How changing levels of iron shaped the evolution of life on Earth — and why alien hunters should take note

I note this in the report. "The initial formative events of geochemistry evolving into biochemistry, life, took place more than 4 billion years ago. And there is an consensus that iron was a pivotal element for this process. The conditions of early Earth were very different to those now. In particular, there was almost no oxygen in the atmosphere, which meant that iron was easily soluble in water as "ferrous iron" (Fe2+). The abundance of nutritious iron in the Earth’s early seas helped life to evolve. However, this "ferrous paradise" was not to last. The Great Oxygenation Event resulted in the appearance of oxygen in the Earth's atmosphere. It occurred from around 2.43 billion years ago. This changed the surface of Earth and caused a profound loss of soluble iron from the upper ocean and surface waters of the planet. A second, more recent "oxygenation event," the Neoproterozoic, occurred between 800 to 500 million years ago. This raised oxygen concentrations yet higher. As a consequence of these two events, oxygen combined with iron and gigatons of oxidized, insoluble, "ferric iron" (Fe3+) dropped out of ocean waters, becoming unavailable to most lifeforms."

Well, I ponder the MMSN and iron abundance that was incorporated into the proto-earth and fully formed earth after the postulated giant impact with Theia to make the Moon. There are iron meteorites in the inventory, stony meteorites, and stony-iron meteorites with different amounts of iron found in them. Then we have to consider the difference in iron content of Earth and the Moon. The MMSN or protoplanetary disk model could start out with some 3,000 earth masses or perhaps 3 million or more earth masses with different dust and gas content initially some 4.5 billion years ago. Somehow nature juggling all of these different variables managed to create a habitable Earth with life abundant on it today via catastrophism in the early solar system and abiogenesis somehow manages the iron content correctly to create life on Earth.

How Gas Clouds Evolve into People is an interesting subject :)