Chapter 5 is the turning point of this book in more than one way. It is the halfway mark; Chapter 5 measures 100,000 years, and Chapter 10 measures 100,000 times again as long as that. More materially, this was the period when our species stepped up from the animal kingdom and became a spiritual being. We are ready to pivot from the biological evolution of the human body to the progression of human accomplishments and products of the mind.
This chapter takes place entirely within the Pleistocene Epoch. At this scale, we are now able to discern individual glacial and interglacial periods. Geologists number them as Marine Isotope Stages (MIS) in reverse chronological order. 1 The present interglacial (Ch. 4) is MIS 1 and the most recent glacial period was MIS 2. As this pattern continues, all preceding interglacials (green on the timeline below) have odd numbers and the glacials (white) are even. The timeline reveals unusually rapid climate fluctuations in this chapter. MIS 3 was a minor interglacial, so the last cycle similar to today’s climate was MIS 5, particularly the subcycle called MIS 5e, about 120 TYA. 1
For archaeologists, Ch. 5 is pretty well concordant with the Middle Paleolithic (Eurasia) or Middle Stone Age (Africa). The number of stone age industries increases in the more recent past. These industries differ by region and overlap in time, so they do not lend themselves well to a timeline. The Middle Stone Age in general is characterized by more refined knapping techniques than the Lower Stone Age. The most advanced “modern” human behavior characterizes the Upper Stone Age after about 50 TYA.
At long last, it’s time to introduce ourselves to Homo sapiens, aka modern humans. In Chapter 5, our species literally stole the stage. Homo sapiens began to take form 300 TYA, and by 30 TYA it was the only surviving human species. Section II details the appearance of modern humans and the extinction of the rest of the Homo genus.
The rest of the chapter discusses the qualities that make Homo sapiens a unique species. Section III describes modern human anatomy and genetics. Geneticists divide the human species not into “races” but haplogroups, which are defined by migratory patterns of the last 100,000 years. Section IV is about behavioral modernism, which probably matured with spoken language. The human brain, which developed the capability for speech and other symbolic and abstract thought, also gave us a spiritual instinct. For the first time, humans saw themselves reflected in the world around them, a worldview that would eventually be organized into the earliest religions.
Continue to Section 5.II: Hello, Modern Humans; Goodbye, Early Humans
- L. Bruce Railsback et al., “An optimized scheme of lettered marine isotope substages for the last 1.0 million years, and the climatostratigraphic nature of isotope stages and substages”, (2015) Quaternary Science Reviews 111, 94-106, https://doi.org/10.1016/j.quascirev.2015.01.012 (accessed and saved 7/15/18). ↩
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