300 - 400 pgs
Hominins of the Later Pleistocene (300 ka to 50 ka)
The Emergence of New Tool Technologies
Around 300,000 years ago (ka), hominins in Africa transitioned to a new stone tool kit.
Hand axes became significantly less common and were superseded by:
Carefully crafted flake tools.
Oldowan flake tools were previously struck from cobble cores and varied in shape and size, while later Pleistocene hominins produced:
Large, symmetric, and regular flakes through more sophisticated techniques.
Levallois Technique
Named after a suburb in Paris where such tools were first identified, the Levallois technique involves three main steps:
Core Preparation: The knapper prepares a core with a precisely shaped convex surface.
Striking Platform Creation: A striking platform is made at one end of the core.
Flake Removal: The knapper strikes the platform to knock off a flake, its shape determined by the original form of the core.
Skilled knappers can produce various tools by changing the form of the original core:
Tools made this way are classified as Mode 3 technology. (Discussed in more detail in Chapter 11.)
Microscopic Analyses and Innovations
Microscopic wear patterns on tools from this period indicate that some tools were hafted (attached to a handle).
Hafting significantly improves the force application when using tools, as illustrated with the example of using a hammer with or without a handle.
Homo heidelbergensis likely hafted pointed flakes onto wooden handles to create effective stone-tipped spears, which marked a major advancement for large-game hunting in this era.
Population and Fossil Discovery in East Asia
H. heidelbergensis appeared in eastern Asia and potentially coexisted with H. erectus during the second half of the Middle Pleistocene.
Prior to middle Pleistocene, H. erectus was the sole hominin in eastern Asia.
Larger-brained hominins with more rounded skull features emerged around 200 ka.
The most well-preserved and dated fossil comes from the Jinniushan site in northern China, comprising a cranium and associated bones.
Similarities with Early H. Heidelbergensis
This cranium exhibits features such as:
A larger braincase (~1,300 cc).
A more rounded skull.
Prominent browridges shared with other early H. heidelbergensis fossils from Africa and Europe.
Additional similar fossils have been located in Dali (northern China) and Maba (southern China), likely being somewhat younger than the Yingkou specimen and associated with Oldowan-type tools.
Debates on Migration
The origins of these fossils raise questions about whether these hominins were immigrants from the west or products of convergent evolution in eastern Asia.
Hominins in Southeast Asia and Island Geography
Hominins displaying characteristics of H. heidelbergensis reached eastern Asia later than in western Eurasia.
In the archaeological record, Homo floresiensis, a small-brained hominin, inhabited Flores island during the Upper Pleistocene.
A significant discovery in 2004 uncovered remains of 9-14 individuals at Liang Bua cave on Flores, including a complete skull and much of the skeleton.
Island Isolation and Unique Fauna
Flores, part of Wallacea, had many small islands between Asia and Australia, which became isolated even at low sea levels.
Unique creatures such as a dwarf elephant and large monitor lizards thrived alongside Homo floresiensis, which stood about 1 m (3 ft) tall.
Physical Characteristics of H. Floresiensis
The skull of specimens labeled LB1 is quite small and resembles early Homo features, with a brain size comparing to that of australopiths.
A significant surprise in the discovery is their age, with most fossils dating between 100 ka and 60 ka.
Researchers speculated regarding their origins, contemplating whether these individuals descended from early Homo habilis or H. erectus that became isolated on Flores.
Discussion of Dwarfism
Their small stature is hypothesized to be evolutionary dwarfism due to isolation on the islands, where reduced body size might be favored by natural selection in limited environments.
Contradictory views suggest these individuals might be modern humans suffering a pathological condition leading to smaller body sizes, referencing conditions like Laron syndrome associated with impaired growth hormone sensitivity.
New Findings from Mata Menge
In 2014, a site named Mata Menge revealed fragments of a hominin mandible and several teeth from at least three individuals, dated to about 700 ka and smaller than those found at Liang Bua.
Archaeological artifacts and tools found at Mata Menge date back to 840 ka to 700 ka and include Oldowan-type tools similar to those at Liang Bua, indicating little technological evolution over time.
Hominins of New Discoveries: Homo luzonensis
Another notable fossil discovery was Homo luzonensis found on Luzon Island, Philippines, dated to between 60 ka and 50 ka.
