Predation (the eating of one living organism by another for nutrition) predates the rise of commonly recognized carnivores by hundreds of millions (perhaps billions) of years. It began with single-celled organisms that phagocytozed and digested other cells, and later evolved into multicellular organisms with specialized cells that were dedicated to breaking down other organisms. Incomplete digestion of the prey organisms, some of which survived inside the predators in a form of endosymbiosis, might have led to symbiogenesis that gave rise to eukaryotes and eukaryotic autotrophs such as green and red algae.
predation (the eating of one living organism by another for nutrition) predates the rise of commonly recognized carnivores by hundreds of millions (perhaps billions) of years it began with single-celled organisms that phagocytozed and digested other cells and later evolved into multicellular organisms with specialized cells that were dedicated to breaking down other organisms incomplete digestion of the prey organisms some of which survived inside the predators in a form of endosymbiosis might have led to symbiogenesis that gave rise to eukaryotes and eukaryotic autotrophs such as green and red algae