Let me share a little theory I have about optimism, and why progress is so easy to underestimate. I’ll explain it in four parts. A crocodile in Costa Rica was found pregnant recently – and she did it all herself, with no help from a male. Her fetus is 99.99% genetically identical to her. It’s the first documented case of a crocodile reproducing asexually. A few other animals – some birds and snakes – can do it as well, but it’s extremely rare. There’s a good reason why. Almost 100 years ago, an evolutionary biologist named Herman Muller came up with a theory that eventually became known as Muller’s Ratchet. It says ... (full story)