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The earliest known fossil of a eukaryote—the term for organisms, from yeast to humans, that have a cell nucleus and usually require oxygen—is about 2 billion years old. The first fossil big enough to be seen without a microscope—the spiral-chained algae Grypania —appeared 1.9 billion years ago.
1 kwi 2017 · Canfield is conservative where discussing oxygen content in the first billion years, describing it as “whiffs of oxygen” before the Great Oxidation Event (GOE).
1 sty 2010 · The Hadean ranges from the formation of the Earth to the first possible evidence for life, the Archean from then until the advent of atmospheric oxygen and the Proterozoic to the explosion of diverse animal forms, about 0.5 BYA.
Today, around 21 percent of Earth's atmosphere is made up of oxygen. But our planet's atmosphere took time to develop to its current breathable state. The earliest mix of gases to form a thick layer around our cooling planet some 4.6 billion years ago wasn't much different to the kind of stuff emitted by volcanoes, such as methane, hydrogen ...
16 sie 2021 · Earth's early oxygenation history has long been expressed in terms of two fundamental steps: the Great Oxidation Event (GOE) around 2.4 to 2.3 billion years ago (Ga) and a later rise in ocean-atmosphere oxygen levels between 800 and 600 million years ago (Ma) (Canfield, 2005; Kump, 2008; Lyons et al., 2014).
21 mar 2024 · Earth, a little over four billion years ago: The planet was still in its infancy, coming together just 500 million years prior. There was little to no oxygen. The surface—what little there was—was barren, scorching, and volcanic.
1 mar 2019 · Through numerous studies in this field of research, however, evidence has emerged that there were minor amounts of O2 in small areas of Earth’s ancient shallow oceans before the GOE.