Fossil remains comprise an incomplete femur, finger and toe bones, and numerous teeth, displaying a mix of ancestral and derived features, including small teeth and overall shapes resembling H. erectus, but finger and toe bones resembling australopiths.
Climate Change and Hominin Adaptation
The last warm interglacial period from 130 ka to 105 ka was followed by cooling, significantly influencing hominin distributions and survival.
Global climate fluctuations have been documented through oxygen isotope ratios from deep Greenland ice cores, indicating:
Warmer periods saw extended habitats for species typically confined to basic geographic limits.
Example: Hippo remains found beneath Central London highlight how species’ ranges were broader in past warm interglacial intervals.
Ice Age and Ecological Transformations
Beginning about 75 ka, global cooling initiated. Resulting significant shifts in climate during later glacial periods resulted in most of northern Europe and Canada being covered in glaciers.
Geographic connections between continents altered substantially, with notable examples such as Bering land bridge connecting Asia and North America, as well as the emergence of plateau landmasses in Southeast Asia.
Post-cooling, Eurasia turned frigid and dominated by vast grasslands that supported megafauna like woolly mammoths, woolly rhinoceroses, reindeer, aurochs, and horses, exacerbated by the major glaciation that reshaped the habitats hominins occupied.
Evolutionary Divergence in H. Heidelbergensis
The morphology of H. heidelbergensis diverged in representation across western Eurasia during the Middle Pleistocene, observable in a notable fossil site, Sima de los Huesos in Spain, dating to approximately 434 ka.
This cave provided a rich fossil assemblage, comprising 2,000 bones from at least 24 individuals. Key characteristics include:
Derived features not observed in African contemporaries, such as double-arched browridges.
Cranial capacity reaching 1,390 cc, aligning closely with modern human averages.
Evidence of Neanderthal Morphology
The Neanderthals, who persisted from around 127 ka to 30 ka, initially identified in 1856, established a unique branch within the human family tree.
Increasingly studied due to abundant fossil findings, Neanderthals possess several distinct morphological features, including:
Larger brains than H. heidelbergensis, typically ranging from 1,245 to 1,740 cc (average ~1,520 cc).
Long and low skull shape with rounded nuchal region, pronounced browridges, and notably robust facial structures.
Dental Features and Diet Examination
Neanderthal dentition reveals smaller molars but heavily worn front teeth, showing adaptions for potential tool use in food processing.
Evidence suggests they were not just scavengers but proficient hunters with a varied diet including large herbivores, interpreted through isotopic analyses of nitrogen, which highlighted significant levels of meat consumption.
Dental calculus revealing phytoliths and starch grains suggests they also incorporated vegetation into their diet.
Artifact Discoveries Reflecting Social Structure
Findings of stone tools including Mode 3 (Mousterian industry) provide indications of Neanderthal life revolving around resource acquisition and toolmaking technologies.
Evidence of extensive hunting practices, for example, assemblages dominated by bones of prime adult indica mammal species like bison suggest organized hunting strategies rather than opportunistic scavenging.
Cultural Behavior Indications
Neanderthal indications of symbolic behavior are still debated, with discoveries such as potential adornments and burial practices bringing attention to their cognitive capacities.
Sites like Shanidar Cave showing fossil remains alongside flowering plant pollen indicate possibilities of ceremonial behavior in funerary practices, though newer analyses have challenged previous interpretations regarding burial customs.
Caregiving Evidence Among Neanderthals
Skeletal analysis indicates many Neanderthals suffered from serious injuries or illnesses, suggesting a community structure capable of caregiving may have existed, as they often lacked the strength to forage independently.
Evolutionary Relationships with DNA Evidence
Molecular advancements have permitted DNA extraction from Neanderthal fossils allowing significant insights into human evolution, with analyses revealing that Neanderthals were genetically distinct yet closely relatable to modern humans.
A genetic distance tree illustrates evolutionary lineages underpinning common ancestors linking Neanderthals, Denisovans, and modern human groups, providing them both distinct genetic paths while showcasing shared roots.
Expanding Understanding of Language Origins
The origins of language continue to be elusive; however, explorations into anatomical structures suggest evolutionary adaptations in humans related to speech.
The existence of the FOXP2 gene, important for language processing, in Neanderthal DNA indicates potential for similar communication skills, though it is uncertain whether they possessed fully developed linguistic capabilities.