The life cycle of a snowflake yeast. The snowflake forms evolved from single-celled yeast cells by selecting for larger clusters. Over time, they maintain these large cluster forms and do not revert to single cells—i.e., they have been evolutionarily selected for multicellularity. New cells are added to the growing branches, increasing the size of the cluster. Initially, the snowflakes were split by the physical strain of their size, like a branch of a tree that has grown too long to remain attached. Over generations, though, specialized cells have now evolved that commit deliberate,
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