# Human evolutionary history

> The evolutionary history of humans

The <evolutionary history> of <humans>

## Major events

13,700 mya

- The <Big bang> - Origin of Universe.

4,568 mya

- Earth forms

4,540 mya

- <Hadean eon> begins

4,100 mya

- Possible first signs of life ([Potentially biogenic carbon preserved in a 4.1 billion-year-old zircon](https://pmc.ncbi.nlm.nih.gov/articles/PMC4664351/), 2015 study)

4,031 mya

- The <Hadean eon> ends; the [Archean eon](https://wiki.g15e.com/pages/Archean%20eon.txt) and <Eoarchean era> begin

4,000 - 3,800 mya

- <Prokaryotes> appear

3,600 mya

- The <Eoarchean era> ends; the <Paleoarchean era> begins

3,500 mya

- <Cyanobacteria> appear

3,200 mya

- The <Paleoarchean era> ends; the <Mesoarchean era> begins

2,800 mya

- The <Mesoarchean era> ends; the <Neoarchean era> begins

2,500 - 2,200 mya

- The first organisms to use <oxygen>
- <Great Oxidation Event>

2,500 mya

- The [Archean eon](https://wiki.g15e.com/pages/Archean%20eon.txt) and <Neoarchean era> end; the [Proterozoic eon](https://wiki.g15e.com/pages/Proterozoic%20eon.txt), [Paleoproterozoic era](https://wiki.g15e.com/pages/Paleoproterozoic%20era.txt) and <Siderian period> begin

2,300 mya

- The <Siderian period> ends; the <Rhyacian period> begins

2,200 - 1,800 mya

- <Eukaryotes> appear

2,050 mya

- The <Rhyacian period> ends; the <Orosirian period> begins

1,800 mya

- The <Orosirian period> ends; the <Statherian period> begins

1,600 mya

- The [Paleoproterozoic era](https://wiki.g15e.com/pages/Paleoproterozoic%20era.txt) and <Statherian period> end; the [Mesoproterozoic era](https://wiki.g15e.com/pages/Mesoproterozoic%20era.txt) and <Calymmian period> begin

1,400 mya

- The <Calymmian period> ends; the <Ectasian period> begins

1,200 mya

- The <Ectasian period> ends; the <Stenian period> begins
- <Sexual reproduction> evolves

1,000 mya

- The [Mesoproterozoic era](https://wiki.g15e.com/pages/Mesoproterozoic%20era.txt) and <Stenian period> end; the [Neoproterozoic era](https://wiki.g15e.com/pages/Neoproterozoic%20era.txt) and <Tonian period> begin

720 mya

- The <Tonian period> ends; the <Cryogenian period> begins

635 mya

- The <Cryogenian period> ends; the <Ediacaran period> begins

538.8 mya

- The [Proterozoic eon](https://wiki.g15e.com/pages/Proterozoic%20eon.txt), [Neoproterozoic era](https://wiki.g15e.com/pages/Neoproterozoic%20era.txt) and <Ediacaran period> end; the [Phanerozoic eon](https://wiki.g15e.com/pages/Phanerozoic%20eon.txt), [Paleozoic era](https://wiki.g15e.com/pages/Paleozoic%20era.txt), [Cambrian period](https://wiki.g15e.com/pages/Cambrian%20period.txt) and <Terreneuvian epoch> begin.
- The entire span from Earth's formation up to this point is collectively called the <Precambrian>.
- [Cambrian explosion](https://wiki.g15e.com/pages/Cambrian%20explosion.txt)

521 mya

- The <Terreneuvian epoch> ends; the <Cambrian Series 2> begins

506.5 mya

- The <Cambrian Series 2> ends; the <Furongian epoch> begins

500 - 450 mya

- First <vertebrates>.

