Cell differentiation controls iron assimilation in a choanoflagellate.

Summary: Imagine a tiny creature in the ocean, a "choanoflagellate," which is actually one of the closest living relatives to animals. Scientists have discovered that these microscopic beings have a special trick: they can change their physical form—a process called cell differentiation. This isn't just for looks; this shape-shifting ability acts like a switch that controls how well they absorb iron from the water. Because these creatures are so abundant, their ability to "eat" iron essentially helps control the chemistry of the entire ocean. It turns out that the life history of a single cell plays a massive role in the planet's ecological health.