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The theory of panspermia speculates that life on Earth may have come from biological matter carried by space dust [92] or meteorites. [93] While current geochemical evidence dates the origin of life to possibly as early as 4.1 Ga, and fossil evidence shows life at 3.5 Ga, some researchers speculate that life may have started nearly 4.5 billion ...
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 ...
Evolutionary biology is the subfield of biology that studies the evolutionary processes (natural selection, common descent, speciation) that produced the diversity of life on Earth. It is also defined as the study of the history of life forms on Earth. Evolution holds that all species are related and gradually change over generations. [1]
Many modern theories of the origin of life still take Oparin's ideas as a starting point. About this time, Haldane suggested that the Earth's prebiotic oceans (quite different from their modern counterparts) would have formed a "hot dilute soup" in which organic compounds could have formed.
Darwin published his theory of evolution by natural selection in On the Origin of Species in 1859. [18] His theory means that all life, including humanity, is a product of continuing natural processes. The implication that all life on Earth has a common ancestor has been met with objections from some religious groups.
Artist's conception of Hadean Eon Earth, when it was much hotter and inhospitable to all forms of life. The first eon in Earth's history, the Hadean, begins with the Earth's formation and is followed by the Archean eon at 3.8 Ga. [2]: 145 The oldest rocks found on Earth date to about 4.0 Ga, and the oldest detrital zircon crystals in rocks to ...
The history of paleontology traces the history of the effort to understand the history of life on Earth by studying the fossil record left behind by living organisms. Since it is concerned with understanding living organisms of the past, paleontology can be considered to be a field of biology, but its historical development has been closely tied to geology and the effort to understand the ...