It has been suggested that an all out nuclear war would so enshroud Earth with clouds of dust and smoke that the entire surface of the earth would be quite dark and therefore intensely cold (well bellow 0 deg C) for several years. In that case, it is thought, eukaryotic life would die out and bacteria would inherit the earth. Why??



Because Eukaryotic cells requires a normal temperature (body temperature) in order to live. Extreme temperatures (Below O or above 40 degree Celsius) causes the eukaryotic cells to die, causing its DNA to denatured, resulting in the malfunctioning of the DNA.