Early Homo, particularly erectus, we see a huge gain in size of brains. Why?
Brains make up 2% of body weight, but consume about 20% metabolic energy
This cannot be sustained by nuts and fruit
We needed protein! Explanation?
Brains!
Brains brought us tools, and tools brought us meat. Meat helps balance the metabolic budget.
A very cool adaptation occurred…. Bigger brains=tools=meat=more
energy=but ALSO: meat is easier to digest, and as Homo’s brains got bigger, their intestines got shorter at the same time (unusually small for primates). Now: meat gives brain protein, and we can digest easier as we’ve evolved.
Brain size
1.6-2.3mya First discovery had cranial size of 752cc Smooth rounded head, lacking brow
ridge Human-like parabolic dental arcade
(rather than U shaped like apes and australopithecus)
Found near stone tools (biggest reason along with brain size for “new species”)
H. Habilis
H. Erectus
Tale of thee areas (China, Africa, Indonesia)
Ranges of 850cc-1,200cc (not much smaller than H. Sapiens…us)
Acheulean Tools (hand axes) distinct artifacts
Movius Line
1.65mya-100,000ya (possibly) Characterized by crafting and use:
Bifacial (worked on both sides)
Acheulean Tools
Finds in Indonesia (islands!) Finds in China (Peking Man) Close to Beijing (Peking) a limestone
cave produced many discoveries….
H. Erectus
Peking Man
Fire! China vs Africa. Which one would NEED
fire? Evidence:
*carbon deposits * Ash accumulations (controlled fire sites)?*Burned bone (does this mean
cooking?)?*Fire-cracked stone
Is the above proof that they made/created fire?
Peking Man
Ash Accum.: rain could have washed in Burnt Bones: Hunters or gatherers? Bone could be part of scavenge process Picture a group chasing predator away
with fire torches and “stealing” the catch….
Olduvai Gorge (Tanzania) 1.4mya Turkana Boy! The most
famous/informative erectus find in Africa (67/207 hominoid bones)
In Africa…
Male (based on pelvis, robustness of skull)
2nd molars newly erupted (what does this mean?)
Epiphyseal fusion in some bones: elbow, hip bone (what does that mean?)
Erectus would mature faster than humans due to smaller brain size (estimate Turkana boy to be 10-12 yrs old rather than 13 as a human)
Brain was 880cc, but could have matured to 910cc? He lived 1.6mya.
Turkana Boy
2004 an odd find on an Indonesian island Dubbed “the Hobbit” as Lord of Rings
came out that year….. 1 meter tall, cranial capacity: 380-410
(same as chimp), and lived only 17,000yrs ago; much later than anything other than Homo Sapiens had gone extinct
H. Floreiensis
Very short, no forehead really, and extremely long feet: 10 times longer than most human ratios (foot to femur)
Brain was small, but did exhibit same function of erectus brains (higher brain functions)
Found alone, maybe a mutation, but she was not found alone….
Sophisticated stone tools
H. Floresiensis
Island dwarfism: Looking at 116 island mammals, 38 were smaller, 12 were same size, and 66 were larger than on mainlands
Exs: Carnivores: 13/15, Insects: 4/5 got smaller
Exs: Rodents: 60/69, Marsupials: 3/6 got bigger
Small got big; and big got small Small because of fewer resources?
Bigger bodies are at a disadvantage
Why so small?
Exs: Deer on Vancouver island, elephant ypes are well doc’d (sometimes 50% smaller)
Brains 50 % smaller as well. Remember why? Put it all together….
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