Eu" means "true," and eukaryotes have DNA arranged in chromosomes and encased in a nucleus. Fossil evidence indicates that prokaryotic cells first existed on the earth, prior to the arrival of the eukaryotes.
eukaryotic cells evolved from a symbiotic association of prokaryotes—endosymbiosis—is particularly well supported by studies of mitochondria and chloroplasts, which are thought to have evolved from bacteria living in large cells.
