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Evolution of cells refers to the evolutionary origin and subsequent evolutionary development of cells. Cells first emerged at least 3.8 billion years ago [1][2][3] approximately 750 million years after Earth was formed. [4]
The cell had a lipid bilayer; it possessed the genetic code and ribosomes which translated from DNA or RNA to proteins. The LUCA probably existed at latest 3.6 billion years ago, and possibly as early as 4.3 billion years ago [2] or earlier. The nature of this point or stage of divergence remains a topic of research.
The first known mass extinction was the Great Oxidation Event 2.4 billion years ago, which killed most of the planet's obligate anaerobes. Researchers have identified five other major extinction events in Earth's history, with estimated losses below: [11] End Ordovician: 440 million years ago, 86% of all species lost, including graptolites
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. [36] [37] The oldest evidence of life is indirect in the form of isotopic ...
However, the cells found within these sedimentary rock—some stretching back some 3.8 billion years—don’t support this assumption. Instead, these ancient microfossils, which have been found ...
The first universal common ancestor (FUCA) is a proposed non-cellular entity that was the earliest organism with a genetic code capable of biological translation of RNA molecules into peptides to produce proteins. [1][2] Its descendents include the last universal common ancestor (LUCA) and every modern cell. [1][3] FUCA would also be the ...
After the LECA, some 2 billion years ago, the eukaryotes diversified into a crown group, which gave rise to animals, plants, fungi, and protists. Eukaryogenesis, the process which created the eukaryotic cell and lineage, is a milestone in the evolution of life, since eukaryotes include all complex cells and almost all multicellular organisms.
Although the LUCA lived over 4 billion years ago (4 Gya), researchers believe it was far from the first form of life. Earlier cells might have had a leaky membrane and been powered by a naturally occurring proton gradient near a deep-sea white smoker hydrothermal vent. Earth remains the only place in the universe known to harbor life.