C
cassini
Guest
When I got to the first ‘PROBABLY’ I switched off. Their whole ‘science’ depends on assumptions, but assumptions are not science but a faith, a belief, a hope their atheism depends on.There is more to life that just animals and plants. At the base of the tree of life there are three major groups: bacteria, archea and eukaryotes (the viruses evolved later). The eukaryotes are divided into protists, plants, animals and fungi. Protists are always single celled. Plants and fungi may be single celled or multi celled. Animals (metazoa) are all multi celled.
The first living thing was probably a very simple single celled proto-bacterium. It did need to eat and basically it would have eaten the chemicals in the water around it. Bacteria can process many different chemicals and since life is theorised to have arisen in the chemical soup, then the first life would have started off eating that soup.
No. The early earth had almost zero free oxygen; all early life was anaerobic - it did not need oxygen. Many bacteria today do not need oxygen - they form the smelly stagnant mess at the bottom of ponds. Oxygen only became important after photosynthesis evolved. For much of early life oxygen was a poison, see the Oxygen Catastrophe.
You have been misinformed. Anaerobic bacteria and archea do not need air to breathe, and indeed for the great majority of then oxygen is a poison. Early life did not require oxygen and was entirely anaerobic.
Photosynthesis evolved about a billion years after the origin of life, before that there were no plants. Multi-celled animals evolved about two billion years after plants. Early plants were all single celled algae. Conditions on the early earth were very different to conditions now. Life on the early earth was also very different to life now. You seem to be trying to extrapolate the present back into the past, this is a mistake. The distant past was very different.
The first life was very probably very simple proto-bacteria. Archaea are also single celled and probably evolved from bacteria before the arrival of photosynthesis (and hence oxygen). At this point various single celled organisms were eating raw chemicals and each other. Once photosynthesis evolved algae could start making their own food from carbon dioxide, water and sunlight. Some bacteria/archaea evolved to make use of the oxygen that photosynthesis produced while others retreated to places where there was no oxygen - the ancestors of the modern anaerobes. Later still a bacterium and an archaea merged to form the first single celled eukaryote. All eukaryotes use oxygen; we are eukaryotes and our mitochondria are the descendants of the bacterial part of the merger. Different elements of the current system evolved at different times, each new arrival making use of what was already present and the existing organisms adjusting to take account of the new presence.
rossum