The Doctor: 'Homo sapiens. What an inventive, invincible species. It's only been a few million years since they crawled up out of the mud and learned to walk. Puny, defenceless bipeds. They've survived flood, famine and plague. They've survived cosmic wars and holocausts. And now, here they are, out among the stars, waiting to being a new life. Ready to outsit eternity. They're indomitable... indomitable.'
The Ark In Space