Homo Flashcards
The Descent of Man (1871)
Darwin predicted that fossils of human ancestors would be found in Africa
The Natural History of Creation in 1866/1868
Haeckel predicted that fossils of human ancestors would be found in Asia
History of Discovery of fossil Homo
Eugene Dubois was a Dutch naturalist and paleontologist influenced by the ideas of Darwin and Haeckel
Who was the first scientist to go looking for fossil evidence of human evolution?
Eugene Dubois
- discovered the Trinil skullcap in 1891 on the banks of the Solo River (Java)
- Dubois first named the discovered fossils Anthropopithecus, then changed to Pithecanthropus erectus
(Got the genus name from Haeckel, who used it to describe a theoretical “missing link”
- These fossils were later grouped with other Asian fossils into the species Homo erectus by Ernst Mayr
The discovery of Australopithecus
- Fossils first discovered at Taungs lime quarry in South Africa
(Australopithecus means “Southern Ape”) - described by Raymond Dart in 1925
- Generic holotype: Taung Child
~ Ape-sized brain
~ Small canines
~ Anteriorly positioned foramen magnum=bipedal
Louis and Mary Leakey
- Began archaeological and paleoanthropological excavations in Eastern Africa (Kenya and Tanzania) in the late 1920s
Olduvai Gorge, Tanzania
Primarily archaeology until Mary finds “Zinj” in 1959
- Louis did not believe Zinj was the tool manufacturer
Original Diagnosis of Homo habilis (Leakey, Tobias, and Napier, 1964)
- reduced post canine teeth
- well-developed speech areas of the brain
- presence of precision grip
- tool use
H. habilis
Generally thought of as the oldest and most primitive species in the genus Homo but taxonomy has been problematic since the beginning
Characteristics of the genus Homo
Homo is a Plio-Pleistocene genus of hominin historically defined by:
- relatively larger brain
- loss of prognathism
- derived limb proportions
- larger stature
- less dimorphism
- smaller molars and premolars
- smaller, more delicately built faces
- parabolic palate (NOT U-shaped)
- Associated with stone tool technology
Oldest fossils assigned to the genus Homo are about 3 Ma
Parabolic dental arcade
- more human-like jaws and teeth
- derived
- teeth are arranged in a shorter, wider arch
Why do species in the genus Homo have more delicately built faces and less prognathic faces?
Reduced subnasal prognathism is related to the change in tooth and jaw structure
Cranial capacity of Homo
Larger cranial capacities than australopiths
- low as 600 cc or as high as 800 cc
The appearance of Homo and the robust australopiths coincide (roughly) with environmental change
- beginning ca. 3 Ma, cooler, drier and with greater variability in climate
- vegetation regime shifts in Turkana Basin at about 2.5 Ma
(more open, grassy habitats)
(less dense forest, trees clumped and patchy; woodland) - rise of the robust australopiths and appearance of Homo around this time
How could robust australopiths and Homo coexist at the same time in the same place?
Niche partitioning
Stone tool types
- Manuports
- Anvils
- Hammerstone
- Core
- Flake
Core
Must be of appropriate material, appropriate size
Flake
- Must have a good striking platform
- Must strike at proper angle
- conchoidal fracture and percussive bulb created when done correctly
The Oldowan Lithic Industry
Until recently, this was the oldest and simplest stone tool technology
- few flakes from unprepared core
- choppers
- mostly unifacial
> 2.5 - 1.76 Ma
Even at old sites, the flaking is well-executed
Oldowan tools were probably used for a variety of applications
- processing plant material
- extracting marrow (scavenging)
- cutting meat (scavenging or maybe hunting)
Cutmarked bones show good evidence for being exploited for food by hominins
Recovered from Hata Mbr of Bouri Fm in 2.5 Ma
- cut marks in meat-rich areas
- percussive marks on marrow-rich shafts
- no stone tools found in concentration or in situ in Hata Mbr
- Paleoenvironment: low energy lake margin
Some flaking may have evolved earlier than the Oldowan
The Lomekwian industry was recently proposed to be earlier than the Oldowan (possibly australopiths)
We do not know very much about body proportions in very earliest Homo
- Most paleoanthropologists think this partial skeleton (OH 62) belongs to Homo habilis
(palate and teeth are Homo) - some features of this specimen resemble australopiths a bit
- Smaller body size
- Relatively long forearms
- Curved fingers
A lot of what we know about early Homo body proportions come from the Homo erectus partial skeleton “Nariokotome Boy”
- larger-bodied (over 100 lbs and over 5 ft)
- human-like proportions of arms and legs (shortened forearms and elongated femora and tibiae)
- shoulder like modern humans
Homo erectus
Oldest hominin species to be found outside Africa
The Acheulean Industry
- beginning 1.76 Ma Acheulean appears
- defined by the presence of handaxes, bifacial flaking, and shaped objects
- more carcasses than at Oldowan sites (more success at scavenging?)
- raw material transport
Hunting or scavenging?
Cutmarks superimposed over tooth marks
Use wear analysis: Primary use is processing vegetal materials plant foods
Hand axes
Highly variable in size and raw material, BUT shape persists for over a million years
Oldowan
2.5 Ma
Acheulean
1.8 Ma
