Complex Extremophiles

[Dartz]

Sorry if these posts are too frequent, but I'm trying to be as scientifically accurate as possible in my writing. Google helps some, but I can't seem to find some of what I need. My strong suit is Astronomy, and some Physics, but I haven't studied much on Biology to do much.

The basic question is: Can Extremophiles, particularly temperature-based, form complex organisms? Is there anything that would prevent them from doing so?

[vh]

extremophiles are pretty much all simple and single celled because it's easier to adapt. there are some complex ones though, i think: http://en.wikipedia.org/wiki/Giant_tube_worm

[Bla]

Pompeii worms'/Alvinella pompejana have parts of their bodies which are persistently 353K, and only single-celled bacteria are known to survive in higher temperatures. They can become 10 cm long.

http://news.nationalgeographic.com/news/2004/12/1208_041208_pompeii_worms.html

[smjjames]

Well, is the planet that you are using, a hot planet or something? Because honestly, extremophiles are extreme for Terran life, so, who knows what would evolve on a world that is significantly hotter than ours (but is still able to support complex life).