Transcript Human Evolution Chapter 32-Mader

Human Evolution
Chapter 32-Mader
Overview
 Evolution
of Primates
 Evolution of Hominids
 Focus on Homo
 Human Variation
 Humans as a selective agent
Early Primates
Prosimians (~58mya)
 Monkeys (35mya)
 Apes (23mya)
 Hominids (~6mya)

First Arboreal Mammals

The first arboreal mammals probably
resembled shrews:
long snouts.
 Good sense of smell.
 Probably nocturnal.
 Very active.
 CLAWS

First Arboreal Mammals?
Eosimias


The First
Primate?
Comparison with
tree shrew
Prosimians
Lemurs
Tarsiers
Pottos
Loris
Tarsier
Ring
tailed
lemur
Indri
Aye aye
what do
they
sound
like?
This
Slender
loris
Primate Characteristics
 What
is the major selective
pressure associated with life in
the trees?
 How are primates adapted to this
life?
Binocular Color Vision
Primate Hands
Mobile Limbs

Most primates have flat nails as well as
sensitive pads on the undersides of fingers
and toes.


Many also have both an opposable big toe
and thumb.
Mobile limbs and clawless opposable digits
allow primates to freely grasp and release
tree limbs.
Other important features
Upright posture.
 Small litter size.
 Expanded forebrain, larger brain
capacity.

Advantages?
Two main groups of primates:
 1.
Prosimians – lemurs, lorises,
pottos & tarsiers
 2. Anthropoids – monkeys, apes
and man
Prosimians
Lemurs
Tarsiers
Pottos
Loris
ANTHROPOIDS
2. Anthropoids = monkeys + apes + man
a. Monkeys:
• Old world monkeys
• New world monkeys
New World
Monkey:
Flat face
Wide nostrils
Prehensile tail
Old World
Monkey:
Long snout
Close nostrils
Non-prehensile
tail
Taxonomy
 Anthropoids=
Hominoids +
monkeys
 Hominoids= Asian and African
Apes + Hominids
 Hominids= Humans
Proconsul- Ancestor to Hominoids?
Proconsul
A skull of
Proconsul
africanus from
the Kenya
National
Museum.
Selective pressures
East
Africa
Rift
Valley
Skull Comparisons:
Sahelanthropus tchadensis
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6 to 7 million years ago
Flat face like Homo
Cranial capacity about
the same as a chimp
Walked upright
Hominids

Bipedal primates.
To be Human

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standard primate characteristics
upright, bipedal posture
much expanded brain
well defined sexual dimorphism
hidden estrus
altered female sexual response
extended childhood
language
society
culture
Homo erectus, Australopithecus,& Human
Map of Australopithecine Finds
Map of Australopithecus
sites in Africa, with a
focus on the East African
rift valley and limestone
caves of South Africa.
“Lucy” Australopithecus afarensis
An Example of Mosaic Evolution
A. boisei
A. afarensis
A. africanus
A. robustus
Human Ancestors
Human Evolution
Australopithecus africanus


2.8 million years ago
Cranial capacity 460 cc
Genus Homo
Homo habilis
Brain~600cc
“Handy Man”
Artist’s
representation
of a Homo
habilis band
as it might
have existed
two million
years ago.
Olduwan tools
Speech?
Oldowan Tools
Homo erectus

“Upright Man”
 Larger
brain than H. habilis
 Migrated
 Acheulean tools
 More advanced culture?
Homo erectus
Homo erectus
Trends in Skull
Development
Neanderthals

Neanderthal (H. neanderthalensis)
skeletons were first discovered in
Germany’s Neander Valley.

Skeletons date back 200,000 years.
Hominid Brains
Neanderthal Culture
What happened to Neandertals?

Coexisted w/H. sapiens for up to
60,000 years.

Interbred?

Killed off?

Outcompeted?
Neanderthal Man
Homo floresiensis – Nature, Oct. 28, 2004
Nature
Oct 28, 2004
Science, Nov
19, 2004
Homo sapiens

Archaic – 100,000 to
35,000 years BP

Sometimes called Homo
sapiens and Homo sapiens
neanderthalensis

Modern – 35,000 years
BP to present

Anatomically modern

Sometimes called Homo
sapiens sapiens
Cro-Magnons


Oldest fossils to be designated H. sapiens.
Modern humans who entered Asia and
Europe from Africa 100,000 years ago.
 Aurignacian tools.
 Accomplished hunters.
 Language.
Cro-Magnon Man

Cro-Magnon
humans
 1,600 cc cranial
capacity
 Not a different
species, just old
Homo sapiens
from Europe
Artist’s reconstruction of a Cro-Magnon man
Archaic H. sapiens Culture

Art
 Female figurines
 27,000 to 22,000
years ago
 Called “venuses,”
Archaic H. sapiens Culture
Human Variation
Responses to the environment:
• Bergmann’s Rule
•
Allen’s Rule
New World Humans
Sequence of Human Evolution
One of several possibilities
Homo
neanderthalensis
Australopithecus
afarensis
Australopithecus
africanus
Common
ancestor
Homo
habilis
Homo
erectus
Homo
sapiens
Modern
apes