Thought I'd start this thread from a question posed by Carl2 …
So a rather strange question when life first began did the animals or the plants start first, was there ever an excess of oxygen and lack of enough carbon dioxide?
There are several orders of life (
the top classification) and it can be ambiguous what is alive (virus' etc.)
If gets more interesting in the domains of life, which are
Archaea,
Bacteria and
Eukaryote.
All plants and animals are eukaryote life and are much further down the evolutionary tree than archaea and bacteria.
The earliest life was about 4 billion years ago, oxygen started building up about 3.5 billion years ago, the
great oxygenation event happened about 2.45 billion years ago, eukaryote life evolved about 2.1 billion years ago, multi cellular life about 1.6 billion years ago,
plants about 850 million years ago, animals trace back to the
Cambrian explosion about 635 million years ago.
So, atmospheric oxygen is due to life but beats plants by about 1-2 billion years and animals came after plants but are the same domain of life. After that you get to
kingdoms of life.
