For the John Templeton Foundation, I wrote about how molecular studies challenge and illuminate the historical pathways of evolution.
Stephen J. Gould famously suggested that if you could somehow “rewind the tape of life” and let the evolutionary process play out again, the results would likely be completely different. It’s a fascinating thought experiment that gets at the tension between contingency — evolution’s dependence on random mutations — and determinism — the idea that the constraints under which natural selection operates would steer evolution in similar patterns no matter how many times you rewound the tape.
When Betül Kaçar, an experimental biologist and paleogeneticist at the University of Arizona, first heard about Gould’s thought experiment, she was intrigued. She realized that Gould’s idea didn’t have to remain a thought experiment — it was something that could be studied at a small scale in a modern lab. Over the past several years, Kaçar has done just that.