Illustration of an imaginary landscape to show evolution and the first appearance of life on earth, due to photosynthesis. Seaweed, due to its ability to photosynthesise, spread rapidly in the ocean and outside it, where its descendents diversified in the form of terrestrial plants. But another form of life appeared, animals, illustrated here by shell ammonites and a mosasaur in the aquatic depths on the left of the illustration.