23.1: Eukaryotic Origins Last updated Mar 6, 2021 Save as PDF 23: Protists 23.1A: Early Eukaryotes Page ID13576 BoundlessBoundless ( \newcommand{\kernel}{\mathrm{null}\,}\) Topic hierarchy23.1A: Early EukaryotesProtists are eukaryotes that first appeared approximately 2 billion years ago with the rise of atmospheric oxygen levels.23.1B: Characteristics of Eukaryotic DNA23.1C: Endosymbiosis and the Evolution of Eukaryotes23.1D: The Evolution of Mitochondria23.1E: The Evolution of Plastids