Eukaryotic photosynthetic organisms (including the fungi).

Plants and animals belong to the large group of eukaryotes. The main difference between the two groups is the additional endosymbiosis of the precursors of plant cells with photosynthetic bacteria in the course of evolution. (These bacteria finally evolved into chloroplasts). Some unicellular algae and a number of multicellular plants lost the ability for photosynthesis during their further evolution. In contrast to the definition given above, these organisms are grouped together with the photosynthetic plants. In addition, the non-photosynthetic fungi are included in the plant group, due to a number of features they are sharing with plants.