This post is an unexpected sequel to a post I published last month about how single-celled microbes can evolve into multicellular bodies.

Here’s a quick recap of that story. Life became multicellular at least a couple dozen times over the past few billion years. To explore the factors that drove life through these transitions, scientists at the University of Minnesota ran experiments with single-celled yeast. They gave the yeast time to settle in a flask and then drew out some fluid from the bottom. Repeating this many times created conditions in which the yeast quickly evolved  into snowflake-like clumps. Bigger clumps fell faster, providing a reproductive advantage over single-celled yeast, which drifted slowly to the bottom of the flask.

This week a