Anthro Lecture 10 2.19
- Setting: Pleistocene, Holocene, and Anthropocene
- Pleistocene, or Ice Age, began around 2.5 mya and lasted until 12 kya. During this epoch, ice sheets advanced and retreated, especially in the northern hemisphere
- Using ice core data and other climate proxies, we know that the Pleistocene was characterized largely by climatic variability
- During periods of glaciation, much of the earth's water was trapped in ice sheets meaning that the average global sea levels would have been lower compared to today (Holocene or Anthropocene)
- Rising and falling sea levels had (and have) a major impact on the archaeological record
- During much of the Ice Age, the Americas were cut off from Europe, Asia, & Africa by large ice sheets
- The relatively warm period that we live in today is called the Holocene. It began around 12 kya, and it is during this period that farming and urbanized society appeared
- According to many scientists, we have entered a new geological epoch called the "Anthropocene" where human activities are viewed as being the primary force shaping earth's climate and environment
- How do we arrive at dates for prehistoric periods & archaeological materials?
- Potassium-Argon dating: absolute technique
- Crystals grow in magma chamber. K goes into the crystals
- Volcano erupts. Magma and crystals form tephra/ash
- Over time, K 40 in the crystals radioactively decays to Ar 40
- Around 780,000 yrs ago, earth's magnetic field changed from a reversed state from 2.5 mya to a normal one. Certain rocks that formed or were sufficiently heated before 780 kya were oriented toward the opposite pole
- Paleomagnetism: study of the record of Earth's magnetic field in rocks, sediment, or archaeological materials
- Potassium-Argon dating: absolute technique
- "True humans" may have only appeared about 1.9 mya with the evolution of Homo ergaster who flourished in eastern Africa between abt 1.9 million and 600,000 yrs ago
- Turkana Boy: 1,500,000 yr old Homo ergaster fossil
- Did Homo Ergaster have thick body hair (fur)?
- The gene for dark skin appears 1.2 mya, so probably not as much as a chimp or Australopithecine
- Persistence hunting is a technique where hunters track, wound, and pursue prey until it is exhausted
- Human don't have thick fur, so we're really good at sweating, so we can keep ourselves cool. This gave members of the genus Homo an edge by allowing us to persistence hunt
- Homo erectus was the first hominin to leave Africa. Many consider H. ergaster & H. erectus to be the same species with the only exception being that H. erectus left AfricaWorldbuilding ideas
- Less robust jaws
- Cooking allowed us to process or "digest" food before consuming it, so our jaws didn't need to be as strong
- Evidence of fire possibly made by H. erectus found at Koobi Fora (1.5 mya) in Kenya and Wonderwerk Cave (1 mya) in South Africa
- Central hearth found 350-400 kya
- H. erectus may have controlled fire for warmth and cooking. Sitting around a campfire may have also helped form strong social bonds
- Stone tools getting more and more complex
- Acheulian hand axe: H. erectus's tool of choice
- Many are only a few inches long, but others are over a foot long, weighing 5 lb or more. They are found in Africa, Asia, and Europe
- Aesthetic features
- Acheulian hand axe: H. erectus's tool of choice
- Did H. erectus make art?
- Maybe. Depends on how you define "art"
- 50,000 yr. old shell found in Indonesia, believed to have been engraved by H. erectus
- Potential small statues
- Maybe. Depends on how you define "art"
- Did H. erectus have clothes?
- Cold nighttime temperatures & cooler climates meant that H. erectus probably needed clothes, fire, or both
- Indirect Evidence: 90-120 kya, leather-working bone tools from Morocco
- Less robust jaws