When the first single-celled organisms left behind their loner ways and began existing as blobs of cells, it was a big step for life on this planet. Organisms could now grow orders of magnitude larger than each other. They could organize their cells into different types that performed different functions. Instead of drifting around with the other specks, multicellular organisms could grow, swim, crawl, fly, and evolve into everything else on Earth today.
It's nearly impossible to know how organisms first made the leap into multicellularity. But in an effort to look back in time, researchers in Japan bred collections of yeast cells that competed with each other for food. They found that the innovation of living as a group of cells would have given the first many-celled organisms a clear advantage--and that it may have been spurred by nothing more than sloppy wall building.
Yeast is a single-celled fungus, ...
