All plants, animals, algae, fungi and protists share a common ancestor – the eukaryotes are monophyletic. This means that plants did not evolve from one type of bacteria, and animals or fungi from other types. On the contrary, a population of morphologically complex eukaryotic cells arose on a single occasion – and all plants, animals, algae and fungi evolved from this founder population. Any common ancestor is by definition a singular entity – not a single cell, but a single population of essentially identical cells. That does not in itself mean that the origin of complex cells was a rare
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