[yason]

What if the question was phrased as what is the real reason we wake up and dedicate some conscious time for our mind? Surely, because in the physical world we live we need to arrange for some time to deal with the unavoidable practical things such as finding food and shelter. Then, after a long enough period of this activity focused on these very tangible, physical and physiological constraints we can finally say we fall to sleep again.

[spyder]

You are saying we wake up just to survive ("finding food and shelter"), but it's right in the article:

“The cost of losing consciousness to survival is astronomical,”

"This means we can confidently reject one of the simplest theories of sleep: that we drift off simply because we have nothing better to do."

[Dylan16807]

Doesn't make sense to me. To take care of those needs, we don't need to be awake nearly as much as we are. On the other hand, staying awake all the time would have moderate efficiency benefits and provide a lot more protection from threats. So we should either be sleeping a lot more or barely at all; the middle ground has no benefit under this model. The model of sleep as recovery works a lot better for the durations we see.

[pluma]

Isn't that basically what the scientist asks in the last paragraph?

> “What about this hypothesis: sleep was the first state of life and it was from sleep that wakefulness emerged,” says Walker. “I think it’s probably a ridiculous hypothesis – but it’s also not entirely unreasonable.”

[personjerry]

Perhaps to that question the answer is: to secure nutrients and safety for our body as we sleep?

[KannO]

We can't all be plants and fungus.

[azeirah]

Plants seem to sleep as well, can't pinpoint the exact source right now, but it was from a documentary. Something among the lines of "the hidden lives of plants"

[samueladam]

http://www.ted.com/talks/stefano_mancuso_the_roots_of_plant_...

[Majestic121]

Why?

I think it is possible for life to evolve on a planet with only plants and fungus.

Plants have been pretty successful down here on Earth, and I think most of them don't need animals for their survival (except flowers?).

[tremon]

I think it is possible for life to evolve on a planet with only plants and fungus.

That's kinda circular, given that plants and fungi are examples of evolved life :)

You are correct that plants don't strictly need help with pollination (they simply release their spores to the wind/current and hope they land on a receptive partner), however the odds of a succesful pollination decrease sharply as the number of competing plants in an area increase.

In my (uneducated) view, in a scenario where all life is stationary (rooted to the ground, hur hur), you are much more likely to find monocultures -- where most plants can interbreed -- or more species using asexual reproduction.

[ComputerGuru]

Flowers don't necessarily need animal life either, though it does help. Wind can pollinate.

[saalweachter]

More importantly, plants evolved in the context of animals; if animals didn't exist, plants wouldn't have evolved seed dispersal or pollination strategies relying on them. They might have even evolved strategies we've never seen, that don't work well when there are animals running around eating everything.

[KannO]

It's too late for that now, for now.