Earth is full of mesmerizing species and finding new ones is always fascinating and truly a phenomenal experience. But even finding details about the existing species that were once unknown is also quite amazing, because as much as we think we have explored our planet the truth is that we have barely scratched the surface. Therefore, coming across animals that exhibit strange characteristics is something that we should become accustomed to because we don’t know everything, clearly. Just like a sea slug that’s also a plant.
While we are familiar with the land snails and slugs that usually surface after rain, we tend to forget about the slugs that reside in the waters. Nudibranchia is the scientific name given to these organisms and this name is Latin for exposed gills, as it doesn’t have any shell and have feather-like gills. Some unique things about these are the presence of horns, each species of sea slugs also known as gastropod mollusks have some sort of horns, and all of them contain both male and female organs, and during mating both releases eggs. Some of them are also poisonous.
If that was not interesting enough, these animals are cannibals and are often observed eating their own kind. There are over 2,000 species of these gastropods with each one with exuberating and vivid colors or patterns.
The Plant Slug
Now with having over 2,000 species one will expect it to be of different shapes and few dissimilar characteristics, however, one of the types is not like the others. Well, it is not like any other animal on the planet. We have a very distinguished difference between plants and animals, but this slug blurs this line as it is part animal, part plant.
A vibrant green slug that appears like a fresh or sometimes wrinkled leaf is known as Elysia chlorotica. Though there are other animals on the Earth that mimic the appearance of plants to save themselves from predators, Elysia chlorotica takes it on a completely different level as it becomes a plant itself. It is about 5 cm long and one of the most captivating facts about it is that only after eating for 2 weeks it can spend the rest of its life without eating. How do you ask? Photosynthesis, that’s how. According to the researchers, their favorite food is responsible for it, an alga known as Vaucheria littorea. As you might be familiar that chloroplast is responsible for photosynthesis, this confuses researchers even further as this substance only contains about 10% of the proteins required that allow these slugs to sustain life. This led to further research.
The Gene theft
According to scientists, these slugs are able to perform photosynthesis by stealing genes from Vaucheria littorea. They conducted an experiment to see if only the chloroplast was absorbed from the algae that they eat and if this was the case, they’d be utilizing some other means to photosynthesize. After looking into the DNA of the slugs they found that algal genes were, in fact, present in their cells, not only that but their sequence was identical to that of the algae. As these slugs are not born with such genes, one explanation for this is that they stole them from their food, and then it is slowly incorporated in their cells which enables them to do so. Another explanation is that a certain type of virus present within these slugs carries the DNA from the algae to the cells of these animals, but how it is later switched on in the body of sea slugs is still a mystery. One surprising finding is that these genes have been found in the sex cells of these animals, so probably they pass it down to newer generations.
To this day, it is truly a confusing and interesting species, as hundreds of other herbivorous animals consume plants and similar algae as well on the daily basis, however, none of them are able to utilize the Sun’s energy the way these slugs can. If we happen to figure out how exactly they use photosynthesis then is it possible that it can be incorporated into humans? I believe these questions have to wait until we figure out how exactly this plays out.