Becoming Human: A Timeline of Our Evolution
You are on the second floor of the Walton Center for Planetary Health, in the offices of the Institute of Human Origins. This display is part of three large displays in the Marston Human Origins Education Gallery.
This is a large wall display that features a timeline of human evolution from seven million years ago to present in three horizontal sections—Changing Ancestral Species, Biological and Technological Changes, and Changing Environments.
The timeline is also sectioned vertically from left to right beginning with 7 million years ago, 6 million years ago, five million years ago, 4 million years ago, 3 million years ago, 2 million years ago, one million years ago, 500,000 years ago, 250,000 years ago, 100,000 years ago to present time.
Reading top to bottom, the timeline is meant to convey information about what ancestral species to humans were living at a point in time, with what biological and technological changes were occurring, and then what environmental changes were occurring that may have forced adaptations or changes in the species living at a point in time.
The top section, "Changing Ancestral Species," includes images of skulls and full skeletons example species of the following horizontally across the timeline:
Basal hominins 7–4.3 million years ago
Generalized australopiths 4.3–1.98 million years ago
Early Homo 2.8–1.65 million years ago
Robust australopiths 2.7–1.0 million years ago
Premodern Homo 1.8 million years ago–300,000 years ago
Neandertals 430,000–40,000 years ago
Anatomically modern humans 300,000 years ago–present
The middle section, "Biological and Technological Changes," includes the following images and text:
1. Human–chimpanzee split 8–7 Ma (Ma refers to "million years ago" and will be used instead of repeating "million years ago" each time); image is a species diagram of the primate order from lemurs to humans
2. Earliest evidence for the emergence of bipedalism 7–6 Ma; image is chimpanzees walking quadripedally and bipedally
3. Loss of large honing canine teeth 7–6 Ma; image of the skull of Sahelanthropus tchadensis
4. Evidence for facultative bipedalism 4.4 Ma; image is illustration of hominins climbing on a tree trunk and standing bipedally
5. Dietary expansions/shifts 3.6 Ma; image is two different types of plant material—one with seeds like wheat brass and one like bamboo
6. Multiple contemporareous species 3.5–3.3 Ma; image is of three skulls—A. afarensis, A. deyiremeda, K. platyops
7. Earliest evidence of habitual bipedalism 3.9 Ma; image is of "walking" Lucy skeleton (3 images as if it were walking of Australopithecus afarensis
8.Lucy! 3.2 Ma; image is the skeleton of Australopithecus afarensis, popularly known as "Lucy," on a red background
9. Hominin with opposable big toe 3.4 Ma; images of drawing of a hominin foot with some bones drawn in
10. Earliest evidence of stone tool use 3.4–3.3 Ma; image is of a rock/stone tool on a dirt background
11. Emergence of the robust australopiths—New dental adaptations to hard/tough diets Around 2.7 Ma; image of a Robust australopith skull
12. Earliest evidence for the emergence of the genus Homo 2.8 Ma; image is of two hands holding a partial jawbone
13. Emergence of Oldowan tools 2.6 Ma; image is of a stone tool/rock against a black background
14. Initial increase in brain size 2 Ma; image is the illustration outline of three different hominins with head and brain illustrations under each one, showing progressively larger crania
15. First migration out of Africa 1.8 Ma; image is of a map of the northern part of Africa, lower Europe, Middle East, and Asia with red lines and arrows showing migration patterns
16. Earliest Acheulean tools 1.7 Ma; image is of a large stone handaxe again a white background
17 Beginning of dental size reduction and increase in brain size 1.8 Ma; image is a skull of Homo habilis
18. Australopiths and Homo sharing the landscape 2.8 Ma–800 Ka (Ka is the abbreviation for thousand years ago); image is an African savannah with three hominins along with antelope
19. Split of Neandertal and Denisovans from the human branch 804 Ka; image is a Neandertal and Denisovan skull
20. Evidence for controlled fire use 800 Ka; image is an excavated side of a cave wall with orange flags showing a dark layer where a fire once was
