The earth was empty. Nothing grew, swam, crawled in the vast ocean that covered their surface. Its water was hot, germ-free and like the whole planet a very inhospitable place. But not for Luca. It had everything it needed in abundance. That wasn't much: Luca needed water for his metabolism and lived on gases. It didn't need oxygen to breathe; it never existed either in the atmosphere or in the water. It would take four billion years before humans came into being. A long time, and she started with Luca.
Evolution: the beginning of life
Everything that breathes and blooms on earth today descends from a primeval being. It existed four billion years ago and was still less than a single cell. Researchers call it "Luca".