Mathematically Optimal Potatoes

Coral isn't a plant.

Corals aren't plants...

D'oh. I was slow.

Not a plant.

Things that look even more like the stuff on pandora are "christmas tree worms", they retract just as quickly and look the same.

I always figured that's where they got the idea? Anyway, what about those little round things in tide pools? I always enjoyed poking them and watching them scrunch up. And those are hardly the only organisms which exhibit such behavior.

I'm pretty sure the idea came from the polychaetes, a class of annelid worms. Yes, they're animals and worms.

As whiterabbit said, I think it's based on "Christmas tree worms" (Spirobranchus giganteus). Here a video: http://www.youtube.com/watch?v=bVJcBRqzr8Y

There are also tube worms that do the same thing in coral reefs. But as almost every one else has said, corals aren't plants.

Cola: tide pools where? There are lots of different critters in different tide pools all over the world.

Pandora envy sweeeps the nation! That is really cool though, makes you think the creators of the film had based the plants on this exact species.
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Um yeah.. it's not a plant, and it's not a coral either!
It's a sea cucumber(an Echinoderm), probably in the order Dendrochirotida.

Here in the Philippines, we have a similar plant. It's called the makahiya. It folds up its leaves when it's touched.

You mean this?

Zava, tide pools in Oregon. I'm pretty sure these critters are common in this climate. I can't seem to find the species, though. It's some kind of anemone. It looks like a little green mouth with fuzzy lips and it scrunches up and closes when you touch it into a little brown lump.

Everything on Pandora was based (in most parts) on stuff you find on Earth. I don't know why people are so surprised to find similar stuff here...

Everything on Pandora was based on a really dumb film.

"Pandora Depression" makes me want to self-hurt.

here in brazil we have a plant that folds its leaves when touched http://www.youtube.com/watch?v=ZP7Y5cv9fP0

In France we have snails...