Trees have complex interactions with other species, some of which are necessary for their healthy growth.

ECONOMIST: GM trees are on their way

Fuxianhuia protensa, the species of the critter, now suggests that the earliest insects may have evolved from species' that already had a complex brain.

ENGADGET: Alt-week 10.13.12: is the Universe a simulation, cloning dinosaurs and singing mice

The ocean is a complex web of marine life, with many species being driven to extinction year after year.

CNN: Even after attacks on humans, sharks should be protected

Our brains are much better at processing the simple risks we've had to deal with throughout most of our species' existence, and much poorer at evaluating the complex risks modern society forces us to face.

CNN: Stop the panic on air security

From vulcanism to the extinction of species to global climate change and on to creation itself, she tackles complex topics with dexterity.

ECONOMIST: Island life

Most important of all, in offices, on construction sites, on football pitches around the world, the great, complex, social, co-operative endeavours which typify our species and make us human, in all of these you find middle-aged people telling supposedly sharper and stronger young adults what to do.

BBC: Viewpoint: Just what is middle age?

Whales and dolphins have complex cultures, too, which vary from group to group within a species.

ECONOMIST: A declaration of the rights of cetaceans