Human

"There is one facial expression which, more than any other has dramatic signal value— the full closed grin. When this expression suddenly appears, it is as though the whole face has been split by a gash of white teeth set in bright pink gums. It is often given silently, in response to an unexpected and frightening stimulus. When an individual turns to his companions with his face transfigured by this horrifying grin, it usually evokes an instant fear response in the beholders."

- Jane Goodall

Insight: Monkeys, apes, and humans use orofacial gestures as their main natural way to communicate.

Insight: Lip and tongue sounds of monkeys persist in humans - they form syllables in speech.

Insight: On 7 January 1974, Jane Goodall discovered violence among chimp groups in Gombe National Park, Tanzania - something previously believed to be uniquely human.

Insight: Jane Goodall describes chimps doing a wild dance near a waterfall.

• Insight: The growth of our brains in certain areas during our lifetime does not appear to be due to adding new neurons, but the growth of myelin sheaths around specific neurons where continuous use triggers this process.

• Reference: Garrett Hardin, biologist - the Tragedy of the Commons does not distinguish between "open-access free-for-alls" and "communally owned property". Free-for-alls are subject to cheaters, whereas communally owned properties can be carefully regulated.
• Insight: Large, "nationalised" or government managed properties face the problem of too few resources to manage the property, people having incentives to cheat, and it becoming a free-for-all on a large scale.