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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 .
Bacteria are prokaryotic microorganisms that can either have a bacilli, spirilli, or cocci shape and measure between 0.5-20 micrometers. They were one of the first living cells to evolve [9] and have spread to inhabit a variety of different habitats including hydrothermal vents, glacial rocks, and other organisms.
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 ...
[4] [5] Charles Darwin more famously proposed the theory of universal common descent through an evolutionary process in his book On the Origin of Species in 1859: "Therefore I should infer from analogy that probably all the organic beings which have ever lived on this earth have descended from some one primordial form, into which life was first ...
c. 190 Ma – Pliosaurs evolve, along with many groups of primitive sea invertebrates. c. 180 Ma – Pangaea splits into two major continents: Laurasia in the north and Gondwana in the south. c. 176 Ma – First stegosaurs. c. 170 Ma – First salamanders and newts evolve. Cynodonts go extinct. c. 165 Ma – First rays and glycymeridid bivalves.
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. The process is widely agreed to have involved symbiogenesis , in which an archeon and a bacterium came together to create the first eukaryotic ...
Evolutionists through the mid-20th century predominantly studied animals, and to a lesser degree plants, and the processes they discovered were placed front and center in evolution's overarching ...
Edward Hitchcock's fold-out paleontological chart in his 1840 Elementary Geology. Although tree-like diagrams have long been used to organise knowledge, and although branching diagrams known as claves ("keys") were omnipresent in eighteenth-century natural history, it appears that the earliest tree diagram of natural order was the 1801 "Arbre botanique" (Botanical Tree) of the French ...