Section 16.1Human Evolution

Objectives• Recognize the

adaptations of primates

• Compare and contrast the diversity of living primates

• Distinguish the evolutionary relationships of primates

Human Evolution

• Primates: adapted for an arboreal (tree-dwelling) existence.

• Primates range in size from the 30-gram (1 oz) Pygmy Mouse Lemur to the 200-kilogram (440 lb) Mountain Gorilla.

Primate Classification

• I. Prosimians- Lemurs and tarsiers.

• Cat-like face, large eyes• Oldest primate:

Purgatoriosus (squirrel sized).

• II. Old world Monkeys (tails)– Ex. Baboons,

Mandrill

• From Africa and Asia

• Larger than other primates.

• III. New World Monkeys (flat-nosed)– Ex. Howler monkey,

pygmy marmoset (world’s smallest monkey)

• Smaller than other primates

• Exist in Central and South America

• IV. Great Apes• Larger-bodied,

no tail• Primarily ground

dwelling

A) Orangutans• orang hutan, meaning

"forest person".

• (orange-man)• Borneo (Asia)-

found only Asia

B) Gorilla• Largest living

primate• Central Africa• Mountain gorilla• Lowland gorilla• The DNA of gorillas is

98%–99% identical to that of a human

C) Chimpanzees and Bonobos

• West and central Africa, Congo river

• species are the closest living relatives to humans

• The Common Chimpanzee has an omnivorous diet, a troop hunting culture based on beta males led by an alpha male, and highly complex social relationships.

D) Humans• DNA evidence

indicates that modern humans originated in east Africa about 200,000 years ago

• Humans have a highly developed brain, capable of abstract reasoning, language, introspection and problem solving.

Human Ancestors• I.

Australopithecus afrensis: southern ape-man, a far region of Ethiopia

• Had a small brain size

Lucy (Australopithecus) • Fossil discovered by

Don Johansen• Oldest- known

upright waling hominid- (means human)

• Shorter than modern humans

• Lived between 3 and 5 million years ago

Characteristics of Lucy• 1 meter tall• About 60 lbs

Brain size of Lucy• 450 cc or cm 3

(cubic centimeters)• (1cc=1ml or 450

grams or ½ pound

Proof of Bipedalism• Bipedal: Walked

upright on two legs

• Evidence:– Locking knee cap– Straightened

spine– Broader hip– Forarmen

magnum is the bottom of the skull (skull hole)

Advantages of upright walking

1. Stand taller2. Move more

efficiently, long distances

3. Freed up hands for: • Food gathering• Defense-weapon and

tool use

Lucy Facial Features:1. No forehead2. Heavy brow ridge3. Wide flat nose4. Projecting (prognathic) jaws5. Human-like teeth, no canines

II. A africanus • 3.6 -2.4 MYA (million years ago)• Bipedal• 60-90 lbs• Human-like teeth• Sexual dimorphism-difference in

size and structure between the genders

• Fossil- “Taung Baby’– Raymond Dart- 1924

• Africanus- gracile• Robust-A. robustus• A. boisei side

branch (not our ancestor)

• Large jaws and molars for eating nuts and roots

(side note)Gracile: skinny, thin,

small, gracefulRobust: husky, fat

III. Homo habilis • “handy man”• First stone tool users• Louis Leakey:1964

– 750 cc/750 mL- brain size

• Lived 1.8- 2 MYA• Smaller molars• Scavengers not hunters

– Tools used to scrape meat or break bones for marrow

IV. Homo erectus • “Upright man”• 1.6 million – 250,000 years ago• Evolved to be very “Human Like”• Skeleton: longer and stouter• Height: 6 ft• Tool Users: hand axe• Lived in family groups• Hunted larger game• First fossil: 1891 “Java Man”

• Migrated out of Africa

• Fossils have been found in Spain, Russia, Indonesia, and Middle East

• First to use fire

• Out of Africa: Homo sapiens evolved in Africa and migrated out. The different races represent slight regional differences

Multi Regional Theory • Homo

erectus migrated out an evolved independently in the different races of homo sapiens.

V. H. neandertalenis Neanderthal man formerly a

subspecies of H. sapiens• 150,000-30,000 years ago• Short, stocky• 5 ft tall• Large, broad nose• Well adapted for cold• Aggressive hunter• Not a direct ancestor of H. sapiens

• First to bury their dead

• Stones marked their graves

Neanderthal Extinction Coincides with the appearance of

modern humans in Europe1. Killed by humans2. Interbred with humans3. Infected by human diseases4. Out-competed by modern humans/

out-smarted by early humans

VI. Homo sapiens • “Wise Humans”• Archaic H. Sapiens:• (Ancient)

Appeared 150,000 years ago

• He did not seem to have culture, or creativity

• Did evolve in Central Africa

VI. Homo sapiens (continued)

• Modern Humans:• Appeared 50,000

years ago• Highly advanced tool

making • Hunter gatherers • Agriculture and

civilizations

Alternatives• Anti Evolution: beliefs which try to

debunk science.• Pseudo Science: not based on

scientific method.• Anomalous: doesn’t fit the

accepted theory• Anachronism: Something out of

place in time

creationism

• A literal belief in the biblical account of Creation as it appears in the Book of Genesis. Creationists believe that the creation of the world and all its creatures took place in six calendar days; they therefore deny the theory of evolution.

intelligent design  

• The assertion or belief that physical and biological systems observed in the universe result from purposeful design by an intelligent being rather than from chance or undirected natural processes.