The talk: a brief explainer of sexual dimorphism

"Everything in the world is about sex, except sex. Sex is about clonal interference." – Oscar Wilde (kind of) As we all know, sexual reproduction is not about reproduction. Reproduction is easy. If your goal is to fill the world with copies of your genes, all you need is a good DNA-polymerase to duplicate your genome, and then to divide into two copies of yourself. Asexual reproduction is just better in every way: It's pretty clear that, on a direct one-v-one cage match, an asexual organism would have much better fitness than a similarly-shaped sexual organism. And yet, all the macroscopic species, including ourselves, do it. What gives? Here is the secret: yes, sex is indeed bad for reproduction. It does not improve an individual's reproductive fitness. The reason it still took over the macroscopic world is that evolution does not simply select for reproductive fitness.1 Instead, the evolution of sexual dimorphism is a long sequence of strange traps, ratchets and outer-world eldritch

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• Grace Zhang