Fossils of the bipedal primates Ardipithecus, Australopithecus and early Homo species are used to support the 'Out of Africa' hypothesis - English General - NSC Life Sciences - Question 4 - 2016 - Paper 2

The evidence supporting the 'Out of Africa' hypothesis can be categorized into three types: fossil evidence, genetic evidence, and cultural evidence.

Fossil Evidence:

• Fossils of Ardipithecus were found ONLY in Africa, specifically in the Rift Valley, Ethiopia, and South Africa.
• Fossils of Australopithecus were also found ONLY in Africa, across locations like Ethiopia and South Africa.
• The fossils of Homo habilis were ONLY found in Africa.
• The oldest fossils of Homo erectus were discovered in Africa, and the oldest fossils of Homo sapiens were likewise found on the continent.

Genetic Evidence:

• Mitochondrial DNA is inherited only from the maternal line.
• Mutations analyzed in mitochondrial DNA show that the oldest female ancestor was located in Africa, supporting that all humans descended from her.
• The Y chromosome, passed along the paternal line, reflects a similar origin in Africa.

Cultural Evidence:

• The oldest known primitive artifacts, including tools and cutlery, were found in Africa.

The fossils of all three genera indicate that:

• The foramen magnum is located in a more forward position, which is characteristic of bipedal organisms.
• The pelvis structure is wider and shorter than that of non-bipedal primates, providing better support for upright walking.
• The spine's shape is S-shaped, which is an adaptation for bipedal locomotion.