486.85 mya

- The [Cambrian period](https://wiki.g15e.com/pages/Cambrian%20period.txt) and <Furongian epoch> end; the [Ordovician period](https://wiki.g15e.com/pages/Ordovician%20period.txt) and <Early Ordovician> begin

471.3 mya

- The <Early Ordovician> ends; the <Middle Ordovician> begins

458.2 mya

- The <Middle Ordovician> ends; the <Late Ordovician> begins

445-444 mya

- <Late Ordovician mass extinction>

443.1 mya

- The [Ordovician period](https://wiki.g15e.com/pages/Ordovician%20period.txt) and <Late Ordovician> end; the [Silurian period](https://wiki.g15e.com/pages/Silurian%20period.txt) and <Llandovery epoch> begin

433.4 mya

- The <Llandovery epoch> ends; the <Wenlock epoch> begins

426.7 mya

- The <Wenlock epoch> ends; the <Ludlow epoch> begins

423.0 mya

- The <Ludlow epoch> ends; the <Pridoli epoch> begins

419.62 mya

- The [Silurian period](https://wiki.g15e.com/pages/Silurian%20period.txt) and <Pridoli epoch> end; the [Devonian period](https://wiki.g15e.com/pages/Devonian%20period.txt) and <Early Devonian> begin

393.47 mya

- The <Early Devonian> ends; the <Middle Devonian> begins

382.7 mya

- The <Middle Devonian> ends; the <Late Devonian> begins

372–359 mya

- <Late Devonian mass extinction>

365 mya

- [Fish](https://wiki.g15e.com/pages/Fish.txt) evolve <lungs> and walk on land.

358.86 mya

- The [Devonian period](https://wiki.g15e.com/pages/Devonian%20period.txt) and <Late Devonian> end; the [Carboniferous period](https://wiki.g15e.com/pages/Carboniferous%20period.txt) and <Early Mississippian> begin

346.7 mya

- The <Early Mississippian> ends; the <Middle Mississippian> begins

330.3 mya

- The <Middle Mississippian> ends; the <Late Mississippian> begins

323.2 mya

- The <Late Mississippian> ends; the <Early Pennsylvanian> begins

315.2 mya

- The <Early Pennsylvanian> ends; the <Middle Pennsylvanian> begins

307.0 mya

- The <Middle Pennsylvanian> ends; the <Late Pennsylvanian> begins

298.9 mya

- The [Carboniferous period](https://wiki.g15e.com/pages/Carboniferous%20period.txt) and <Late Pennsylvanian> end; the [Permian period](https://wiki.g15e.com/pages/Permian%20period.txt) and <Cisuralian epoch> begin

272.95 mya

- The <Cisuralian epoch> ends; the <Guadalupian epoch> begins

259.1 mya

- The <Guadalupian epoch> ends; the <Lopingian epoch> begins

252 mya

- <Permian-Triassic extinction event>

251.9 mya

- The [Paleozoic era](https://wiki.g15e.com/pages/Paleozoic%20era.txt), [Permian period](https://wiki.g15e.com/pages/Permian%20period.txt) and <Lopingian epoch> end; the [Mesozoic era](https://wiki.g15e.com/pages/Mesozoic%20era.txt), [Triassic period](https://wiki.g15e.com/pages/Triassic%20period.txt) and <Early Triassic> begin

248 - 208 mya

- First small <mammals> and <dinosaurs> evolved.

247.2 mya

- The <Early Triassic> ends; the <Middle Triassic> begins

237 mya

- The <Middle Triassic> ends; the <Late Triassic> begins

208 - 65 mya

- Large dinosaurs flourished.

201.4 mya

- The [Triassic period](https://wiki.g15e.com/pages/Triassic%20period.txt) and <Late Triassic> end; the [Jurassic period](https://wiki.g15e.com/pages/Jurassic%20period.txt) and <Early Jurassic> begin

201.3 mya

- <Triassic–Jurassic extinction event>

174.1 mya

- The <Early Jurassic> ends; the <Middle Jurassic> begins

163.5 mya

- The <Middle Jurassic> ends; the <Late Jurassic> begins

143.1 mya

- The [Jurassic period](https://wiki.g15e.com/pages/Jurassic%20period.txt) and <Late Jurassic> end; the <Cretaceous period> and <Early Cretaceous> begin

114 mya

- <Placental mammals> evolve.

