Chapter Study Outline
1. Homo habilis: The First Species of the Genus Homo
a. The Path to Humanness: Bigger Brains, Tool Use, and Adaptive Flexibility
i. First discovered by Louis Leakey at Olduvai Gorge
ii. Change took place 3.0–2.5 mya
iii. Found in Tanzania, Kenya, Ethiopia, Malawi, South Africa
b. Homo habilis and Australopithecus: Similar in Body Plan
i. Immediate ancestor unconfirmed (Tim White suggests A. garhi)
ii. Bigger brain, smaller chewing complex
iii. Body plan similar to that of australopithecines
c. Homo habilis’s Adaptation: Intelligence and Tool Use Become Important
i. Anatomical evidence from the hand bones suggests precision grip.
ii. Tools becoming fundamental to survival, unlike for australopithecines
d. Habitat Changes and Increasing Adaptive Flexibility
i. Spread of warm season grasses and increasing habitat diversity.
ii. Skull and tooth morphology suggest dietary variability in Homo habilis.
iii. Stone tools important for obtaining food resources as well as for processing foods.
2. Homo erectus: Early Homo Goes Global
a. First discovered by Eugène Dubois in Java
b. Fossils date from 1.8–0.3 mya
c. Homo erectus in Africa (1.8–.3 mya)
i. African fossils dated to 1.8–0.3 mya
ii. Nariokotome skeleton
(1) An 80% complete skeleton
(2) Short arms, long legs
(3) Likely a young male
(4) Would have stood 6 feet tall in adulthood
(5) Cranial capacity over 900 cc
iii. Footprints discovered at Ileret and dated to 1.5 mya provide evidence of fully modern walking
iv. Bodo skull
(1) Stone tool marks on the left cheek, eye orbit, and nasal bones
(2) Ritual or cannibalism?
d. Homo erectus in Asia (1.8–.3 mya)
i. Fossils dated to 1.8 mya–0.3 mya
ii. Earliest evidence found in Dmanisi, dated to 1.7 mya
(1)Resemblance to East African Homo erectus
iii. Also found in Indonesia, Sangiran, and China, indicating a rapid spread through Asia
e. Fire: Expanding the Human World
i. Zhoukoudian cave site in China provided important evidence for Homo erectus development dated to 600,000–400,000 yBP.
(1) Evidence for controlled fire usage
(2) Burned stone tools, plants, charcoal, etc.
(3) Fire acted as an agent to ease chewing and initial digestion. Some argue that this increased the energy available to early humans.
f. Homo erectus in Europe (1,200,000–400,000 yBP)
i. Fossils dated to 1,200,000–400,000 yBP
ii. Earliest evidence is from Sierra de Atapuerca site of Sima del Elefant
(1) Partial human mandible and teeth
(2) Animal bones showing cut marks
iii. Other early evidence from Gran Dolina, dated to 800,000 yBP:
(1) Stone tools, animal remains, hominid fossils
(2) Stone-tool cut marks on animal and hominid fossils
g. Evolution of Homo erectus: Biological Change, Adaptation, and Improved Nutrition
i. Increase in body size is one main difference between H. erectus and H. habilis.
ii. The increase took place rapidly, perhaps in as little time as 2.0–1.7 mya.
iii. Climate change and its impact on the food supply may be one reason for the change.
iv. Most significant impact was likely increased access to animal food sources (protein) from hunting.
v. Not limited to genus Homo: dating of stone tools indicates australopithecines may have been able to butcher animals as well.
vi. Tool manufacture and the development of social structures to facilitate group cooperation in hunting were critical.
(1) Acheulian tool complex is represented by a variety of tools and tool materials.
(2) Acheulian tools are more refined than the Oldowan tools.
h. Patterns of Evolution
i. African fossils are the most robust and are similar to Dmanisi forms.
ii. Earlier forms have smaller brains than forms dated later.
(1) Cranial capacity ranges from 650 cc to 1200 cc.
(2) Skull robusticity declined.
iii. Reliance the use of tools changed structure of faces and jaws as a result of food processing.
iv. Changes in social structure and dispersal patterns, and increasing reliance on culture for survival