Human Evolution Flashcards
Humans vs. Chimpanzees
- protein sequences are 98.5% similar
- 6% of human genes are not found in chimps
- replicate copies of some genes in humans not found in chimps
What are “hominins”?
all species on the human side of the family tree after the split from the branch that became modern chimps
When did hominins diverge from apes?
by 6.0 ma
Earliest Hominin?
Sahelanthropus
- bipedal and small brained
What is the foramen magnum?
the hole at the base of the skull through which the spinal chord passes
What does the position of the foramen magnum at the base of the skull to us?
- directly beneath says erect, vertical posture and bipedalism
- from the rear says horizontal posture
Age of Australopithicines
~4.0 to 1.8 Ma
- bipedal with small brains
- restricted to southern and eastern Australia
- Lucy and Taung Child
Dental Arcades
- rectangular with large canines: ape-like
- semi-parabolic with smaller canines: australopithecines
- parabolic with greatly reduced canines: homo sapiens
Laetoli Ash
- Tanzania
- ~3.6 Ma fossil footprints of bipedal australopithecines
Genus Homo
split from australopithecines approx. 2.5 Ma
- developed crude stone tools
- medium-sized cranial capacity and bipedal
Homo Erectus
~ 1.8 ma
- large brained (at high metabolic cause, increase caloric diet), bipedal
- more carnivorous diet (encouraged cooperation and hunting in groups)
- expanded migration to Africa, Middle East, and South Africa
Homo Neanderthalensis
230 - 30 Kyr
- expanded to Europe, Middle East, and Central Asia
- cold adapted with heavy build and muscular bodies
- some evidence of burial practice
Anatomically Modern Humans
200 thousand years ago
- acceleration of cultural evolution evident through cave paintings (40 Kyr)
Homo Floresiensis
found on Flores Island, Indonesia
- 44,000 - 13,600 years ago
- “hobbits” (3 ft tall)
- cranial capacity is less than chimps but also due to relative size of the bodies
Trends in Human Evolution
- ) Brain size (increase)
- ) body size (increase)
- ) Bipedalism
- ) dental arcade becomes more parabolic with reduced canines
- ) less body hair