Q. Which type of cell came first in evolution - the eukaryotic cell or the prokaryotic cell?
This is an interesting problem of biological evolution. The majorly accepted hypothesis asserts that the prokaryotic cell, the simpler cell, appeared earlier in evolution than the more complex eukaryotic cell. The endosymbiotic hypothesis, for instance, affirms that aerobic eukaryotic cells appeared from the mutualist ecological interaction between aerobic prokaryotes and primitive anaerobic eukaryotes.