Kingdoms call the second in order hierarchical step in classification of living organisms. In total biologists allocate eight kingdoms: Animals, Mushrooms, Plants, Bacteria, Viruses, Arkhei, Protista and Hromista. Scientists cannot precisely tell what kingdom the most ancient, Arkhei and Bacteria fight for this rank.
Kingdoms of living organisms unite in four nadtsarstvo: Archean, viruses, bacteria and aukariota. The last are characterized by existence of a kernel, they include animals, mushrooms, plants, protests, hromist. They cannot be considered as the most ancient as the kernel is later evolutionary acquisition. Only nuclear-free organisms can be the first living beings on Earth: it were either Arkhei, or the Bacterium. Viruses developed much later, presumably, about 300 million years ago.
Kingdom Archean
The Archean is the simplest unicells which do not have a kernel and membrane organellas. Earlier these beings were considered as bacteria and entered the kingdom of Bacteria (called also Drobyanki or Monera). Their official name was archaebacterias, but today scientists consider it outdated and call these organisms only of an arkheyama. It was found out that the Archean have the history and origin, independent of bacteria, and also a set of distinctive features which separate them from other kingdoms.
The first possible fossils which it is possible to carry the Archean to the kingdom belong to 3.5 billion years ago, but have no expressed features allowing to rank precisely them as this kingdom. Some scientific publications tell about existence of remains the Archean in breeds which age is 2.7 billion years, but these data force many scientists to doubt. In the western part of Greenland, more than 3.8 billion years were found age in sedimentary rocks remains of the lipids which are presumably belonging arkheyam.
Thus, there are reasons to believe that the kingdom the Archean – the most ancient on Earth, but it does not have the exact proof yet.
Kingdom of Bacteria
Bacteria are the monocelled nuclear-free organisms similar in a form and the sizes for the Archean too. But on genes and metabolic ways they differ.
Disputes, such ability arkheyam can form bacteria it is inaccessible – they breed division, budding, fragmentation.
Bacteria, under assumptions of scientists, appeared about 4 billion years ago and can be the most ancient organisms on Earth, in any case, it is one of the first kingdoms in the world. Cyanobacteria which waste products were found in the stromatolita formed 3.5 billion years ago were the most ancient bacteria. But the exact evidence of existence of these organisms belongs by the time of about 2 billion years ago. Bacteria became the emergence reason in the atmosphere of Earth of oxygen which allowed organisms to develop aerobic breath though as a result anaerobic bacteria almost completely died out.