Homo Migrations and Variability

Dmanisi Hominins

  • Cranial characteristics are typical of Homo erectus/ergaster but with a small cranial volume.
  • Generally smaller stature.
  • Size variation: Unresolved issue of sexual dimorphism or two separate species.
  • Proposed classifications: Homo erectus georgicus or Homo georgicus.
  • Possible descendant of an earlier hominin, like Homo habilis.

Homo erectus in Indonesia

  • Particularly long and abundant fossil record on Java.
  • Difficulty in establishing precise timelines due to volcanic intrusions affecting sedimentary deposit dating.
  • Sangiran provides the clearest associations between volcanic eruptions and hominin deposits.

Java and Glacial Periods

  • During glacial periods, lower sea levels connected Indonesian islands to the mainland, allowing Homo erectus to walk to Java.

Java Homo erectus Timeline

  • Ngandong: 80,000 or 27,000-50,000 years ago.
  • Mojokerto Child: 1.8 million years ago (mya).
  • Sangiran: 1.7-1.5 mya.

Homo erectus in China

  • Significant sites include Zhoukoudian and Longgupo, with Longgupo dating back to 1.9 mya.
  • Zhoukoudian dates back 800,000-480,000 years ago.

Excavations at Zhoukoudian

  • Excavations led by Thomson-Wadsworth uncovered significant findings at Zhoukoudian.

Zhoukoudian - \"Peking Man\"

  • Dates to approximately 400,000-780,000 years ago.
  • Numerous hominin fossils, possibly representing around 40 individuals (though fragmentary).
  • Originally thought to be a cave habitation site.
  • Some researchers now suggest it was a hyena den, leading to a natural accumulation of hominin material.
  • Possible use of fire.
  • Animal bone evidence suggests scavenging, with cut marks overlying carnivore gnaw marks.

Homo erectus in Europe

  • Late migration possibly due to glaciation.
  • Atapuerca sites date back to 1.2 mya, with minimal skeletal remains.
  • Mode 1 tools are associated with earlier dates, while Mode 2 tools appear only after 500,000 years ago.
  • Possible two separate colonization events.

Homo erectus…Homo antecessor?

  • Gran Dolina at Atapuerca, Spain: 780,000 years ago.
  • Ceprano, Italy.

One Species or Two?

  • Metric analyses suggest a single species hypothesis, though with more variability than modern humans.
  • Non-metric analysis supports two species, except for two African crania that group with Asian forms.
  • \"erectus grade\" concept.
  • Genus Homo left Africa close to 2 mya, coinciding with its diversification.
  • Variation could be attributed to local adaptations and genetic drift.

Erectus Grade Adaptive Shift

  • Shift to exploiting more open and highly variable environments.
  • Biological adaptations:
    • Increase in body size.
    • Increase in brain size.
    • Elongation of hindlimb.
    • Reduction in gut size.
  • Tool technology changes: Acheulean tradition, evidence of butchery and meat eating (small animal hunting & large animal scavenging?).
  • Use of Fire.
  • Geographic expansion to Eurasia.
  • Changes linked to a shift in dietary adaptation: Increased consumption of meat.

Fire in the Plio-Pleistocene

  • When and why did hominins begin to use fire?
  • Distinction between control versus creation of fire.
  • Significance of fire for human evolution.
  • Some argue fire was the spark for human biological and cultural evolution.
  • Cooking hypothesis.

Early Evidence of Fire

  • Koobi Fora, Kenya: 1.6 mya, burned soil and >80 burned bone fragments.
  • Wonderwerk and Swartkrans caves, South Africa: 1 mya, wood ash.

Fire Use Locations

  • Various sites showing early evidence of fire use, including Happisburgh (UK), Beeches Pit (UK), Menez-Dregan (France), Sima de los Huesos (Spain), Schöningen (Germany), Bilzingsleben (Germany), Pirro Nord (Italy), Bolomor Cave (Spain), Zhoukoudian (China), Gesher Benot Ya'aqov (Israel), Qesem Cave (Israel), Gadeb (Ethiopia), Koobi Fora (Kenya), Chesowanja (Kenya), Swartkrans Cave (South Africa), Wonderwerk Cave (South Africa).

