Lecture 14: Early Hominins I

These flashcards cover the key concepts and features related to early hominins as discussed in Lecture 14.

What defines a hominin?

A hominin is a group that includes all species more closely related to Homo sapiens than to any living great ape.

What are some uniquely human features?

Some uniquely human features include an extremely large brain, anatomical features associated with bipedalism, very small canines, relatively flat faces, the ability to modify raw materials into recognizable tool types, a chin, and the ability to learn and invent language.

What are the two possible scenarios for human evolution?

Brain first, where the big brain evolved first, or bipedalism first, where walking on hind limbs evolved first, leading to tool use and brain expansion.

What are the three clusters of early hominins?

The three clusters of early hominins are:

• Pre-australopiths (7-4.4 mya, e.g., Ardipithecus ramidus),

• earlier primitive australopiths (4.2-3.0 mya, e.g., Australopithecus afarensis), and

• later derived australopiths (2.5-1.0 mya, e.g., Paranthropus spp.).

What is the significance of Sahelanthropus tchadensis?

Sahelanthropus tchadensis is considered the oldest hominin, lived 6-7 million years ago, with derived traits that include an intermediate position of the foramen magnum, a smaller face, and relatively small canines.

What is taphonomy?

Taphonomy is the study of all the events from an organism’s death to its discovery as a fossil.

What are the key characteristics of Ardipithecus ramidus?

Key characteristics include a chimp-sized brain, an anteriorly positioned foramen magnum suitable for bipedalism, and a short, broad pelvis.

What key features distinguish Australopithecus afarensis from Ardipithecus ramidus?

Australopithecus afarensis is characterized by a chimp-sized brain, smaller canines than Ardipithecus ramidus, and a dental arcade that is a rounded rectangle.

What are robust australopithecines known for?

Robust australopithecines, including Paranthropus spp., are adapted for heavy chewing, featuring a large sagittal crest and massive post-canine teeth.

What is a unique feature of Paranthropus boisei?

Paranthropus boisei is the most robust species of Australopithecus, known for its larger cranial capacity and massive chewing apparatus.