All further cell divisions from this unicellular stage of the human being occur by simple mitosis.
In the heliocentric perspective, our dear earth is a mere speck in this expanding infinite space where a very tenacious life came into existence in its oceans about two and half billion years ago in a unicellular body - the Amoeba.
However, the evolutionary distance between unicellular organisms and higher plants might be a serious setback when trying to obtain high expression, at the right time and cellular localization, of foreign genes in plants.
Although the evolution of well-mixed, unicellular microorganisms has been studied extensively, the evolution of filamentous microorganisms has not.
An interesting variant of normal photosynthesis is the simultaneous photoevolution of molecular hydrogen and oxygen by certain unicellular algae and in vitro cell-free preparations.
As compared to metazoans, the development of these unicellular organisms is likely less affected by dissociated heterochrony, which is considered a common phenomenon in metazoans.
Second, the existence of unicellular life for one or two billion years without the formation of multicellular life wouldn't be a problem on Mars because it obviously was not a problem on Earth.