Australopithecus afarensis

They had a low sloping forehead, a projecting face, and prominent eyebrows. The average height for a male was 4ft 11in and the average height for a female was 3ft 5in. The average weight for a male was 94lbs and the average weight for a female was 64lbs. They had long arms and fingers that were useful when they climbed trees. Since they could live in trees and on the ground it helped them survive as the climate and environment changed (Kimbel, 2009).  Assessing the weathering, size, and shape of Lucy's bones helped scientists conclude that she was an adult woman and an upright walking hominin. A hominin is any member of the Homini tribe, which includes modern humans (Schrein, 2015).

Lucy is one of the first hominids to show thickened enamel and flattened teeth (Phys.Org, 2009). At first, it was assumed Lucy ate brittle/hard food like her ancestors, such as nuts or seeds. Scientists were able to create replicas of Lucy's molars using microwear texture to analyze them. After examining the teeth and comparing them to similar species, evidence on her tooth enamel and microwear texture analysis suggests she might have had a simple diet of foods such as fruits or plants (Phys.Org, 2009). 

Their brain was small, about 1.3% of their body weight. It was ⅓ the size of the modern human brain. The reorganization of their brain may have begun with some enlargement to parts of the cerebral cortex. They had a semi-circular ear canal like apes. Their spinal emerged from the central part of the skull base rather than from the back (Kimbel, 2009).