What is the scenario for the endosymbiotic theory?
The endosymbiotic theory seems easy to understand, a bacterium engulfed by another cell. Apart from the problems in identifying the host, there is ambiguity whether the invader was single- or double-membraned but they distinguish between two different scenarios. The first is a eukaryotic cell that engulfed a bacterium by invagination of the membrane (here), thereby providing the newly derived endosymbiont with the extra membrane. I cannot take this scenario seriously, although it appears in most major textbooks. In genetic evolution, it is essential that new functions are reflected by genomic changes. In this case, the encapsulation should also persist after numerous cell divisions, and the eukaryotic cell should thus be able to put an extra membrane around dividing bacteria. This supposed event is clearly Lamarckian since the developmentally acquired outer membrane would have to been passed to the germline, clearly in contrast with genetic determinism. Moreover, it assumes evolutionar
