Cavedge Solar Cell
The cavedge solar cell replaced its ancestor the solar flash cells. This has occurred due to the fact that mutated cells near the cave edge reduced their constant flashing and have started to use it like their early ancestors did only to scare off filter feeders. Due to this the population deeper inside the cave died out and the solar cells only covered the cave edges and areas where outside light could enter. Still when flashing using bioluminescence in order to scare away enemies nearby caveedge solar cells can use this light for energy but this is a minor secondary source now.
Their energy storing organelle around their nucleus has further evolved and has now changed to become more labyrinth in order to have more surface area. It now works by kipping electrons on one side of the inner membrane and using reduction materials to harness that energy. This way it can store the energy for very long periods of time. As the winters in the poles can be very long and cell lives are very short one can easily see that generation that grow in the winter only live on the very edge of the cave while generation that grow in the summer are more abundant and grow a little deeper.