Plants in the dark!?

Our initial theory: Plants can only photosynthesis in the presence of sunlight.

A better theory: Some plants can also photosynthesis without the presence of sunlight. In 2005, a team of scientists discovered the first organism that relies on photosynthesis yet lives in a part of the ocean that never gets sunlight.
For exmaple , a green sea slug living in the salt marshes of New England and Canada apparently have stolen the genes of algae they have eaten. They are the only know multicellular animal capable of producing chlorophyll. Consequently, they are able to survive months with just sunlight alone. They can even pass on this gene to their offspring, although the kids have to algae to get enough chloroplasts to start photosynthesis on their own

Animals derive energy through carbohydrates and other chemicals produced by plants through classic photosynthesis. As you exclude Algea and Fungi, I'm assuming that also means you leave out Corals, Mollusks (like Clams) etc. which harbor Algae in their tissue, allowing them to share nutrients directly with their host. That's called symbiotic photosynthesis and it's a 'cheat.'


We'll keep this clean.
In biology, we usually restrict Photosynthesis to the famous equation seen on blackboards across the world: 6H2O + 6CO2 ----------> C6H12O6+ 6O2 "Six water units plus six carbon dioxide units= One unit of sugar and some air" All thanks to that miracle pigment chlorophyll which converts light into energy.



Now, we know that only plants (and probably aliens if you believe bad sci-fis) contain chlorophyll. But what is Photosynthesis? Literally, the term means Photo=Light and Synthesis=Bringing together.



So, If you expand your understanding of photosynthesis and view it more generally as anything that uses light + substance to create a new substance, then things look different:

That's right, those fried eggs that gave Uncle Gerry his stroke and pacemaker could have been turned into vitamins if he'd been a surfer. (well, sort of...) Of course, if he was a vampire, it wouldn't have helped one bit.

To recap: Photosynthesis via Chlorophyll only exists in plants. But the photosynthesis of UV-B rays into Vitamin D (using Cholesterol) is a valid example of animal photosynthesis.