- Joined
- Nov 20, 2002
- Messages
- 1,073
While watching CORAL SEA DREAMING, one of my fav DVDs, I noticed some sort of pretty reef fish described by the caption as "sleeping in a mucus bubble". Which I assume answers the question of whether fish sleep.
But then I got to thinking about this whole mechanism of sleep and dreams. We all know that mammals, birds, reptiles, amphibians, and even fish sleep. But when we get to the invertebrate level, is sleep still part of the picture?
I somehow doubt this would apply to, say, bivalves, jellyfish, corals, sponges, earthworms, protozoa, and bacteria.... but what about "higher" inverts such as insects, arachnids, crustaceans, and (you knew this was coming ) cephs? Do they sleep, or have a biological process similar to sleep?
And if any of the above inverts do sleep.... do they dream? For that matter, do birds, reptiles, amphibians, and fish dream? Everyone here has seen a dog or cat wildly chasing imaginary prey in dreamland, but I don't know how one would measure REM sleep in non-mammalian species.
Maybe this could best be summarized by two basic questions:
1. At what point on the evolutionary ladder does the ability/necessity to sleep begin?
And, having determined that....
2. Among those species which do sleep, at what point on the evolutionary ladder does the ability/necessity of dreaming (as indicated by REM sleep, for want of a better criterion) begin?
This may sound silly, but I am genuinely curious about the whole thing..... which keeps me awake at night. Literally. Steve-O'? Kat? Monty? Nancy? Anybody?
Tani
But then I got to thinking about this whole mechanism of sleep and dreams. We all know that mammals, birds, reptiles, amphibians, and even fish sleep. But when we get to the invertebrate level, is sleep still part of the picture?
I somehow doubt this would apply to, say, bivalves, jellyfish, corals, sponges, earthworms, protozoa, and bacteria.... but what about "higher" inverts such as insects, arachnids, crustaceans, and (you knew this was coming ) cephs? Do they sleep, or have a biological process similar to sleep?
And if any of the above inverts do sleep.... do they dream? For that matter, do birds, reptiles, amphibians, and fish dream? Everyone here has seen a dog or cat wildly chasing imaginary prey in dreamland, but I don't know how one would measure REM sleep in non-mammalian species.
Maybe this could best be summarized by two basic questions:
1. At what point on the evolutionary ladder does the ability/necessity to sleep begin?
And, having determined that....
2. Among those species which do sleep, at what point on the evolutionary ladder does the ability/necessity of dreaming (as indicated by REM sleep, for want of a better criterion) begin?
This may sound silly, but I am genuinely curious about the whole thing..... which keeps me awake at night. Literally. Steve-O'? Kat? Monty? Nancy? Anybody?
Tani