Human Evolution

Did we evolve from apes?

Humans DID NOT evolve from apes we have a common

ancestor

Scopes “Monkey Trial” 1925

John Scopes a Dayton Tennessee Biology teacher taught about the theory of evolution to his students despite it being against the law.

Scopes was arrest, tried, and found guilty. Two years later Scope’s guilty sentence was

overturned.The topic of evolution did not appear back in

school books until the 1960s.

Apes

Apes include:1) Gibbons2) Orangutans3) Gorillas4) Chimpanzees

Chimpanzee Characteristics that are similar to humans

- Make and use simple tools pg 402- Can learn ex: can be taught sign language- Self aware beings ex: chimps in front of a

mirror

Human Branch of Primate Tree

- Occurred about 5 to 7 million years ago

- This branch is called Hominids

5 Major Traits of Hominids

1) Increased brain size2) Shorter jaws3) Bipedal posture (upright posture to walk)4) Reduced size difference between the sexes

(human males average about 1.2 times the weight of females)

5) Family structure (long term bonding between mates, newborns dependent upon mothers, long period of parental care)

Two Main Groups of Hominids

1) Australopithecus 2) Homo

Australopithecus afarensisFact• Scientists argue if this species really is

the closest relative to the Homo branch on the phylogenetic tree

• Australopithecines overlapped in time with species of Homo

Australopithecus afarensisCharacteristics1) Bipedal2) Arms are long in proportion to body size (suggests arboreal locomotion might of

occurred)3) Skulls are ape like4) Long jaws5) Small brain volume

Famous Australopithecus afarensis

Lucy• Skelton of a young female found in Ethiopia in

1974Characteristicsa) 3 feet tallb) Arms long but her hands and feet like modern

day humansc) Large head d) Jaw and forehead stuck out from her face

Why is Lucy Famous?

She is the oldest (3 million years old), most complete erect walking human ancestral skeleton found to date

Laetoli Footprints

Facts:• Hominid footprints found in Tanzania in

1976 that dated back 3.6 million years• Oldest evidence of bipedal walking• Scientists believe these footprints were

made by an Australopithecus afarensis

Homo habilius

FIRST species of the homo genus to appear

Characteristics1) Reduction in protruding face (jaw

underneath the brain)2) Smaller molars3) Associated with Oldowan tool industry

Homo sapiens are the sole remaining member of the hominid

family treeThis is us!