Are giant jellyfish evolving to take over the seas?

With fish numbers all over the world falling thanks to overfishing and habitat destruction, a surprising predator has sprung up to take their place — the jellyfish. Due to their low energy requirements, the floating blobs of stingers don't need to be quite as active or accurate to spread and fill the ecological niche… » 9/15/11 12:20pm 9/15/11 12:20pm