Rise of Genus Homo

1
Rise of Genus Homo

• Biological Anthropological
• by Stanford, Allen, Anton
• Professor Bender

2
Defining Genus Homo

• Transition from apelike Australopithecus to
  modern human proportions (Homo) occurred in a
  short time period 2.3 1.7 MYA
• By 1.5 MYA long lower limbs and large body size
  existed
• Early Homo not that different from later A.
• In general Homo differs from A. in
• Larger, more rounded brain cases
• Smaller, less projecting face
• Smaller teeth
• Eventually, larger body
• More efficient striding bipedalism
• Shift in foraging strategy?

3
Earliest Genus Homo

• 1960s Louis and Mary Leakey discovered 2 MYA
  partial skeleton of juvenile skull at Olduvai
  Gorge
• Larger brain than A.
• Named Homo habilis skilled human or handy man
  referring to the use and manufacture of stone
  tools
• 1.8 1.9 MYA
• Greatly vary in size, maybe too much for a single
  species

4
Early tool use

• Tool industry particular style of making stone
  tools
• Tools used to remove meat and crack open
  bones
• Butchering sites
• Quarrying sites
• Home base
• Oldowan Industry2.5 MYA
• Simple, unifacial core and flake tools
• Core lumps of stone, often river cobbles
• Flake fragment taken from core
• Hammerstone used to strike flakes from core or
  get marrow from bone

5
Hunting and scavenging

• Earliest hominids almost certainly ate most of
  the same foods that modern apes eat
• Fruit, leaves, seeds, insects, and some animal
  prey
• First evidence of meat eating is use of stone
  tools
• Were early Homo killing the animals or scavenging
  them?
• Passive scavenging
• Confrontational scavenging
• Hunting

6
Who was Homo erectus?

• 1.8 MYA
• Body changes due to environment
• Increased body size
• Changes to postcranial skeleton
• Lengthening of the femur more efficient gait
• Lived in Africa and was the first hominid to
  leave the continent
• 1.7 MYA
• Sometimes called Homo ergaster travelers

7
Homo erectus anatomical features

• Skull
• Thick-boned and robust
• Longer than wide
• Relatively low and angular from the side
• Pentagonal in rear view
• Brain size, larger brains but may just be
  proportional to increased body size
• Jaw robust
• Teeth smaller
• Shovel-shaped incisors

8
Homo erectus anatomical features

• Body size and shape
• Only 3 partial postcranial skeletons found
• Nariokotome boy
• Found in 1984 in Kenya
• Tall individuals as adults (5.5 6)
• Lower limb was long
• Narrow hipped
• These proportions similar to latitudinal gradient
  seen in modern humans for dissipating heat
• Allowing for more activity during the day

9
H. erectus versus H. ergaster

• Main differences are
• H. ergaster
• Region E. Africa (Republic of Georgia)
• Skeleton Thinner cranial bones Less
  pronounced brow ridges
• Date 1.8-1.0 MYA
• H. erectus
• Region Asia
• Skeleton Thicker cranial bones more
  pronounced brow ridges
• Date 1.8-0.05 MYA
• African forms found in association with more
  advanced tools

10
Homo erectus around the world

• H. erectus sites range from 1.8 MYA 100,000
  years ago
• Controversy as to whether H. erectus is found in
  Western Europe
• Fossils found range from 800,000 to 200,000 years
  ago and may be a different lineage
• African origins
• Earliest fossils found all point to Africa

11
Homo erectus around the world

• Dispersal to East Asia
• Oldest H. erectus are from an island in Southeast
  Asia, particularly, Java, dated from 1.6-1.8 MYA
• 1.8 MYA the sea level was much lower and Java was
  not an island but part of the mainland
• Indonesia first specimen found in 1891
• Eugene Dubois thought Asia better origin for
  human line because African apes more robust than
  Asian
• Java Man, just found a skull cap showed large
  brain
• Later found a femur the showed bipedalism
• Found only a few Oldowan-like pieces of technology

