Osmotroph

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An organism that eats by osmosis, relying on nutrients diffusing into its body from a higher concentration in its environment.

About 550 million years ago, ambitious aquatic fronds began growing taller and tapped into more nutrient-rich water than found at the seafloor surface. Researchers simulated fluid flow over early multicellular osmo-trophs, which may be early precursors to animals, and found that taller fronds absorbed more nutrients.

The fronds grew up to 2 meters tall at a time when oxygen levels were just beginning to rise on Earth, setting the stage for more complex life to follow, the researchers report February 3 in Current Biology. 

David Gold of UCLA discusses what scientists are learning about the evolution of the earliest multicellular life on Earth.
Credit: M. Ghisalberti et al/Current Biology 2014