Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.

Archive for June, 2010

1 Jun

Deconstructing Vitamin D

sunBefore phototropic plants began bending toward sunlight, before jellyfish developed ocelli, the light-sensing organs that allow them to distinguish between up (sunlight) and down, before the bikini-clad beach denizens began tanning en masse, and before the first house cat followed the sliver of sunlight around the room all afternoon, our primitive, microscopic marine forebears were flourishing by converting the sun’s energy into chemical energy usable by biological life. You’re probably aware of photosynthesis, the process by which plants, algae, and other organisms do it and produce byproducts like oxygen, but even the unicellular archaea that do not produce oxygen utilize sunlight for energy. And if you aren’t obtaining energy directly from the sun, you’re probably eating the organisms that do. Either way, sunlight directly or indirectly supports all life (well, except for the chemoautotrophs living in deep sea hydrothermal vents feeding off of inorganic energy sources like iron, ammonia, or sulfur).

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