21. Earliest known hafted hunting technology; image shows three large stone blades mounted onto wooden sticks
22. Earliest Neandertals 430 Ka; image is a Neandertal skull
23. Earliest spears; image is four stone tool blades
24. Earliest modern humans in Africa 300 Ka; image is an illustration of the outline of a hunter against a cave opening and ocean background
25. Beginning of slow human growth and extended development 400–300 Ka; image is of five skeletons from infant size progressively larger to adult size
26. Flake-based projectile points and blade technology 300 Ka; image is of two stone tools—small blades mounted on the end of sticks
27. Coastal foraging at Pinnacle Point, South Africa 164 Ka; image is of an estuary along a coastal landscape
28 Heat treatment of raw materials (stone tools and ochre) 162 Ka; image is of seven small stone blades over a fire
29. Symbolic behavior—Mortuary modification of human skeletal remains 160 Ka; image is of a skeleton in the ground as it had been buried
30. Cooking 120 Ka; image is an illustration of a large piece of meat over a fire in a cave-like setting at night
31. Use of ornaments (beads) 110 Ka; image is of eight beads made out of shells with a small hole in each bead
32. Occupation of very high-altitude environments (Denisovans) 100 Ka; image is of a yurt built on a plain with high mountains in the background
33. Beginning of agricultural communities Around 12 Ka; image is an illustration of women and men working in a field harvesting plants with small huts on stilts in the background
34. Bone tool technology and production of leather clothing 120–90 Ka; image is an illustration of a hand with a stone tool scraping a piece of leather
35. Occupation of circumpolar environments (modern humans) 45 Ka; image is of two women in a snowy landscape with a sledge and an animal skin hut behind them
36. Oldest cave art by Neadertals 64 Ka; image is of red markings on a cave wall
37. First evidence of water craft 65 Ka; image is of three boats made from organic material sitting on sand by the oceanside
38. Earliest skeletal evidence of tuberculosis and Chagas' disease 9 Ka; image is an illustration of a human's chest from the neck to just below the armpit with a call out image of a bacteria over the lung
39. Earliest evidence of writing system 3,400 BCE; image is of cuniform writing on a tablet
40. Humans land on the moon July 20,1969; image is an astronaut in a spacesuit standing on the moon.
The bottom section, "Changing Environments," includes the following images and text:
1. Global cooling 8–5 Ma; image is of Earth with a large glacier covering the northern hemisphere
2. Aridity, enhanced seasonality—Loss of forests and savannah expansion 5–3 Ma; image is two images side by side—left image is of a closed forest, right image is one tree on an open savannah
3. Shifts to even more open and arid environments 3–2.5 Ma; image is an open savannah with one main tree and other small shrubs and trees scattered in the background
4. Pleistocene glaciation begins 2.5 Ma; image is an illustration of all continents on the flattened Earth map with some areas of glaciation
5. Intensification of cold glacial/warm interglacial cycles 1.2 Ma–600 Ka; image is of a graph of Earth temperatures across several million years
6. Mount Toba eruption—Largest volcanic eruption in 2 million years creates global winter 74 Ka; image is two images side by side, the image on the left is a volcanic dust explosion, the image on the right is a map of the area of the Indian Ocean showing the location of Mt. Toba and where the volcanic dust traveled to South Africa
7. Younger Dryas 12.8–11.6 Ka; image is of mastadons and other prehistoric animals in a cold, dry landscape
8. Last 200 years—Earth's climate has been getting dangerously warmer; image is of an ocean glacier calving a large piece into the ocean.
In this section, there is additional text—
- Between one million years and 500,000 years that says: Earth's climate remains relatively stable with alternating glacial and interglacial periods.
- Abrupt cooling of the Earth (indicator at around 12,000 years ago)
- Interglacial period 11 Ka to present
The bottom timeline also includes text for the geological epochs:
Miocene Epoch ends (5.3 Ma) Pliocene Epoch begins (5.3 Ma)
Pleistocene Epoch begins (2.58 Ma)
Holocene Epoch begins (11,700 yrs ago)
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