Ernst Haeckel proposed the
Ernst Haeckel proposed the three kingdom system of classification in 1866. The three kingdoms include:
• Kingdom Protista: It includes unicellular and colonial prokaryotes and eukaryotes such as bacteria, algae, fungi and protozoans.
• Kingdom Plantae: It includes multicellular eukaryotic photosynthetic plants.
• Kingdom Animalia: It includes multicellular eukaryotic heterotrophic organisms.