# Human evolutionary history

> 인간의 진화사

<인간>의 <진화사>

## Major events

13,700 mya

- The <Big bang> - Origin of Universe.

4,567 mya

- Earth forms.

3,700 mya

- First life emerges.

1,200 mya

- [Sexual reproduction](https://wiki.g15e.com/pages/Sexual%20reproduction.txt) evolves.

500 - 450 mya

- First <vertebrates>.

365 ya

- <Fish> evolve <lungs> and walk on land.

248 - 208 mya

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

208 - 65 mya

- Large dinosaurs flourished.

114 mya

- <Placental mammals> evolve.

85 mya

- First <primates> evolve.

65 mya

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

35 mya

- First <apes> evolve.

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>.

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)

2.5 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.

10,000 ya (<Holocene epoch> begins)

## 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

- [Evolutionary psychology (book)](https://wiki.g15e.com/pages/Evolutionary%20psychology%20(book.txt)) 중 "Table 1.1 Milestones in Human Evolutionary History"
- <Origins of the social mind> 중 <Language evolution and human development>
- http://en.wikipedia.org/wiki/Human_evolution