If the population of humans on Earth dwindled to just one man and one woman, I’m willing to wager that Homo sapiens would soon be extinct. That’s because whatever catastrophic event(s) led to the extreme thinning of the ranks would soon claim the last of us. 

Ignoring that likely outcome, Zoria Gorvett at BBC Future presents a thought experiment: If you place a post-apocalyptic Adam and Eve on Earth with just one another, would they be able to repopulate the planet? Well, they’d have to fuck like bunnies, and think of the incest! It’s actually best not to think about it. Hundreds of years of inbreeding would not be pretty, in any sense. Even if people somehow survived, the lack of diversity would probably cause us to transition into a different species. The most positive way to look at it? Anything’s possible.

The opening:

The alien predators arrived by boat. Within two years, everyone was dead. Almost.

The tiny islet of Ball’s Pyramid lies 600km east of Australia in the South Pacific, rising out of the sea like a shard of glass. And there they were – halfway up its sheer cliff edge, sheltering under a spindly bush – the last of the species. Two escaped and just nine years later there were 9,000, the children and grandchildren and great-grandchildren of Adam and Eve.

No, this isn’t a bizarre take on the story of creation. The lucky couple were tree lobsters Dryococelus australis, stick insects the size of a human hand. They were thought to be extinct soon after black rats invaded their native Lord Howe Island in 1918, but were found clinging on in Ball’s Pyramid 83 years later. The species owes its miraculous recovery to a team of scientists who scaled 500ft of vertical rock to reach their hiding place in 2003. The lobsters were named “Adam” and “Eve” and sent to start a breeding programme at Melbourne Zoo.

Bouncing back after insect Armageddon is one thing. Female tree lobsters lay 10 eggs every 10 days and are capable of parthenogenesis; they don’t need a man to reproduce. Repopulating the earth with humans is quite another matter. Could we do it? And how long would it take?•