John Roachfor National Geographic News
April 13, 2006
When the famous skeleton of an early human ancestor known as Lucy was discovered in Africa in the 1970s, scientists asked: Where did she come from?
PER HISTORY
4,600 MILLION YEARS AGO-->EARTH COMES INTO BEING
3,500 MILLION YEARS AGO-->FIRST PRIMITIVE LIFE FORMS
· Due to existence of chemicals that could combine and replicate
· Oxygen levels gradually rose, creating better conditions for diversity of life forms.
· Simple organisms/single celled similar to algae dominated life on earth for almost 3 billion yrs.
570 MILLION YEARS AGO-->COMPLEX ORGANISMS EVOLVE
500 MILLION YEARS AGO-->FIRST VERTEBRATES
430 MILLION YEARS AGO--> FIRST PLANTS
400 MILLION YEARS AGO-->LAND ANIMALS
200-65 MILLION YEARS AGO-->DINOSAURS
65 MILLION YEARS AGO-->DINOSAURS EXTINCT (asteroid?)
25 MILLION YEARS AGO-->PROCONSUL:
(E. Africa-ancestor of apes & forest dweller)
15 MILLION YEARS AGO-->KENYAPITHECUS:
(E. Africa—African apes)
11-7 MILLION YEARS AGO-->SIVAPITHECUS:
(India/Pakistan—orangutan, Asian apes)
ca. 5 MILLION YEARS AGO-->humans branch off from apes
· (Chimps share 97% of our DNA, use tools, communicate in complex ways, & are more closely related to humans than to gorillas)
5-1 MILLION YEARS AGO-->HOMINIDS: prehuman & human
· Australopithecus—prehuman Ethiopia(3-6 mil.)
1) Australopithecus robustus-S. Afr. caves
2) Australopithecus africanus-S. Afr.
3) Australopithecus afarensis—Ethiopia (Lucy) apelike features, herbivore, upright
2.5 MILLION YEARS AGO-->cycle of repeated glaciation begins
2 MILLION YEARS AGO-->HOMO HABILIS
(handyman, toolmaker)
· Ice Ages & interglacial period cycle
· Ice Ages occur every 100,000 yrs.
· Interglacial periods last 20,000 yrs.
· Plants & animals respond to fluctuations by moving N. during milder periods & S. when glaciers advance
· Early hominids follow advance & retreat of animals & plants2.5 MILLION YEARS AGO-->cycle of repeated glaciation begins
2 MILLION YEARS AGO-->HOMO HABILIS
(handyman, toolmaker)
· Ice Ages & interglacial period cycle
· Ice Ages occur every 100,000 yrs.
· Interglacial periods last 20,000 yrs.
· Plants & animals respond to fluctuations by moving N. during milder periods & S. when glaciers advance
· Early hominids follow advance & retreat of animals & plants
1.7-1.5 MILLION YEARS AGO-->HOMO ERECTUS
· (upright, larynx shift enables speech)
· twice brain weight of modern humans
· Scattered groups move N. to Levant (Syria, Lebanon, Israel), then across the then-tropical forests to Arabia & Iran.
· Probably evolved in Africa & began migration due to tectonic plate movement that caused 2000 m. mountain range to jut up, cutting off tree-dwellers from rainforest.
· Savanna requires upright mobility
· Creative and critical thought necessary for survival
1 MILLION-100,000 YEARS AGO-->adaption to cooler climates w/ help of technology
· (evolutionary shift from biology to technology)
· Settle in Eur. (1 million) & Asia from Caucausus to China & Java
· Shelter (Eur. 380,000 yrs. ago)
· Clothing
· Fire (China 460,000 yrs. ago)
· permanent encampments 250,000 yrs. ago
· Efficient tools/weapons—hand ax to kill, cut, etc. 200,000 yrs. Ago
· Art (Bohemia) 200,000 yrs. ago
· H. sapiens, “thinking man” evolves (250,000 yrs. ago) Afr., Eur., Asia
120,000 YEARS AGO-->Neanderthals: Eur. & Levant
· (Germany, Middle East—>Iraq, Siberia, Uzbekistan)
· Massive build (needed lots of fuel/food, which became increasingly scarce.
· Rudimentary speech
100,000-35,000 YEARS AGO-->CroMagnon=>Modern Humans
· (Homo sapiens sapiens)-African origins
· Migrated from Africa to Levant & S. Europe—live side-by-side w/ Neanderthal
· Constantly had to adapt to new surroundings
· Track deer, bring fire rock into cave, predict salmon runs
· Art associated w/ ritual: hunt, birth, death
· Cave paintings and figurines
· Mixed gender groups
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