A science writer is sure diatoms evolved, even if their origins and intricate designs are major mysteries.

Michael Gross, a science writer at Oxford, wrote a feature story for Current Biology called, “The Mysteries of the Diatoms” (Current Biology, Volume 22, Issue 15, R581-R585, 7 August 2012).   Gross knows that diatoms are extremely successful and diverse, very important for the carbon cycle, and beautiful to look at, but said scientists still know little about them.  One of the chief mysteries is their evolution:

Diatoms — single-celled algae typically enshrined in a cell wall made of intricately laced silica — have fascinated researchers with a whole range of mysteries, from their evolutionary origins through to their morphogenesis and reproduction. They entered the plant kingdom rather late in evolution, and through an unusual entry. Researchers believe they are secondary endosymbionts, meaning that their precursor was a eukaryote that engulfed another eukaryote, resulting in a quadruple membrane around the chloroplasts the diatom gained from this act of piracy.

The evolutionary success story of diatoms only begins some 200 million years ago, but they have spread around the globe and diversified into hundreds of genera and around 100,000 species in this short fraction of the geological timescale. Today, they are present wherever there is liquid water, in the oceans, in freshwater, and even in soil. They have already played a significant role in the global cycles of carbon and nitrogen, and are responsible for large sediments of silica including diatomaceous earth….

 

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