3/18/14 Chapter 10: What is a hominid? • What us different about humans? ! Speech ! Cognition ! Culture ! Upright walking ! Non-honing chewing • HominiD- the term used in 1993 for bipeds. Us, and our ancestors, as distinguished from apes (older, outdated) currently, it includes apes. • HominiN- contemporary term for bipeds. (N for NEW) • Most of the field accepts that out closest relatives are chimpanzees because of overwhelming evidence and some fossil records. • How did our common ancestor behave? o Lived in Africa o Use hand-me downs o Live in small-scale societies • Our common ancestor was probably characterized by: o Open “fission-fusion communities”- a big group exists, but breaks up into small groups, then back together (closed to outsiders) o Some solitary foraging- can be dangerous because of predators o Promiscuous mating- is still in chimpanzees, in humans it is all over the map. Different cultures have different marriage and mating ideals. Here in tally we shoot for monogamy, but it is not the reality. “Serial monogamy” is closer to reality o Female migration- beneficial because of genetic variation, 2011 dental data support this o Males may have been more bonded to each other than females- the core of the group is made up of related males since they don’t migrate out like females. o Stalk and attack patrolling by males • Our common ancestor probably looked like: o 3’-4’ tall, sexually dimorphic o Apelike body proportions (long arms) o Hair somewhat reduced- thermoregulatory; bare skin with a lot of sweat glands to cool off skin o Dark skin- very HOT environment, this is adaptive o Big front teeth- fossil record evidence o Feet, knees, and pelvises starting to change " bipedalism- not fully striding, but there are signs of the pelvis, spinal chord, and back in process of adapting for bipedalism o Small brain- ape sized (300-350 cc) o Walked like ducks (waddled) o Knuckle-walked at times (controversial: Falk says yes, Larson says no. Very little evidence) o Slept in trees • Why did our ancestors get up and walk habitually on 2 legs?! o One of the biggest controversies in paleo-politics o Freeing hands, running after game (Mary Leaky believes in persistence hunting,) hunting (looking over tall grass,) efficient for staying cool (Stanley Wheeler said that standing tall exposes a small region of your body to direct sunlight,) tool production, sexual signaling. 3/20/14 • Non-Honing Chewing o Honing versus apical wear o Shearing (them) versus grinding (us) o Male-male aggression • Why did hominids evolve? o Owen Lovejoy’s theory… men want to help women because they want to have sex and impregnate them again o More food supports more infants, which can lower IBI o Males develop bipedalism" gather food for children o Females feed children" can have more healthy offspring quicker o Suite of anatomies and behaviors co-evolve # Food provisioning # Pair bonding (Reduced canine size) # Cooperation # Bipedalism • Important pre-ostalopithoscenes (lucy is an ostalopithoscene) o Sahalanthropis- Tchadensis- the oldest candidate in the known fossil record for a hominin was found in Tchad, Central Africa. Skull. Discovered by Michelle Brunet. The virtual endocast happens to show detail in the frontal lobes: 2 sulci that have a configuration that you see in 4 endocasts of austrolophithecus. o Orrorin (Millennium Ancestor)- 6 mya in East Africa o Lucy- Found in the Afar region in East Africa, species Afarensis, 3.4 mya 3/25/14• Who were the first hominids? o Ardipithecus ramidus (nicknamed Ardi) # Middle awash valley, Ethiopia, Africa (forest) # 4.4 million years old # Female, 110 lb # Claim bipedal ground, clambered in trees # International team lead by T White and Y. Haile-Selassie # Highly UNLIKELY to have been bipedal o Paranthropus- IS NOT PART OF AUSTRALOPITHECUS, only australopithecine—“robust”—“side branch” in relation to modern humans # Appear to have been an evolutionary dead end # Morphology suggests they are not ancestral # 2 TYPES: • 1. Aethiopicus o Ethiopia and Kenya, Africa o 2.5 myo o woodlands and grasslands o sagittal crest and large molars • 2. Boisei o Ethiopia, Tanzania, and Kenya, Africa o 1.2-2.3 myo o grasslands o sagittal crest o theyre called robust because of their thick skulls o but body size was pretty normal compared to other Australopithecus • 3. Sediba o south Africa, malapa cave o youngest date for australopethicus o nh1: juvenile male, 11-13 y/o o nh2: female o upward turned shoulders o ancestoral to homo o short pelvis, long arms, thinner mandible o The “non-robust” autstralopithecines were the first hominids! o First habitat # Forested (chads mosaic) # Hot times on the savanna • Australopithecus anamenis o Kenya and Ethiopia, Africa (woodland) o 4 million years old o M. Leakey and T. Whitte o Anatomies: bipedal (based on the shin bone) and nonhoning canine o Australopithecus afarensis: includes LUCY # 3.2 million years old # little baby endocast found in similar area # cranial morphology may not have been as advanced # big male also found—these discoveries underscore the fact that this was a highly sexually dimorphic species # M. Leakey uncovered trail of footsteps in Laetoli, Tanzania; 3.6 mya (footprints had round heel, toes, double arch.) # Significant because it showed although brain size was not advanced, bipedalism had already developed. The feet came first. o Kenyanthropus # Kenya, Africa # 3.5 myo o Garhi # Ethiopia, Africa # 2.5 myo # large teeth, long legs, stone tools • The First Tool Makers o Oldowan stone tools (2.6 myo) o Australopithecus first stone tool makers: not Homo o Oldest cut marks on bone 3.4 myo o Tools looked like rocks, sometimes called “pebble tools” • South African Australopithecines o Australopithecus africanus # 2-3 mya# small non honing canines; large premolars and molars # bipedal o paranthropus robustus # 1.5-2 mya # small, non-honing canines; very large premolars and molars # bipedal o Australopithecus sediba # 1.9 myo (malapa cave) # forest and grassland # anatomy: small brain, small teeth, human like hands and pelvis, mosaic foot Chapter 11: The Origins and Evolution of Early Homo • 1891: Eugene Dubois (1858-1940) o Dutch physician and anatomist, medical scientist, o Homo