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The earliest evidence for life on Earth includes: 3.8 billion-year-old biogenic hematite in a banded iron formation of the Nuvvuagittuq Greenstone Belt in Canada; [30] graphite in 3.7 billion-year-old metasedimentary rocks in western Greenland; [31] and microbial mat fossils in 3.48 billion-year-old sandstone in Western Australia.
As for life on land, in 2019 scientists reported the discovery of a fossilized fungus, named Ourasphaira giraldae, in the Canadian Arctic, that may have grown on land a billion years ago, well before plants are thought to have been living on land. [100] [101] [102] The earliest life on land may have been bacteria 3.22 billion years ago. [103]
The oldest stromatolites have been dated to approximately 3.5 billion years old. [18] Stromatolites in Barberton have been dated to about 3.3 billion years. Microfossils found in chert extend the Barberton microfossil record back to 3.5 billion years. All three types of microfossil morphologies are found in cherts.
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
Photosynthetic organisms appeared between 3.2 and 2.4 billion years ago and began enriching the atmosphere with oxygen. Life remained mostly small and microscopic until about 580 million years ago, when complex multicellular life arose, developed over time, and culminated in the Cambrian Explosion about 538.8 million years ago. This sudden ...
The evolution of bacteria has progressed over billions of years since the Precambrian time with their first major divergence from the archaeal/eukaryotic lineage roughly 3.2-3.5 billion years ago. [1] [2] This was discovered through gene sequencing of bacterial nucleoids to reconstruct their phylogeny.
[2] [3] It is estimated to have occurred between 3.5 and 2.4 billion years ago during the Archean eon, prior to the Great Oxygenation Event and Huronian glaciation. [ 4 ] Retinal-containing cell membranes exhibit a single light absorption peak centered in the energy-rich green-yellow region of the visible spectrum , but transmit and reflect red ...
The Strelley Pool Chert, also located in the Pilbara Craton, contains stromatolites that may have been created by bacteria 3.4 billion years ago. However, it is possible that these stromatolies are abiogenic and were actually formed through evaporitic precipitation then deposited on the sea floor. [5]