key concept humans appeared late in earth’s history

12.6 Primate Evolution

KEY CONCEPT Humans appeared late in Earth’s history.

12.6 Primate Evolution

I. Humans share a common ancestor with other primates.A. Primate Characteristics

1. Moveable fingers and toes2. Flat nails3. Prehensile (grasping) hands4. Color vision5. Front facing eyes6. Enlarged brains

12.6 Primate Evolution

B. Primates evolved into prosimians and anthropoids.

1. Prosimians are the oldest living primatesa. They are mostly small and nocturnalb. Examples: lemurs, lorises, tarsiers

12.6 Primate EvolutionProsimian = Lemurs

12.6 Primate Evolution

Prosimian = Lorises

12.6 Primate Evolution

Prosimian = Tarsiers

12.6 Primate Evolution

2. Anthropoids are humanlike primates.

12.6 Primate Evolution

a. Characteristics of Anthropoids

– Well developed collar bone

– Rotating shoulder– Dental formula

(molars, premolars, canine, incisors)

– Opposable thumbs

12.6 Primate Evolution

1. New World Monkeys: Marmosets, Howlers, Spider Monkeys, Squirrel Monkeysa. All live in treesb. Many have prehensile tails

C. Anthropoids are subdivided into the New World monkeys, Old World monkeys and hominoids

12.6 Primate Evolution

New World = Marmosets

12.6 Primate Evolution

New World = Howlers

12.6 Primate Evolution

New World = Spider

12.6 Primate Evolution

New World = Squirrel Monkey

12.6 Primate Evolution

2. Old World Monkeys: Macaque, Colobus, Baboon

a. Most travel and forage (at least part of the time) on the ground

b. Have larger brains that New World Monkeys

12.6 Primate Evolution

Old World = Macaque

12.6 Primate Evolution

Old World = Colobus

12.6 Primate Evolution

Old World = Baboons

12.6 Primate Evolution

3. Hominoids – Orangutans, Bonobos, Chimps

D. Hominoids are divided into hominids, great apes and lesser apes1. Hominids include living and extinct humans

a. Walk uprightb. Have long lower limbsc. Opposable thumbsd. Relatively large brains

2. Great apes include gorillas, chimps and orangutans3. Lesser apes include gibbons

12.6 Primate Evolution

Great Apes = gorillas

12.6 Primate Evolution

Hominoids/Great Apes = Orangutans

12.6 Primate Evolution

Hominoids = Bonobos

12.6 Primate Evolution

Hominoids/Great Apes = Chimps

12.6 Primate Evolution

Hominoid/Lesser Apes = Gibbons

12.6 Primate Evolution

E. Walking Upright (a characteristic of humans)

1. Bipedal means walking on two legs which allows…a. Foragingb. carrying infants and foodc. using tools

2. Requires:a. Cup shaped pelvis

b. S shaped spinec. Toes alignedd. Larger brain

12.6 Primate Evolution

12.6 Primate Evolution

1. Most hominids are classified either as Australopithecus or Homo2. Australopithecines were a successful genus

a. Australopithecinus afarensisi. Lived 3 – 3.9 million years agoii. Cranial Capacity is 1/3 of modern humansiii. Humanlike limbs

II. There are many fossils of extinct humans

Australopithecusafarensis

Homo habilis Homo neanderthalensis

Homo sapiens

12.6 Primate Evolution

12.6 Primate Evolution

3. The Homo genus first evolved 2.4 million years agoa. Homo habilis

i. Lived 2.5 – 1.6 myaii. “Handy man” – used toolsiii. Ate meativ. Speech

Australopithecusafarensis

Homo habilis Homo neanderthalensis

Homo sapiens

12.6 Primate Evolution

12.6 Primate Evolution

Australopithecusafarensis

Homo habilis Homo neanderthalensis

Homo sapiens

b. Homo Neanderthalensisi. “Neanderthals”ii. Larger cranial capacity than humansiii. Thick brow ridges and protruding teethiv. Toolsv. Wore Clothingvi. Buried their deadvii. Replaced by modern humans

12.6 Primate Evolution

12.6 Primate Evolution

III. Modern humans arose about 200,000 years ago 1. Homo sapiens fossils date to 200,000 years ago

a. Human evolution is influenced by a tool-based cultureb. There is a trend toward increased brain size in hominidsc. Characteristics:

i. High foreheadii. No brow ridge

Australopithecusafarensis

Homo habilis Homo neanderthalensis

Homo sapiens

12.6 Primate Evolution