kongx8 t1_irevs0g wrote

It is thought that euglena split off from the plant/green algae line before the development chloroplasts from captured Cyanobacteria. It likely that Euglena’s ancestors received their chloroplasts from engulfing an eukaryotic green algae. Over time, the engulfed algae was reduced to a chloroplast and a nucleus, thus serving a similar function to the original chloroplasts.