An interesting organism to look into: Elysia chlorotica. This sea slug has a symbiotic relationship with algae that has resulted in the ability to manufacture chlorophyll, the chemical required for photosynthesis. By ingesting photosynthetic algae over many generations, it is proposed that some of the algae's genes, most importantly the ones responsible for chlorophyll production, have become incorporated into the genome of Elysia chlorotica.
Read the article bellow for more information:
Green Sea Slug
