Evolution of Hominidae Earliest Hominids

Early Bipedalism Don Johanson…Afar Depression of N. Ethiopia...Lucy, 1974, Australopithecus afarensis....ca. 3.2 MBP…almost 50% Mary Leakey, Tim White…..Laetoli, N. Tanzania, Footprints, 1979, ca. 4.0 MBP Tim White…..Awash area, N. Ethiopia, 1994… Ardipithicus ramidus ("ground man-root”) ca. 4.4 to 4.5 MBP Ahounta Djimdoumalbaye and Michel Brunet….North central Chad, July 2001. Sahelanthropus tchadensis (“Toumai”) .......ca. 6 -7 MBP

Early Bipedalism Australopithecus afarensis (Lucy) Discovered by Donald Johanson at Hadar in Ethiopia. Its age is about 3.2 million years. Lucy was an adult female of about 25 years. About 40% of her skeleton was found, and her pelvis, femur (the upper leg bone) and tibia show her to have been bipedal. She was about 107 cm (3'6") tall (small for her species) and about 28 kg (62 lbs) in weight.

Early Bipedalism Laetoli Footprints (ca. 3.6 MBP). In 1978, fossil footprints of an extinct human ancestor were discovered by Mary Leakey and Tim White. The Laetoli footprints are the most unique evidence of early hominid bipedalism. The prints were impressed in volcanic ash in that location 3.6 million years ago, in sight of the Sadiman volcano 20 kilometers away, whose subsequent ash falls buried them under 30 meters of deposit.

Early Bipedalism Australopithecus afarensis (Dikika baby) Dikika baby, a 3.3 million-year-old infant discovered by Ethiopian paleoanthropologist Zeresenay Alemseged in 2000. The find is the most complete ancient infant and arguably the best fossil of its species, Australopithecus afarensis, ever found.

Early Bipedalism Ardipithicus ramidus Ardipithecus ramidus is one of the earliest hominids found. Ardipithecus ramidus translates literally as "ground man-root" and is thought to be 6 to 7 million years old. Originally it was named as a member of the Australopithecine family, but it was later reclassified. Fragments of 17 different specimens were found including part of a child's mandible, some isolated teeth, fragments of a most of a cranium, and three bones of a left arm of a single individual.

Early Bipedalism Cranium of Sahelanthropus tchadensis (Toumai)...recovered in Chad, July 2001. Dated at about 6-7 MBP. http://www.nature.com/nature/journal/v418/n6894/fig_tab/nature00879_fs.html

Early Bipedalism Australopithicus Many different variations…on average: About 4’ tall 500 cc skull capacity Fully bipedal Gracile (africanus) Robust (robustus)

Early Bipedalism Homo habilis Very similar to late gracile Australopithecines Larger skull capacity More efficient blood circulation to brain (Fig. 6-10) Genus Homo or Australopithecus?

Early Bipedalism Flake Core Blade Lithic Technologies Pebble Tools….. Evidence of Culture? Lithic Technologies Earliest Evidence of Culture Flake Core Blade

(PITHECANTHROPUS ERECTUS) By 1,000,000 Years Ago ... An adaptive radiation had occurred. HOMO ERECTUS (PITHECANTHROPUS ERECTUS) Skull capacity: Range: 750cc - 1100cc Average: 900cc (Note: Australopithecus average Skull capacity 500cc) Associated Culture: Acheulean Early use of fire Hand Axe Culture Hand Axes Base camps Trinil, Java Representative Sites: Zhoukoudian, China “Dragon Bone Hill” Olduvai Gorge, Tanzania Mauer, Germany Ternifine, Tripoli