IMHO, sleep is an integral part of an animal life cycle. Some animals even hibernate!

Also, the sleep pattern varies from animal to animal probably because each of their life cycles are different. Most animals sleep at night but, of course, not all!

Cats, bats and owls, among others, seem to be awake at night...

But to be awake at night when one cannot see very well, is definitely a unique characteristic, like for example, bats use radar to navigate at night...

You say that "as an individual progresses in meditation and/or prayer he or she needs less and less sleep". Well, since sleep is directly related to time-space synchronization, one that can find alternatives to sleep and still maintain synchronization should, in theory, be able to not need as much sleep. However, synchronization is an issue of control and of being able to maintain proper reference, therefore, it requires a lot of extra energy to do that and this is probably why the body must go to sleep!

You also say that "there appears to be some validity in this claim, especially in regards to those who seem to have more or less conscious control of their brain wave activity". I would also tend to agree with that. But, like I said above control requires a lot of extra energy which is very hard to maintain in a conscious state of mind!

I personally see control as layer 6 which is above awareness (layer 5) which is above consciousness (layer 4). So, in order to achieve higher control, one has to achieve higher and higher awareness which transcends consciousness...

Awareness is also known to some people as the subconscious which is a much bigger domain than the conscious.

-wirelessguru1