12
Homo erectus around the world

• China has youngest but best known
• 800,000 to 200,000 year old
• Peking Man found in 1930s
• Dated from 600,000 to 300,000 years ago
• Lost during WWII when in mid-30s Japan invaded
  China
• Fossils in care of US Marines who guarded the
  train from Beijing to coast to be shipped to San
  Francisco
• Train arrived on 12-7-41 (Pearl Harbor) and
  Marines taken prisoner and fossils never found
• Have measurements and molds
• Peking Man had differences in frontal and
  occipital regions but may have reflected
  intermittent isolation
• Due to glaciations isolation would last 10,000 to
  50,000 years

13
Homo erectus around the world

• Europe
• H. erectus like species existed in Europe as long
  ago as 800,000 years ago
• Fossils of young individuals from age of 3 18
• Mix of characteristics between Neandertals and
  modern humans
• Spain H. actecessor based upon characteristics of
  childs partial crania, which may have
  disappeared as it aged

14
Lifeways of Homo erectus

• H. erectus had two different tool usages
• Showing they possessed advanced cognitive skills
  and had dietary changes
• Stone Age
• Early Stone Age
• 1.8 1.5 MYA Oldowan type tools
• 1.4 MYA 250,000 years ago Acheulean tools
• Biface hand-axes and cleavers
• First time hominids making standardized tools
• Holds sharp edge for longer time, greater length
  of worked edge
• Acheulean tools
• Hand-axes and cleavers
• Holds sharp edge for longer time with greater
  length of worked edge
• Generally convenient size, could be held and used
  without hand fatigue
• Specifically developed for the butchery of large
  animals
• May have been used as digging tools (roots /
  tubers), projectiles (thrown), and as a portable
  core carrier (to make flakes)

15
Lifeways of Homo erectus

• Early Stone Age
• Movius line, In Asia had Oldowan-like tools but
  not true hand axes until much later
• Differences in selective pressures or in raw
  materials?
• Maybe these hominids left Africa before tools
  being used and therefore missed the technology
• Higher quality of diet
• 1.8 MYA humans became much more modern, taller,
  more linear, and with larger brain
• Worldwide geographic expansion
• Shift in better quality (and more quantity) of
  food
• Did we become predators?
• Carnivores small intestine lengthened as large
  intestine shortened meat takes less time to
  process
• Leisure time increased, population density
  decreased, followed migrating herds
• Safe to eat even when unsure of plants

16
Lifeways of Homo erectus

• Human-specific tape worms share a history with
  tapeworms that live in hyenas but diverged from
  them about 1.8 MYA
• Humans shifted from a mainly vegetarian to meat
  diet
• Burnt earth (to indicate cooking fire) 1.6 MYA
• Could have been tuber cooking (baked potato)
• Not much evidence to support this
• Life history
• Evolution proceeds by modifying the developmental
  pattern
• Produces differences we see in adult form
• Large brains
• Humans grow slowly and mature late
• Extremely K-selective
• Two growth spurts, Middle of childhood (around
  5), Adolescent (teen years)
• Teeth show that development of H. erectus was fast

17
H. erectus leaves Africa

• Emigration meant moving across a variety of
  ecosystems, climates, and ecological settings
• Move from tropical and subtropical Africa to more
  seasonally cold Northern Hemisphere of Eurasia
  and Far East
• Requires remarkable adaptability and behavioral
  flexibility to evolve to those conditions in just
  under 2 million years
• African area cooling and drying 2 MYA,
  diminishing forests with large grasslands between
  them
• Increase in quantities of animals and hominids to
  eat them
• Using Oldowan tools to access animal resources
  hominids were not physically adapted to acquire

18
H. erectus leaves Africa

• Higher-quality animal diet resulted in
• Growth of larger bodies and greater ranging
• More linear body shape probably allowed for
  greater midday activity because they coped better
  with the heat
• Entire dispersal seems long
• Change in home range of less than 1 mile a
  year
• Over 10,000 to 15,000 years would be a slow
  dispersal
• Look geologically instantaneous