SSS 2008-12-01

（单词翻译）

This is Scientific American's 60-Second Science. I'm Cynthia Graber. This will just take a minute.

It may look like just another animal. But one kind of lowly sea slug actually has the solar power abilities of a plant. Bizarre but true, the sea slug carries out photosynthesis¹. This finding was published in the Proceedings² of the National Academy of Sciences.

Usually, plants perform photosynthesis by way of tiny organelles called plastids. Plastids convert sunlight, water and carbon dioxide into usable nutrients³. Then animals eat the plants. But the sea slug goes about it slightly differently.

It has at least one gene⁴ necessary for photosynthesis—so far it’s the only animal known with this ability. But it needs some help, the gene itself isn’t enough. So sea slugs eat algae⁵. They slit⁶ open the organisms and suck out the cytoplasm. The slugs digest most of the algae, but those plastids remain whole and undigested. And then the plastids keep on doing what they do, which is convert sunlight to usable energy. Once the sea slug has eaten enough algae, and gained enough plastids, it can live off just sunlight for up to nine months. When it comes to energy, this slug needs no plug.

Thanks for the minute for Scientific American's 60-Second Science. I'm Cynthia Graber.