100.5 mya

- The <Early Cretaceous> ends; the <Late Cretaceous> begins

85 mya

- First <primates> evolve.

66 mya

- The [Mesozoic era](https://wiki.g15e.com/pages/Mesozoic%20era.txt), <Cretaceous period> and <Late Cretaceous> end; the [Cenozoic era](https://wiki.g15e.com/pages/Cenozoic%20era.txt), <Paleogene period> and <Paleocene epoch> begin
- <Cretaceous–Paleogene extinction event>

65 mya

- <Dinosaurs> go extinct, <mammals> then increase in size and diversity.

56 mya

- The <Paleocene epoch> ends; the <Eocene epoch> begins

35 mya

- First <apes> evolve.

33.9 mya

- The <Eocene epoch> ends; the <Oligocene epoch> begins

23.04 mya

- The <Paleogene period> and <Oligocene epoch> end; the <Neogene period> and <Miocene epoch> begin

10 - 7 mya

- <Africa>'s major tectonic event that led to the [Formation of the Great Rift Valley](https://wiki.g15e.com/pages/Formation%20of%20the%20Great%20Rift%20Valley.txt).

8 - 6 mya

- The divergence of our hominid ancestors from the <Great Apes>.

5.333 mya

- The <Miocene epoch> ends; the <Pliocene epoch> begins

4.4 mya

- Emergence of [Bipedalism](https://wiki.g15e.com/pages/Bipedalism.txt) to avoid competition with monkeys(<Australopithecus anamensis>, <Australopithecus afarensis> - aka <Lucy>)
  - Upright posture and full eye contact provided room for the emergence of the first gestural signals.
  - The forearms can then be used to hold tools and weapons.
  - The move to [Bipedalism](https://wiki.g15e.com/pages/Bipedalism.txt) opened up major cognitive challenges in terms of the control of the hands.

4 mya

- Major reorganization of <Parietal cortex>.
	- Reduction of primary visual striate cortex
	- The enlargement of <Extrastriate parietal cortex>, <Angular gyrus>, and <Supramarginal gyrus>
- Such changes in the <Parietal cortex> support three basic cognitive functions.
    - Processing in the dorsal stream (see <Two-streams hypothesis>) of the visual field is important for representing actions of the other in terms of one's own body image.
    - The association area of parietal maintain a map of the environment for navigation in the new bipedal mode.
    - The <Supramarginal gyrus> is involved in <Face perception>. Expansion of this area would facilitate the development of social patterns and memory for social relations. -> It played a large role during the next period of evolution (social cohesion).

3.5 mya

- The hominids in <East Africa> went through an expansion of their range and a proliferation of species.
    - Tight competition with range contraction leads a set of targeted neural-behavioral adaptations. - the subordination of vocal system to cortical control.
    - Side-effect of the cortical control over vocalization: local forms of communication like those of song-birds.
- How about the <Great apes> in <West Africa>?
    - The different requirements on group size in their arboreal habitat
    - No bipedal gait and its resultant improvements in face-to-face communication.

3 mya

- The <Australopithecus> evolve in savannas of <Africa>.
- A gradual tripling of brain size.
    - Massive changes in the interconnectedness of the <Frontal lobe>s.
    - Changes in the linkage of vocal production to motor and emotional areas.
    - Linkages of the visual areas to motor areas.
    - Expansion of many older areas, including the <Cerebellum>, <Basal ganglion>, and <Thalamus>.
    - (these changes are basis for an ability to produce actions through movement and sounds throught vocalization)

2.58 mya

- The <Neogene period> and <Pliocene epoch> end; the <Quaternary period> and <Pleistocene epoch> begin. The Quaternary is the final period of the [Cenozoic era](https://wiki.g15e.com/pages/Cenozoic%20era.txt) and continues to the present.