Fire and Homo erectus

  • Did Homo erectus bring the knowledge of fire control/creation during their migrations out of Africa?
  • Or was there independent invention/discovery of fire in different regions?
  • Early but ephemeral evidence of fire control in Africa.
  • Consistent use of fire emerges in the Middle Pleistocene.

The Strange Case of Homo floresiensis

  • Found on the Indonesian island of Flores.
  • Nicknamed \"hobbit\" people due to their small size but with similarities to H. erectus and earlier hominins.
  • Dates range from 90,000 to as recently as 13,000 years ago (revised to 100,000-60,000 years ago).
  • Sophisticated stone tools and evidence of hunting stegadon.
  • Unknown how they reached the island.

Homo floresiensis Characteristics

  • Cranial capacity = 417cm3417 cm^3 (less encephalized than H. erectus, within Australopith range).
  • Very small size: 3’ tall, 44 lbs.
  • Cranial characteristics like H. erectus: large brow ridges, sagittal keel, more prognathic, overall shape.
  • Differences in wrist, shoulder, and foot bones, more similar to earlier hominins; primitive limb proportions.

Explanations for Homo floresiensis

  • Pathological condition in modern humans (e.g., microcephaly or Down syndrome): Not supported by scientific analysis.
  • Evolved from an even earlier hominin (H. habilis or Australopith).
  • Insular dwarfism acting on H. erectus.

The Island Effect

  • Small things get big = island gigantism.
  • Big things get small = insular/island dwarfism.
  • Primates are not immune to this effect.

Wallace Line

  • Homo floresiensis crossed the Wallace Line
  • Seafaring inference.
  • Possible Language?

Hominin Occupation of Flores

  • H. sapiens believed to be present on Flores by 46,000 years ago.
  • Mata Meng site shows evidence of hominin mandible and tooth remains dating back 700,000 years.

Statistical Studies of Homo floresiensis Phylogeny

  • Mixed results from statistical studies of traits to determine the phylogeny of H. floresiensis.
  • Several studies show cranial capacity clusters with more primitive hominins (allometric studies).
  • Studies on cranial shape and non-metric features tend to cluster with H. erectus (but not all do).
  • Limb proportions fall outside the expected range for all human samples, similar to Australopithecus.
  • Argue et al. (2017) studied cranial, mandibular, dental, and postcranial characteristics of H. floresiensis and other hominins (including modern humans) to test:
    • Shared common ancestor with H. habilis.
    • Descendant of H. erectus.
  • Conclusion:
    • Close relationship with H. erectus is rejected.
    • H. floresiensis either shares a common ancestry with H. habilis or is a sister group to all other Homo species.

Homo luzonensis \"Ubag\"

  • Excavations in 2007 at Callao Cave, Luzon, Philippines, revealed tools and faunal remains with cutmarks.
  • Stegadon presence.
  • 2019: tools and bone remains of hominin teeth and phalanges discovered.
  • Similar to Flores, evidence of occupation by 700,000 years ago.

H. luzonensis Characteristics

  • Small number of remains but phenotypically very similar to H. floresiensis.

Crossing the Huxley Line

  • Homo luzonensis crossed the Huxley Line

Paleoproteomics – Protein Analysis

  • Proteomics: the study of the proteins that get expressed in an organism.
  • Proteins:
    • Strings of amino acids produced within cells and folded to form proteins.
    • All structural components of the body are formed of proteins.
    • Enzymes.
    • Hormones.
    • Posttranslational Modifications (PTMs)
  • Paleoproteomics:
    • May last hundreds of thousands or even millions of years.
    • Vs. DNA which only lasts 10s of thousands at most (often less).
    • Used for diet analysis, species identification, and determining phylogenetic relationships (amino acid sequence).

Molecular Homology of Cytochrome C

  • Molecular homology of cytochrome c.

Variations of Enamel Proteins (amelogenin) or in Calculus

  • Homo erectus from Dmanisi, 1.8 mya.
  • Homo antecessor (erectus) from Spain/Atapuerca, 400ka.
  • Paranthropus robustus: 2 mya.