Chapter 8
THE ORIGINS AND EVOLUTION OF EARLY
HOMO
INTRODUCTION
What separates hominins from hominids? (the
humans from the apes)
 One thing is tool use
 Chimpanzees and other primates use tools, but
not to the extent that humans do

INTRODUCTION

For the rest of the fossils we study (the genus
Homo) we will use the biocultural approach
 We
will look at anatomy and features
 And we will look at behavior and culture
INTRODUCTION
Traditionally there was debate over whether
Asia or Africa is the origin of humans
 When a fossil ancestor skull was found in Asia
in the 1800s, people thought that Asia was our
birthplace
 Now we know Africa is, and that our ancestors
migrated out of Africa and around the world

EARLIEST ANCESTORS
Today we will focus on two of the earliest
human ancestors:
 Homo habilis
 Homo erectus

SPLITTERS VS LUMPERS
Some scientists see each anatomical
difference as valid and make many species
 Some see lots of variation and group fossils
together
 I am more of a lumper but do split a few things
Ex. Paranthropus is its own group

FAMILY TREE
We have discussed early primates, the
Australopithecines, Paranthropus, and now we
move the genus Homo
 All species in this genus are humanlike; they
make tools and are intelligent, but still do not
have large brains

HOMO HABILIS
HOMO HABILIS
Modern humans rely on technology to survive,
but our ancestors had to rely on their bodies
and brains
 Fossil skulls were found near Paranthropus but
had bigger brains and more human-like trends

 Rounder
skull
 Smaller teeth
 Nonhoning canine
TRENDS
We will focus on continuing trends in this
genus, but both biological and cultural
 Biology:

 Teeth
get smaller
 Face gets flatter
 Skull gets rounder
HOMO HABILIS
HOMO HABILIS
Means “Handy Man”
 First hominin known to use stone tools
 2 mya
 Small body, short legs, bidpedal, similar to
Australopithecines but slightly larger brains
 Important: they also had hands that could
manipulate tools

HOMO HABILIS: INTELLIGENCE AND TOOL USE
Hand: precision grip
 Brain: slightly larger size (650 cc)
 Use of reason, strategy, planning
 Small teeth and weak chewing power show that
tools were important for habilis’ survival

 As
tools become more important, teeth and
chewing muscles get weaker
HOMO HABILIS
It is not just about brain size, but also about
brain shape
 Post-orbital constriction shows growth of frontal
lobe

HOMO HABILIS
It is not just about brain size, but also about
brain shape
 Post-orbital constriction shows growth of frontal
lobe

HABITAT
Warm season with grasses and diverse
habitats
 Increased food resources  increased
exploitation of resources
 Tools would help them exploit land
 Digging roots and tubers
 Processing food
 Possible scavenging

TOOL TECHNIQUE

Olduwan tools:
 Part
of the Lower Paleolithic Technique
 Crude, simple
 But show manipulation of materials for specific
purpose
HOMO ERECTUS
A new species appeared 1.8 mya
 Finally get a larger brain
 Large brow ridges


Both H. habilis and H. erectus originated in
Africa, but some H. erectus migrated to Asia
SPLIT?
Some split H. erectus and H. ergaster
 Fossils found in Africa are ergaster
 Fossils found in Asia are erectus


I will refer to them all as H. erectus
HOMO ERECTUS
Important anatomical features:
 Sagittal keel: bump on top of skull because
brain is asymmetrical
 Wide part of skull is at the base: “mushroomshaped head”

HOMO ERECTUS
TRENDS
Homo habilis






Teeth small
Small brain
Small browridge
Small body
Long arms
Short legs
Homo erectus






Teeth smaller
Larger brain
Larger browridge
Tall body
Shorter arms
Longer legs
HOMO ERECTUS IN AFRICA
Earliest record is about 1.8 mya
 Nariokotome Boy/Turkana Boy: full skeleton
that shows modern anatomy (*in video*)

 Longer
legs means this was a true biped (no more
utilizing trees)
 Adolescent male who would have been more than 6
feet tall
 900 cc brain
NARIOKOTOME BOY
HOMO ERECTUS IN ASIA
Began to migrate soon after evolving in Africa
 First fossil is Dmanisi skull, found in the
Republic of Georgia
 Zhoukoudian in China

HOMO ERECTUS IN ASIA
Widespread migration through Asia
 Survived for more than 1 million years, so very
successful
 One skull found has marks on bone: either
cannibalism or body modification

FIRE
H. erectus is the first hominin thought to have
used fire
 Benefits:

 Keep
warm
 Stay safe (scar away predators)
 Cook food (fewer parasites and easier to chew)
 Cooking food also releases more nutrients
 Extend daylight (more time for cultural behaviors)
ADAPTATIONS
From H. habilis to H. erectus, males’ heights
increased 33% and females’ 37% in 200,000
years
 Much of this probably because of increase in
animal protein

ADAPTATIONS

However, there is debate over whether erectus
was a scavenger or a hunter
 Keep
this in mind when watching video and doing
extra credit
The video discusses exhaustion hunting
 The tools they made were not hunting weapons
 So they were scavengers (at least at first), and
then became hunters

TOOL TECHNIQUE

Acheulian tools
 Still
Lower Paleolithic
 More complex than habilis’
 Handaxe: sharp edge for cutting and scraping (good
for scavengers)
 More refined: showed higher level of skill