Trabajo De Fis

Timeline of evolution

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Visual representation of the history of life on Earth as a spiral

Life on Earth

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Life

Photosynthesis

Eukaryotes

Complex multicellular life

Animals

Land plants

"Dinosaurs"

Mammals

Flowers

?

Formation

of Earth

?

Meteorite bombardment

?

Atmospheric oxygen

?

Ediacara biota

?

Cambrian explosion

?

Modern-looking

humans

Axis scale: millions of years ago.

Dates prior to 1 billion years ago are speculative.

Not to be confused with History of evolutionary thought.

This article is about the evolution of all life on Earth. See also the timeline of human evolution.

For more detailed and comprehensive coverage, see Evolutionary history of life.

This timeline of evolution of life outlines the major events in the development of life on planet Earth since it first originated until the present day. In biology, evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organization, from kingdoms to species, and individual organisms and molecules such as DNA and proteins. The similarities between all present day organisms indicate the presence of a common ancestor from which all known species, living and extinct, have diverged through the process of evolution.

The dates given in this article are estimates based on scientific evidence.

Contents

[hide]

* 1 Basic timeline

* 2 Detailed timeline

o 2.1 Hadean Eon

o 2.2 Archean Eon

o 2.3 Proterozoic Eon

o 2.4 Phanerozoic Eon

+ 2.4.1 Paleozoic Era

+ 2.4.2 Mesozoic Era

+ 2.4.3 Cenozoic Era

* 3 See also

* 4 Further reading

* 5 References

* 6 External links

[edit] Basic timeline

The basic timeline of a 4.5 billion year old Earth, with approximate dates:

* 3.8 billion years of simple cells (prokaryotes),

* 3 billion years of photosynthesis,

* 2 billion years of complex cells (eukaryotes),

* 1 billion years of multicellular life,

* 600 million years of simple animals,

* 570 million years of arthropods (ancestors of insects, arachnids and crustaceans),

* 550 million years of complex animals,

* 500 million years of fish and proto-amphibians,

* 475 million years of land plants,

* 400 million years of insects and seeds,

* 360 million years of amphibians,

* 300 million years of reptiles,

* 200 million years of mammals,

* 150 million years of birds,

* 130 million years of flowers,

* 65 million years since the non-avian dinosaurs died out,

* 2.5 million years since the appearance of the genus Homo,

* 200,000 years of anatomically modern humans,

* 25,000 years since the disappearance of Neanderthal traits from the fossil record.

* 13,000 years since the disappearance of Homo floresiensis from the fossil record.

[edit] Detailed timeline

Ma, ("megaannum") means "million years ago". ka means "thousand years ago" and ya means "years ago"

[edit] Hadean Eon

3800 Ma and earlier.

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