Plants are autotrophes, they can harnass the raw untamed power of the sun and use it to make food for themselves, pretty impressive, so why can’t animals do it? Well, oddly enough some of them do. In just the past few years researchers have been discovering animals that seem to be able to harvest sunlight for energy. Take for instance the Eastern Emerald Elysia, a sea slug that looks like a big fl;oating leaf, it just hangs out eating a specific kind of yellow green algae. Its been known for a long time that this slug had a special relationship with the algae, but until recently nobody knew that the slug was actually using the algae’s genes for photosynthesis. The slug eats the algae to absorb it’s choloroplasts, the organelles in the cells that actually do the photosynthesizing. But in order to turn the sunlight into chemical energy, the choloroplasts need a whole set of specialized proteins to help, so the slug has lifted genes from the algae that allow it to make these proteins itself. Nobody’s sure exactly how this happened. But we do know that these slugs pass those algal genes onto their little baby slugs, which only need to eat about 2 weeks of the year, the rest of the year they’re just soaking in the rays. aAnother photosynthesizing animal is the pea aphid, which dependending on environmental conditions at birth can either be white orange or green. Aphids are notoriously weird, some of them can be born pregant, some males are born with no mouths and die of starvation right after mating. So it’s no suprise pea aphids have been found to manufacture their own Carotenoids. Colorful compounds that plants, fungi, and some algae use to help with photosynthesis. Carotenoids help plants absorb more light and protect their cholorphyll molecules which make photosynthesis possible. Animals need carotenoids too, Beta-Carotene, a precursor of Vitamin A is one you prbably heard of, but we can only obtain them by eating plants that make them, but since pea aphids have somehow acquired the genes to make their own carotenoids, scientists have found that some aphids depending on their color, can use sunlight to make adenosune triphosphate or ATP, the same energy storing molecule that plants make through photosynthesis and that we make by metabolizing food. Researchers found that aphids with green carotenoids make a whole lot more ATP than White Aphids do, while orange Aphids make more ATP when exposed to sunlight than wehn kept in the dark. The spotted Salamander common to the eastern united states and canada is the first and so far only known photosynthetic vertebrate.In 2010 scientists discovered that these salamanders have chlorophyll-contianing algae in their cells all over their bodies and the cells with algae in them actually seem to help power other nearby cells. No one’s sure how this relationship came about, but the algae has been found to first appear in the salamander’s fertilized eggs. Possibly when the embryos are just big enough to feed the algae with their waist, creating a kind of algal bloom inside the eggs. The algae then entwered the embryo’s body, probably when the nervous system first forms and they spend the rest of their lvies together. All of this is suprising because vertegbrate’s immune systems generally destroy foreign stuff that tries to live inside their cells. But this salamaner and the algae seem to be a match made in heaven. Now that we understnad them, who knows, maybe humans could be next.

Green sea slugs are green because of algae, they get a nice camoflauge from the algae but they get an even crazier benefit from it, some sea slugs are able to live for many months at a time without eating because they feed on sunlight like a plant, because of a symbiotic relationship with algae. Early in 2015 a study published in the biological bullitin explained that they found evidence of some of the emerald green slug’s chromosomes, which mcame from genes of the algae that it ate. The genes made it so the sea slug could have the photosynthetic processes happening within its body so it didn’t need any food. Basically, it ate it and took its power, that’s so cool. Humans could use this one day, but what else can algae implants do? Algae could also help human breath underwater. According to a study published in early 2011 in the precedings of the natural academy of sciences, future humans might eventually be algae implants and also like the green sea slug, use algae symbiotically. Mitochondria have already done it to us. Works the same way as a virus. Viruses invade an organism, integrate its dna into the dna of the host, but scientists were curious if microbes could do that too so the biologists decided to study the relationship between algae and salamanders. Algae has been known to enter the developing salamander egg and become a part of the salamander fetus, it does this before the egg has any kind of immune system to kick it out. Then the algae DNA shows up in adult salamanders, which then they pass on to their young. The algae is mutating the salamnder. The reason that this happens is because of a symbiotic relationship between the salamander and the algae. The algae ate the nitrogen in the Embryo’s waste, the slamander embryo. The embryo then would feed on the oxygen from the algae’s waste, basically they were eating each other’s poop. This means that algae could be sort of an internal source of oxygen. It became a symbiotic relationship and we might be able to do that too. Te’re gonna try to have it live withinvertabrate human tissues as well. Wouldn’t it be cool if you could jump in a lake and you’re little algae started giving you oxygen, then you’d dry up on the beach and feed off the sun for lunch. Of course, we don’t yet know if it would turn our skin green and whether we would actually be able to live with that. In the animay series Sidonia No Kishi, or Knights of Sidonia, the human race lives in a colony ship and are geneticlaly engineered to feed on the sun in order to conserve their food supply.