Whenever we talk about animals and plants, we differentiate them on the basis of two very distinct groups: one converts sunlight into energy and the other has to eat food to produce its energy. However, these separating lines have been wiped out with the discovery of a sea slug that is in fact half animal and half plant. The official name of this sea slug is Elysia chlorotica and the way it has been able to take over the genes of the algae on which it feeds is quite unbelievable.
These slugs are capable of producing chlorophyll, the green pigment in plants that captures energy from sunlight and hold these genes within its body. In order to refer to the practice of using hijacked genes to make nutrients from sunlight, the term kleptoplasty (retention of “stolen plastids”) is being used. Despite the fact that pea aphids and spotted salamanders display some plant-like characteristics, this green sea slug is considered the only known animal that is solar-powered. These sea slugs have been studied by various scientists to ratify their ability to produce energy from sunlight.
As stated by NBC News,
“In fact, the slugs incorporate the genetic material so well; they pass it on to further generations of slugs. The babies of thieving slugs retain the ability to produce their own chlorophyll, though they can’t carry out photosynthesis until they’ve eaten enough algae to steal the necessary chloroplasts, which they can’t yet produce on their own.”
The detailed zoomed pictures of the skin of sea slug have been shown in Karen Pelletreau’s study. The description of Figure A by Karen N. Pelletreau is as follows:
“Fig.A: The digestive system consists of densely packed tubules that branch throughout the animal’s body. Each tubule is made up of a layer of single cells containing animal organelles and numerous algal plastids.”
From the IFL Science website, Sidney Pierce from the University of South Florida said:
“There is no way on earth that genes from an alga should work inside an animal cell. And yet here, they do. They allow the animal to rely on sunshine for its nutrition. So if something happens to their food source, they have a way of not starving to death until they find more algae to eat.”
The sea slugs can survive up to 9 months without eating any food due to such good ability at photosynthesis. They acquire all their nutritional needs by the chloroplasts that they have hijacked from the algae.