Australopithecus afarensis

Australopithecus afarensis is an extinct hominid. It lived between about 3.85 million years ago and 2.95 million years ago. Its scientific name is abbreviated as A. afarensis.

The species survived for over 900,000 years, which is over four times as long as modern humans have existed. It lived in East Africa, where Ethiopia, Kenya, and Tanzania now are.

A. afarensis is related to Australopithecus africanus, which came a bit later (between 3.03 and 2.04 million years agoHerries A.I.R. et al 2010. Geochronology and palaeoenvironments of the South African early hominin bearing sites: a reply to ‘Wrangham et al., 2009: Shallow-water habitats as sources of fallback foods for hominins’ Am. J. Phys. Anthro. 143, 640–646). However, it may be more closely related to the genus Homo (which includes Homo sapiens, the modern human species).Johanson D.C. & Maitland A.E. 1981. Lucy: the beginning of humankind. St Albans: Granada, 283297. Wood B.A. 1994. Evolution of australopithecines. In Jones S. Martin R. & Pilbeam D. (eds) 2004. The Cambridge encyclopedia of human evolution. 8th ed, Cambridge University Press, 234. 

Australopithecus means ‘southern ape’. The word afarensis is based on the Afar Depression in Ethiopia, where some of the first A. afarensis fossils were found. Together, Australopithecus afarensis means "southern ape from Afar."

A. afarensis fossils proved that human ancestors walked on two feet over three million years ago, before they evolved larger brains. 

 Discoveries 
Scientists have found many A. afarensis fossils, starting in 1939. 

In 1973 in Hadar, Ethiopia, Donald Johanson and his team of paleoanthropologists found a 3.4 million-year-old A. afarensis knee bone. This was the first fossil to show that humanity's ancestors had been bipedal (walking on two legs) for over 3 million years. 

Encouraged by this find, Johanson's team returned to Hadar. Eventually they found hundreds of other A. afarensis fossils, including the most famous: Lucy.

 Lucy 
See the main article: Lucy (Australopithecus)

In 1974 in Ethiopia, Johanson's team found an A. afarensis skeleton that was around 40% complete. They found 47 out of 207 bones, including parts of the arms, legs, spine, ribs, pelvis, lower jaw, and skull fragments. This was one of the most important fossil discoveries in history.

The team nicknamed this skeleton "Lucy." They used this nickname because they repeatedly played the Beatles song Lucy in the Sky with Diamonds in celebration of their discovery.

Lucy was later found to be around 3.2 million years old. She was a full-grown adult, but was only 110 cm (3.6 feet) tall.

 The 'First Family' 
In Hadar, Ethiopia in 1975, paleoanthropologists found a group of A. afarensis fossils from nine adults and four children. All had been buried at once. This fossil group showed evidence that A. afarensis lived in small groups, possibly based on family bonds, similar to other apes.

 Description 
A. afarensis was similar to slightly later Australopithecus africanus. It had a slender build. Its face was apelike. Based on the size of fossil skulls, its brain was about 1/3 the size of the modern human brain. Its arms were long and strong, and its fingers were curved to help it climb trees.

Based on fossil skeletons, scientists can estimate A. africanus's size. Its height ranged from 1 to 1.7 meters (3.3 to 5.6 feet tall). It weighed about 25 to 64 kg (55 to 141 pounds). Females were much shorter and smaller than males.

A. afarensis was bipedal, meaning that it could walk upright. However, it probably still spent a lot of time climbing trees to find food and shelter.

 Diet 
Based on analysis of A. afarensis fossil teeth, the species was omnivorous but mostly ate plant-based things like leaves, seeds, roots, and nuts. Their teeth also show that they ate soft, sugar-rich fruits. They may have sometimes eaten insects and small vertebrates like lizards. Based on their tooth size and shape, they could have eaten hard, brittle foods during seasons when fruit did not grow.

 Related pages 
 Human evolution
 Extinction
 Lucy (Australopithecus)

 References 

Category:Australopithecines
Category:Evolution