Emergence of Homo sapiens

1
Emergence of Homo sapiens

• Brain size does not distinguish Homo sapiens from
  either archaic Homo sapiens or Neandertals.
• But -- substantial behavioral differences.

2
Novel materials for tools
174-82,000 ya
New designs 21-16,000 ya
3
Appearance of art and ornamentation Indices of
symbolic thinking
Portable art
4
Portable art
32,000 ya
5
Cave art Europe 32,000 ya Africa 26,000 ya
6
(No Transcript)
7
Funeral goods
Earliest burials with grave goods 28,000 ya.
(e.g., Europe) Beads, clothing
8
Origin of modern humans

• Two models
• Each recognizes the dispersal of H. erectus (or
  H. ergaster) from Africa to rest of Old World.
• They differ on what came next.

9
The Models

• 1. Replacement Model
• Modern humans originated only in Africa.
• Dispersed northward into areas occupied by either
  H. erectus or archaic H. sapiens.
• Limited or no interbreeding.
• Replacement of the archaics by anatomically
  modern H. sapiens.
• All geographic variation presently seen in human
  populations is recent.

10

• Replacement model

11
Predictions from the Replacement Model

• Modern humans first seen in Africa
• Later, two anatomically different lineages in
  each Old World region
• Overlap for a brief period of time in each
  region.
• Europe Neandertals and modern humans
• Mainland Asia archaic H .sapiens and modern
  humans
• Southeast Asia possible relictual populations of
  H. erectus and modern humans.
• Genetic record would indicate little sharing of
  gene pools.

12

• 2. Multiregional model
• Only a single human dispersal from Africa (H.
  erectus).
• Anatomically modern human appeared within a short
  time throughout the Old World.
• Result of extensive and prolonged gene flow among
  archaic populations in different regions.
• Alleles underlying anatomically modern humans
  thus moved from one group to another.

13
Multiregional model
14
Predictions from the Multiregional Model

• A single evolving lineage with regional
  variation.
• Should find fossils, with intermediate
  characteristics of ancestors and descendants.
• Regional variation should transition from earlier
  to later populations.
• Genetic evidence should show ancient
  contributions to the modern gene pool.