पृथ्वी पर जीवन के अस्तित्व का इतिहास



मूलभूत समयरेखा
पृथ्वी के 

4.6 बिलियन वर्ष इतिहास में जीवन का इतिहास इस प्रकार है-

 पिछले 3.6 बिलियन वर्षों तक, सरल कोशिकाएँ (prokaryotes);
 पिछले 3.4 बिलियन वर्षों तक, स्यानोबैकेटीरिया (cyanobacteria) प्रकाश संश्लेषण करता रहा;
 पिछले 2 बिलियन वर्षों तक, जटिल कोशिकाएँ (eukaryotes);
 for the last 1 billion years, multicellular life;
 पिछले 600 मिलियन वर्षों तक, सरल जन्तु;
 for the last 550 million years, bilaterians, water life forms with a front and a back;
 for the last 500 million years, fish and proto-amphibians;
 for the last 475 million years, land plants;
 for the last 400 million years, insects and seeds;
 for the last 360 million years, amphibians;
 for the last 300 million years, reptiles;
 for the last 200 million years, mammals;
 for the last 150 million years, birds;
 for the last 130 million years, flowers;
 for the last 60 million years, the primates, 
 for the last 20 million years, the family Hominidae (great apes);
 for the last 2.5 million years, the genus Homo (human predecessors);
 for the last 200,000 years, anatomically modern humans.

Periodic extinctions have temporarily reduced diversity, eliminating:
 2.4 billion years ago, many obligate anaerobes, in the oxygen catastrophe;
 252 million years ago, the trilobites, in the Permian–Triassic extinction event;
 66 million years ago, the pterosaurs and nonavian dinosaurs, in the Cretaceous–Paleogene extinction event.
Dates are approximate.

विस्तृत समयरेखा 
In this timeline, Ma (for megaannum) means "million years ago", ka (for kiloannum) means "thousand years ago", and ya means "years ago".

Hadean Eon 

4000 Ma and earlier.

Archean Eon 

4000 Ma – 2500 Ma

Proterozoic Eon 

2500 Ma – 542 Ma

Phanerozoic Eon 

542 Ma – present

The Phanerozoic Eon, literally the "period of well-displayed life", marks the appearance in the fossil record of abundant, shell-forming and/or trace-making organisms. It is subdivided into three eras, the Paleozoic, Mesozoic and Cenozoic, which are divided by major mass extinctions.

पुराजीवी महाकल्प 

542 Ma – 251.0 Ma

मध्यजीवी महाकल्प

नूतनजीवी महाकल्प 

66 Ma – present

ऐतिहासिक विलोपन (Historical extinctions)

इन्हें भी देखें
 भूवैज्ञानिक समय-मान
 पृथ्वी का इतिहास
 कार्बन-१४ द्वारा कालनिर्धारण
 प्राकृतिक इतिहास

पठनीय 
 The Ancestor's Tale by Richard Dawkins, for a list of ancestors common to humans and other living species

सन्दर्भ

बाहरी कड़ियाँ
 Berkeley Evolution
 Evolution Timeline
 Tree of Life Web Project - explore complete phylogenetic tree interactively
 A more compact timeline at the TalkOrigins Archive
 Palaeos - The Trace of Life on Earth
 John Kyrk's Timeline from Big Bang to present
 University of Waikato - Sequence of Plant Evolution
 University of Waikato - Sequence of Animal Evolution
 Graphical Timeline of evolution 
 History of Life on Earth
 Exploring Time from Planck Time to the lifespan of the universe
 Interactive Plant Evolution Timeline - from the University of Cambridge Ensemble Project

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