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The transition from non-life to life has never been observed experimentally, but many proposals have been made for different stages of the process. The study of abiogenesis aims to determine how pre-life chemical reactions gave rise to life under conditions strikingly different from those on Earth today.
In what has occasionally been seen as a prefiguration of a concept of natural selection, Empedocles accepted the spontaneous generation of life, but held that different forms, made up of differing combinations of parts, spontaneously arose as though by trial and error: successful combinations formed the individuals present in the observer's ...
In order to discuss abiological life inside stars, Luis Anchordoqui and Eugene Chudnovsky suggest three postulates which must be satisfied by any reasonable definition of life: [4] The ability to encode information; The ability of information carriers to self-replicate faster than they disintegrate
Spontaneous generation, the first naturalistic theory of abiogenesis, goes back to Aristotle and ancient Greek philosophy, and continued to have support in Western scholarship until the 19th century. [15] The theory held that "lower" animals are generated by decaying organic substances.
A proto-metabolism is a series of linked chemical reactions in a prebiotic environment that preceded and eventually turned into modern metabolism.Combining ongoing research in astrobiology and prebiotic chemistry, work in this area focuses on reconstructing the connections between potential metabolic processes that may have occurred in early Earth conditions. [1]
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 ...
The Bennu organic compounds all have been identified previously in meteorites that have landed on Earth. But there have been lingering questions because these meteorites could have been ...
Sexual reproduction may have increased the rate of evolution. [52] By 1000 Ma First non-marine eukaryotes move onto land. They were photosynthetic and multicellular, indicating that plants evolved much earlier than originally thought. [53] 750 Ma Beginning of animal evolution. [54] [55] 720–630 Ma