We have long since known that plants and algae are capable of using sunlight to synthesize their own energy. They essentially create their own food, and that was, by far, the clear distinction that separated plants and animals. However, nature just blurred that distinction further! Scientists have found that there are some pretty incredible animals that have been doing what we thought was a skill exclusively gifted to plants – photosynthesis.
These unique animals dubbed, ‘photobionts’ are capable of surviving only with light and air. One such animal is the solar powered, sacoglossan mollusc or the sea slug. Now one would imagine that this must be some sort of symbiotic relationship being maintained between a photosynthetic plant and the slug. On the contrary, the sea slug steals the photosynthetic apparatus from the plant/algae it engulfs. It doesn’t just stop at that, it also retains the photosynthetic genes from its meal! And like all animals, the sea slug is not selfish, it also thinks about its future generation. It can actually transfer these “eaten” genes to its off spring, permanently embedding it into its genome.
If an invertebrate practicing photosynthesis has not amused you enough, scientists have recently discovered a vertebrate that is capable of living on sunlight and air. The spotted salamander, often the subject of research (and reptile pet owners fascination), has recently been discovered to have algae in its cells alongside its energy producing machinery (its mitochondria). The salamander’s mitochondrion directly takes advantage of the energy produced by the foreign algal cells. What’s more, it seems that the female can also pass on these cells to its offspring. But the most incredible thing about this association is that while normally an organism would mount a response against a foreign object, in this case the algae seem to have escaped the immune system!
The discovery of such organisms puts forth an inevitable question, if salamanders and slugs can evolve to become photosynthetic, could we do it too? Well now, that, only time can tell!