280 likes | 478 Views
Apes to Man. Human Evolution. Human evolution is characterized by several types of changes in phenotype: Note: obviously, these aren't the only phenotypic changes characteristic of the human species, but are more noteworthy in regards to human evolution. Changes in brain size & skull shape.
E N D
Human Evolution Human evolution is characterized by several types of changes in phenotype: Note: obviously, these aren't the only phenotypic changes characteristic of the human species, but are more noteworthy in regards to human evolution.
Changes in brain size & skull shape • Smaller to larger brain capacity • Spinal insertion moves from rear to base of skull
Hand Shape • Development of more flexible opposable thumb • Allowed advanced tool use
Pelvis shape • Allowed early hominids to stand & walk upright • Gave advantage of being able to see around them on the savannah
Spine Shape • Changed from "C" shape to "S" shape
Jaw Size • Jaw has reduced in size, reflecting changes in species diet • Size of teeth have generally decreased, especially canines
Timeline of human ancestry ~ 14-16 Million Years to (?) - Ramapithecus & Proconsul • Earliest Ape-like ancestor. • Did not walk upright • Similar in size to the chimpanzee, butstockier
Genus Australopithecus • ~ 3.5 - 1 million years - Genus Australopithecus • Several Species of this genus including • A. afarensis, A.africanus, & A. boeisi • Earliest is Australopithecus afarensis • Very much apelike with an important feature. Was able to walk upright
Homo Habilis • ~ 2 - 1.5 million years - Homo habilis "handy man". • Larger than Australopithecus • Larger brain • Was first to use stone tools.
Homo erectus • ~ 1.5 Million years - ~ 80,000* years . Homo erectus. • Larger than H. habilis • Larger brain • Smaller face • Was the first to use fire • Allowed man to "break out" of Africa into Europe & Asia
Homo neanderthalis ~130,000 - 30,000 years. Homo neanderthalis "Neanderthal man" • Probably not a direct ancestor - but another offshoot from H. erectus • Shorter, stockier, stronger than modern man. Adapted to ice age. • Larger brain size than modern man. • Buried dead with flowers - first evidence of religeous/symbolic thinking.
“Modern” man • ~ 100,000 years to present - Homo sapiens (modern man). • Appears to have originated from H. erectus in Africa, then migrated outwards to Europe & Asia. • Replaced existing species H. erectus & H. neanderthalis
How to make a human: • Millions of years ago, a majority of northern Africa was rainforest. Ancestors to man Rapapithecus and Proconsul, were full arboreal apes living in these forests.
Changes • However, approx. 5 mya the great rift valley formed in east central Africa.
Problems….. • The effect of this rift was to… • Isolate the ape population from their peers in the west. • The rift also created a “rainshadow desert” to its leeward side.
Change of environment. This change in precipitation changed the landscape of the region from rainforest to savannah. The apes needed to develop a new form of transportation since they could no longer brachiate through the trees. Thus, they evolved the ability to walk upright.