brain goes dormant and emits brain waves. D. The brain remains active and does not emit brain waves.

b

According to the energy conservation theory of sleep, sleep is an adaptive behavior because sleep __________. A. generates new energy for daily activities B. can regenerate and heal injuries quickly C. allows organisms to consume fewer resources D. allows organisms to escape from danger

c

Sleep stages are defined in terms of the __________. A. amount of time spent sleeping B. length of restful sleep experienced C. occurrence of brainwave patterns D. number of dreams experienced

c

Which of the following brain waves is associated with a deep sleep? theta waves alpha waves delta waves beta waves

delta waves

As the sleep cycles continue, the proportion of REM sleep in each cycle decreases. t/f?

false

Most land mammals have the ability to rest one hemisphere of their brains at a time. t/f?

false

Sleep is a form of consciousness. t/f?

true

Sleep is an universal biological need. t/f?

true

Some psychologists suggest that sleep has evolved in order to allow humans to dream. t/f?

true

The average adult needs about seven to eight hours of sleep per 24-hour day. t/f?

true

The brain remains active during sleep. t/f?

true

The reasons for sleep are poorly understood. t/f?

true

Unilateral sleep refers to the ability to sleep with only one side of the brain. t/f?

true

How many times does REM sleep generally occur during the average sleep? 1-2 times 3-4 times 5-7 times 9-11 times

5-7 times

Compare the sleep cycle of a dolphin to that of a human being.

A dolphin's sleep cycle is very different from that of a human being. A dolphin's unique biological situation (conscious breather, aquatic animal) makes it so that sleep, which rests the entire brain and is occasioned by the loss of conscious behavior, would be fatal. Instead, dolphins sleep with only one half of their brain at a time, and they regularly come to the surface for breath during one of their sleep cycles.