On the nature of the earliest known life forms

Abstract

Archaean Eon microfossils were known to have the most complex of prokaryotic morphologies. Given the morphology of an organism is governed by information encoded in its genome, it was proposed that these primitive organisms most likely possessed molecular biological processes. Here we worked with bacterial protoplasts, incapable of regulating either their morphology or reproductive processes. We then exposed these cells to environmental conditions of Archaean Earth to understand if cytological complexity of microfossils is a result of biological or ecological factors. As we reproduced the morphologies of all known Archean microfossils, we propose that complex morphologies of these microfossils could be explained not by presence but by complete absence of molecular biological mechanisms. Environmental conditions and architecture of the cell membrane are the only factors that determined the morphology of these organisms. Based on our observations we argue against the use of morphology in systemic paleontology and present a case for reinterpretation of Archaean microfossils as liposome like protocells.