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The age of Earth is about 4.54 billion years; [7] [33] [34] the earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago according to the stromatolite record. [35] Some computer models suggest life began as early as 4.5 billion years ago.
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.
Earth formed in this manner about 4.54 billion years ago (with an uncertainty of 1%) [25] [26] [4] and was largely completed within 10–20 million years. [27] In June 2023, scientists reported evidence that the planet Earth may have formed in just three million years, much faster than the 10−100 million years thought earlier.
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 ...
[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 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.
They may have lived as early as 4.28 Gya (billion years ago), relatively soon after the formation of the oceans 4.41 Gya, not long after the formation of the Earth 4.54 Gya. [ 78 ] Early micro-fossils may have come from a hot world of gases such as methane, ammonia, carbon dioxide, and hydrogen sulfide , toxic to much current life. [ 227 ]
2.4 – 2.3 billion years ago Earliest evidence (from rocks) that oxygen was in the atmosphere 1.2 billion years ago Red and brown algae become structurally more complex than bacteria 0.75 billion years ago Green algae outperform red and brown algae in the strong light of shallow water 0.475 billion years ago First land plants – mosses and ...