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The PAH world hypothesis is a speculative hypothesis that proposes that polycyclic aromatic hydrocarbons (PAHs), known to be abundant in the universe, [177] [178] [179] including in comets, [180] and assumed to be abundant in the primordial soup of the early Earth, played a major role in the origin of life by mediating the synthesis of RNA ...
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.
The timeline of the evolutionary history of life represents the current scientific theory outlining the major events during the development of life on planet Earth. Dates in this article are consensus estimates based on scientific evidence , mainly fossils .
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 ...
Abiogenesis or biopoiesis is the natural process of life arising from non-living matter such as simple organic compounds. Subcategories This category has the following 4 subcategories, out of 4 total.
The History of Animals contains many accurate eye-witness observations, in particular of the marine biology around the island of Lesbos, such as that the octopus had colour-changing abilities and a sperm-transferring tentacle, that the young of a dogfish grow inside their mother's body, or that the male of a river catfish guards the eggs after ...
The natural history of Earth concerns the development of planet Earth from its formation to the present day. [ 1 ] [ 2 ] Nearly all branches of natural science have contributed to understanding of the main events of Earth's past, characterized by constant geological change and biological evolution .
Evidence of possibly the oldest forms of life on Earth has been found in hydrothermal vent precipitates. [1]The earliest known life forms on Earth may be as old as 4.1 billion years (or Ga) according to biologically fractionated graphite inside a single zircon grain in the Jack Hills range of Australia. [2]