Lecture 22 Flashcards
Homo floresiensis
A small-bodied hominin species found on the island of Flores, Indonesia. Nicknamed “the hobbit” for its short stature (~3 feet tall) and small brain (~420 cc).
Homo naledi
A small-bodied hominin species from South Africa (~4.9 feet tall), with a small brain (465–610 cc) and a mosaic of primitive and modern traits. Dated to ~300,000 years ago.
Liang Bua Cave
Archaeological site in Flores, Indonesia, where H. floresiensis fossils were found, dating to 100,000–60,000 years ago.
Island Dwarfism
Evolutionary phenomenon where large species evolve smaller body sizes when isolated on islands due to limited resources and reduced predation.
Foster’s Island Rule
A principle stating that large animals on islands tend to become smaller (dwarfism), and small animals tend to become larger (gigantism), in response to ecological pressures.
Bifurcated Hypotheses
Two main ideas for H. floresiensis’s small size: (1) they were pathological modern humans (e.g., microcephaly), or (2) they were a distinct species affected by island dwarfism.
Microcephaly Hypothesis
A rejected hypothesis suggesting H. floresiensis had abnormal small stature and brain size due to a developmental disorder.
Insular Gigantism
Evolutionary increase in size of small animals on islands (e.g., giant rats, Komodo dragons on Flores).
Mata Menge & Wolo Sege
Fossil sites on Flores where stone tools dated to 1 million years ago were discovered, suggesting long-term hominin presence.
Dinaledi Chamber
The cave system in South Africa where H. naledi fossils were found deep underground in 2013, requiring tight squeezes to access.
Deliberate Burial Hypothesis
A debated claim that H. naledi intentionally deposited their dead, based on context and positioning of fossils in the Dinaledi cave.
Mosaic Evolution
The idea that different traits evolve at different rates, leading to species with both ancestral and derived characteristics—seen in H. naledi.
Cranial Capacity
The volume of the braincase; used to estimate brain size. H. floresiensis had ~420 cc; H. naledi had 465–610 cc.
Handaxe
Acheulean stone tool shaped like a teardrop; not directly associated with either species but common in earlier Homo.
No DNA Evidence
Modern pygmy humans on Flores do not carry DNA from H. floresiensis, indicating their short stature evolved independently.
Refit Sequence
The reconstruction of flake removals in tool production—used to assess cognitive complexity (relevant in debates about H. naledi’s intelligence).
Unreviewed Claims
The idea that extraordinary claims (like H. naledi art or burials) require peer-reviewed evidence—reminder from Carl Sagan: “Extraordinary claims require extraordinary evidence.”
