KEY CONCEPT Humans appeared late in Earth’s history.
I. Humans share a common ancestor with other primates. A. Primate Characteristics 1. Moveable fingers and toes 2. Flat nails 3. Prehensile (grasping) hands Color vision Front facing eyes Enlarged brains
B. Primates evolved into prosimians and anthropoids. Prosimians are the oldest living primates They are mostly small and nocturnal Examples: lemurs, lorises, tarsiers
Prosimian = Lemurs
Prosimian = Lorises
Prosimian = Tarsiers
2. Anthropoids are humanlike primates.
a. Characteristics of Anthropoids Well developed collar bone Rotating shoulder Dental formula (molars, premolars, canine, incisors) Opposable thumbs
Many have prehensile tails C. Anthropoids are subdivided into the New World monkeys, Old World monkeys and hominoids New World Monkeys: Marmosets, Howlers, Spider Monkeys, Squirrel Monkeys All live in trees Many have prehensile tails
New World = Marmosets
New World = Howlers
New World = Spider
New World = Squirrel Monkey
2. Old World Monkeys: Macaque, Colobus, Baboon Most travel and forage (at least part of the time) on the ground Have larger brains that New World Monkeys
Old World = Macaque
Old World = Colobus
Old World = Baboons
3. Hominoids – Orangutans, Bonobos, Chimps Hominoids are divided into hominids, great apes and lesser apes 1. Hominids include living and extinct humans a. Walk upright b. Have long lower limbs c. Opposable thumbs d. Relatively large brains 2. Great apes include gorillas, chimps and orangutans 3. Lesser apes include gibbons
Great Apes = gorillas
Hominoids/Great Apes = Orangutans
Hominoids = Bonobos
Hominoids/Great Apes = Chimps
Hominoid/Lesser Apes = Gibbons
E. Walking Upright (a characteristic of humans) 1. Bipedal means walking on two legs which allows… Foraging carrying infants and food using tools Requires: a. Cup shaped pelvis b. S shaped spine c. Toes aligned d. Larger brain
II. There are many fossils of extinct humans 1. Most hominids are classified either as Australopithecus or Homo 2. Australopithecines were a successful genus a. Australopithecinus afarensis i. Lived 3 – 3.9 million years ago ii. Cranial Capacity is 1/3 of modern humans iii. Humanlike limbs Australopithecus afarensis Homo habilis Homo neanderthalensis Homo sapiens
3. The Homo genus first evolved 2.4 million years ago a. Homo habilis i. Lived 2.5 – 1.6 mya ii. “Handy man” – used tools iii. Ate meat iv. Speech Australopithecus afarensis Homo habilis Homo neanderthalensis Homo sapiens
b. Homo Neanderthalensis i. “Neanderthals” ii. Larger cranial capacity than humans iii. Thick brow ridges and protruding teeth iv. Tools v. Wore Clothing Buried their dead Replaced by modern humans Australopithecus afarensis Homo habilis Homo neanderthalensis Homo sapiens
III. Modern humans arose about 200,000 years ago 1 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 culture b. There is a trend toward increased brain size in hominids c. Characteristics: i. High forehead ii. No brow ridge Australopithecus afarensis Homo habilis Homo neanderthalensis Homo sapiens