Antiquity of Humanity Basal Hominids Australopithecines and Paranthropus Early Homo Later Homo

Theories of Human Origins Cosmologies –Religious explanations for our origins, ie. Genesis Mayan Origin Myths Scientific explanations –Using Scientific Method to explain origins Evolution Theory of Natural Selection

Taxonomy Scientific nomenclature-developed by Linnaeus. Kingdom, Phylum, Order, Class, Family, Genus, Species. Genus capitalized and italics, species lower case and italics. –Australopithecus afarensis Names generally reflect region where they come from. Fossil species, not biological species.

Basal Hominids (6-4 mya) Sahelanthropus tchadensis Ardipithecus ramidus Australopithecus anamensis Orrorin tugenensis Recent specimens that date to this time period may represent the earliest on the human line, but not a lot of data yet. Most have small brains and were probably bipedal.

Bipedality Evidence Female Gorilla Australopithecus africanus Modern Humans

Pelvis, Femur and Feet- Comparisons

Some Basal Hominid Remains Sahelanthropus tchadensis Ardipithecus ramidus Orrorin tugenensis

Australopithecus afarensis aka “Lucy” (ca mya)

“Lucy” Discovered by Donald Johanson and Tom Gray in 1974 at Hadar in Ethiopia (all specimens E. Africa) 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.

Australopithecus africanus (ca mya) Small cranial capacity ( cc) Small body size Very similar to “Lucy” Found in S. Africa

Australopithecus garhi (2.5 mya) Major specimen is partial cranium with upper jaw. Brain size 450 cc May be ancestral to Homo habilis u/tietjen/Human%20Nat ure%20S%201999/austr alopithecus_garhi.htm

Paranthropus Chronology ( million years ago) Diagnostic Features (large heavy jaws, sagital crest, small brained, bipedal) Species –Paranthropus boisei –Paranthropus robustus –Paranthropus aethiopicus

Paranthropus boisei Paranthropus robustus Paranthropus aethiopicus

Later Human Evolution: Homo habilis (ca mya)

H. habilis finds

Homo habilis Homo habilis is the earliest known species of the genus Homo; that is, the first human species. –It existed from approximately 2.5 to 1.6 million years ago in east Africa. –Only a few fossil remains have been discovered so far, but these specimens exhibit a clear trend toward larger brain size. –H. habilis brains are about 30% larger than those of A. africanus.

Homo habilis A nearly complete skull of H. habilis was discovered in 1972 at Koobi Fora on the shores of Lake Turkana in Kenya. Its age is estimated at 1.8 million years and its brain capacity at 800 cc. Some anthropologists argue that the variations appear to indicate that several separate species of humans existed; other scientists lump all the individuals together in a single species.

Homo habilis Brain size much bigger than Aus. ( ) Teeth smaller, thinner enamel, more parabolic dental arcade. Skulls rounder, less prognathic, jaw muscles reduced. East and South Africa, same time as robusts. Handyman, associated with Pebble choppers (more later).

This reconstructed skull was found in 1972 on the shores of Lake Turkana. Represents the oldest individual human yet discovered.

Homo habilis Age:ca. 1.8 million years Date of Discovery:October 1968 Location:Olduvai Gorge, Tanzania

First Stone Tools: Oldowan Pebble Choppers

Tool Technology Oldowan Pebble Choppers rounded pebbles portions broken to form sharp edge flakes used for butchering

These crude hand axes and stone flakes could have been manufactured as needed or as opportunity arose. The fracture lines of stones create a sharp cutting surface capable of butchering fairly large animals. The photo above right shows a modern anthropologist skinning a calf with a stone tool made just as ancient Homo habilis would have done.

Environment The background of the photo shows the kind of environment in which this earliest-known human species lived--open bush and savannah country in east Africa. This must must have been a very challenging environment, filled with large predators. ?

Behavior Meat eating Home base, food sharing, sexual division of labor. Archaeological evidence –Animal bones and stone tools at sites (Olduvai) –Hunting or Scavenging? –Probably scavenging.

The Homo habilis Debate It was once thought that the evolution of the genus Homo was an example of anagenesis, the continual and gradual change of one parent species into its daughter species in a linear fashion. As the fossil record began to expand and more early human fossils were found dating to the period between 2 million and 1 million years ago, some questions as to the validity of this hypothesis were raised.

Below are two fossils, shown to scale. KNM ER 1470 is to the left, and KNM ER 1813 is to the right. Originally, both were assigned to the species Homo habilis, with ER 1470 thought of as male and the smaller ER 1813 a female in a strongly dimorphic species. However, the anatomies of the two skulls differ considerably.

Differences Homo habilis Height 1.0 metres Physique Relatively long arms Cranial Volume 500 – 650 cc Known Date2.0 – 1.6 million years ago Distribution Eastern & S? Africa Skull form Relatively small face; nose developed Jaws/Teeth Thinner jaw; smaller, narrow molars Homo rudolfensis Ca. 1.5 metres Robust 600 – 800 cc 2.4 – 1.6 million years ago Eastern Africa Larger, flatter face Robust jaw; large narrow molars