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The age of Earth is about 4.54 billion years; the earliest undisputed evidence of life on Earth dates from at least 3.5 billion years ago according to the stromatolite record. Some computer models suggest life began as early as 4.5 billion years ago. The oldest evidence of life is indirect in the form of isotopic fractionation.
Sep 19, 2022 · Learn about the mysteries and theories of how life emerged on our planet, from the Miller-Urey experiment to the role of water and carbon. Explore the possible scenarios of where and when life began, and what ingredients and conditions were involved.
Mar 1, 2017 · Earth is about 4.5 billion years old, but the oldest rocks still in existence date back to just 4 billion years ago. Not long after that rock record begins, tantalizing evidence of life emerges:...
- Simple organic molecules were formed. Simple organic molecules, similar to the nucleotide shown below, are the building blocks of life and must have been involved in its origin.
- Replicating molecules evolved and began to undergo natural selection. All living things reproduce, copying their genetic material and passing it on to their offspring.
- Replicating molecules became enclosed within a cell membrane. The evolution of a membrane surrounding the genetic material provided two huge advantages: the products of the genetic material could be kept close by and the internal environment of this proto-cell could be different than the external environment.
- Some cells began to evolve modern metabolic processes and out-competed those with older forms of metabolism. Up until this point, life had probably relied on RNA for most jobs (as described in Step 2 above).
Timeline of the evolutionary history of life. Not to be confused with History of evolutionary thought. This article is about the evolution of all life on Earth. For more detailed and comprehensive coverage, see History of life. Earth formed. Earliest water. LUCA. Earliest fossils. LHB meteorites. Earliest oxygen. Pongola glaciation.
Oct 19, 2015 · So far, geologists have uncovered possible traces of life as far back as 3.8 billion years. Now, a controversial new study presents potential evidence that life arose 300 million years before that, during the mysterious period following Earth's formation.
History of life. The history of life on Earth traces the processes by which living and fossil organisms evolved, from the earliest emergence of life to present day.