2.5 mya

- Earliest stone tools - Oldowan (found in <Ethiopia> and <Kenya>, <Africa>); used to butcher carcasses for <meat> and to extract marrow from bones; linked with <Homo habilis>.

2 mya

- The remarkable expansion of habitat to all of <Africa> and <Eurasia> by <Homo erectus>.
- Brain expansion ran up against the [Bipedalism](https://wiki.g15e.com/pages/Bipedalism.txt), forcing a series of adaptations in female anatomy, parturition, and child rearing.
- New forms of symbolic communication system - the spontaneous interaction of vocalizations, postures, and gestures in specific social and pragmatic contexts.
    - Vocalizations had not yet been systematized. Gestural and postural patterns probably played a more central role.
    - But their iconic and situated nature may have seved as a barrier to abstract systematization.

1.8 mya (the end of the <Pliocene epoch>, and the beginning of the Ealry <Pleistocene epoch>)

- <Homo erectus> had achieved dominance over its hominid competitors.
- The onset of the glaciations of the <Pleistocene epoch>.
- <Homo erectus> spread beyond African <Homo erectus>. The first migration from Africa.

1.6 mya

- First evidence; likely hearths; linked with African <Homo erectus>.

1.5 mya

- Invention of Acheulean hand axe; linked with <Homo ergaster> - tall stature, long limbs.

1.2 mya

- Brain expansion in homo line begins.

1 mya

- Hominids spread to <Europe>.

800,000 ya

- Crude stone tool kit - found in <Spain>, linked with <Homo antecessor>.

780,000 ya (middle <Pleistocene epoch> begins)

600,000 - 400,000 ya

- Long crafted wooden spears and early hearths; linked with <Homo heidelbergensis> found in <Germany>.

500,000 - 100,000 ya

- Period of most rapid brain expansion in Homo line.

300,000 - 50,000 ya

- Gradual evolution of new system that supports a set of phonological contrasts.
    - A major expansion of the parts of the vertebrae that carry nerves for the intercostal muscles. (p384)
    - Loss of the canines.
    - Adaptation of the arytenoids.
    - Bending of the vocal tract.
    - shaping of the musculature of the tongue.

200,000 ya

- The emergence of <Homo sapiens> and <Mitochondrial Eve>.

200,000 - 30,000 ya

- <Neanderthals> flourish in <Europe> and western <Asia>.

126,000 ya

- Late <Pleistocene epoch> begins.

100,000 - 50,000 ya

- Exodus from Africa - second major migration. See also <Out of Africa theory>

70,000 ya

- Near extinction that brought the number of our direct ancestors down to only 10,000 individuals worldwide.

40,000 ya

- Explosion of diverse stone tools, bone tools, blade tools, well-designed fireplaces, elaborate art; found only among <Homo sapiens>, not among <Neanderthal>s.

40,000 - 35,000 ya

- <Homo sapiens> (<Cro-Magnon>) arrive in <Europe>.

30,000 ya

- <Neanderthal>s go extinct.

27,000 ya

- <Homo sapiens> colonize entire planet; all other hominid species are now extinct.

11,700 ya

- The <Pleistocene epoch> ends; the <Holocene epoch> begins
- <Holocene extinction>

## Articles

- 2025-03-18 - [Genetic study reveals hidden chapter in human evolution | University of Cambridge](https://www.cam.ac.uk/research/news/genetic-study-reveals-hidden-chapter-in-human-evolution)
	- Modern humans descended from not one, but at least 2 ancestral populations that drifted apart and later reconnected, long before modern humans spread across the globe.
- 2024-07-12 - [Princeton geneticists are rewriting the narrative of Neanderthals and other ancient humans](https://www.princeton.edu/news/2024/07/12/history-contact-princeton-geneticists-are-rewriting-narrative-neanderthals-and)

## See also

- "Table 1.1 Milestones in Human Evolutionary History" in <Evolutionary psychology (book)>
- <Language evolution and human development> in <Origins of the social mind>
- http://en.wikipedia.org/wiki/Human_evolution