The cell actually divides in Cytokinesis.
The algae increase the autotrophy by offering photosynthesis to the fungi in the lichen organism.
A lichen is an organism consisting of a symbiotic association between a fungus (the mycobiont) and algae. The mushroom brings water and mineral salts. The alga produces, by photosynthesis, various organic compounds of which it gives a part to the mushroom.
A general ballpark how one can predict the way how evolution will work in the future would be by thinking about the requirement of a certain area or environment and which changes would be necessary and relevant for any organism to thrive with its new changes.
This could help people speeden up this process by enabling organisms to develop such traits faster, as well as ourselves.