Hominid Debate Lesson
Student Notes
Syllabus Dot Points covered in this lesson
9.8.3 Debate continues on the relationship between hominid species

9.8.3.2.3 – Outline and examine the evidence for the pattern of human
migration based on
o
o

the ‘Out of Africa’ model
the theory of regional continuity (multi-regional hypothesis)
9.8.3.3.3 - Gather and process information from secondary sources to
analyse and evaluate the evidence for two different models of human
evolution
Lesson Outline
Students will gather, analyse and evaluate a variety of appropriate secondary sources
of information concerning both the ‘out of Africa’ and regional continuity (multi-regional
hypothesis) theories.
After processing the information students will develop an audio podcast in which they
debate the validity of both theories against themselves.
Possible Secondary Information Sources
Websites
Becoming Human
http://www.becominghuman.org/documentary
A great website which delivers a series of documentaries related to the study of
hominids. Provides a summary of both theories and also audio of key proponents of
each theory (Yoel Rak, Milford Molpoff).
Direct students to click on ‘Begin the Program’ after loading. Then direct students to
click on ‘lineages’ at the top of the page before scrolling over ‘related exhibits number
8 (modern humans populate the globe)’ at the bottom of the page.
National Geographic
https://www3.nationalgeographic.com/genographic/atlas.html
Interactive timeline detailing the proposed migration of both theories.
Geocities -Paleoanthropology
http://www.geocities.com/palaeoanthropology/Multiregional.html
Summary of Scientific American journal paper explaining both theories.
Stephen Jay Gould Site – Todd Billings Paper
http://www.stephenjaygould.org/ctrl/billings_africa.html
Paper discussing the basis of both theories.
Printed Material
The use of any current approved biology text book would prove useful.
e.g. Brotherton, J. and Mudie, K. [Eds] (2004). Heinemann Biology (2nd edition),
Heinemann, Port Melbourne, Vic.
Migration Debate Summary Notes (CSU)
See summary notes below (to be printed and given to each student) from HSC online
provided by Charles Sturt University:
http://hsc.csu.edu.au/biology/options/human_story/2939/Bio983_18Mar04.html#f
our
Human Migration Debate – Summary Notes
Background
Humans are very good at colonising different environments. The genus Homo originated in
Africa and the first wave of humans to leave Africa were Homo erectus. After this point there
is a difference of opinion as to what happened next. The two models that are used to describe
the next stage of human migration are the ‘Out of Africa’ model and the regional continuity
theory

Anthropologists agree that human origins came from Africa. The oldest hominid fossils
are found there. Homo erectus spread throughout the world travelling through Europe
and into Asia.

The ‘Out of Africa’ model proposes a more recent African origin of modern humans
who replaced the existing Neanderthals and other archaic species of hominins. This was
the second time that hominins had migrated from Africa and this time they were the
modern species Homo sapiens.

The ‘Out of Africa’ theory is a replacement theory where one species was replaced by
the modern humans coming out of Africa. This means that any racial differences must
have occurred at a later time. The evidence for this theory comes from the fossil and
genetic evidence.

The fossil evidence is stronger for the ‘Out of Africa’ model than for the regional
continuity theory. The oldest fossil of Homo sapiens has been found in Africa. In
Africa there are transitional fossils between pre- modern (archaic) and modern types.
This suggests that humans evolved in Africa.

The genetic evidence for the ‘Out of Africa’ model first came from the University of
California in Berkeley in the 1980’s. By mapping the mitochondrial DNA (mtDNA)
and then comparing the results from different groups of humans throughout the world it
is possible to work out the relationships between the groups. The small number of
genes in the mitochondria makes it easier to map than the entire nuclear genome. Over
time mutations occur causing changes to the sequence of the DNA. The more similar
the mtDNA the closer the relationship between the groups. If the mutations that occur
are regular, then a ‘molecular clock’ can been used to work out when groups last shared
a common ancestor. Mitochondria have a maternal pattern of inheritance. This is
because at fertilisation the egg cell (ovum) provides the mitochondria. If a mother has
no female offspring then that line of descent would disappear. Over time and by
chance, the lineage can be traced back to one woman. This has been tracked back to a
hypothetical woman who lived in Africa and is known as ’Mitochondrial Eve.’

More genetic evidence comes from tracing the genetic diversity of populations. The
populations in Africa have the greatest genetic diversity. This requires a longer time to
occur and supports the ‘Out of Africa’ model.

The regional continuity theory states that there was local evolution in different regions
from Homo erectus to Homo sapiens. This occurred simultaneously many times all over
the world and in each region. Interbreeding occurred between the regions to maintain
an interbreeding species but not enough to eliminate regional differences. Each regional
group of Homo erectus developed into that region's Homo sapiens. Modern Chinese
developed from the group of Homo erectus living in China.

Evidence for this comes from the Zhoukoudian caves near Beijing and from locations
in Java and in Australia. In northern Asia features of modern human skulls including
face shape, cheekbones and shovel-shaped incisors can be traced back to the Peking
man specimens from China. The fossils from Java can be arranged in a sequence with
no evidence of African migration. Early Australian fossil hominids show that there
were several migrations of humans into Australia. These occurred when the sea level
was lower than today forming land bridges. Some of the Australian fossils show
similarities to the fossils from China (Lake Mungo fossils) and others are more similar
to the fossils from Indonesia (Kow swamp fossils). This is still controversial.

Comparison of the evidence for each model: For ‘Out of Africa’ to be correct then
anatomically modern humans should appear in Africa earlier than elsewhere,
transitional fossils from archaic humans to modern humans should only occur in Africa,
and there should be no regional continuity of features from ancient to modern humans
outside of Africa. For the regional continuity theory to be supported then modern
humans will appear throughout the world at the same time, transitional fossils should be
found everywhere. Continuity of anatomy from ancient to modern forms should be
clear.
Regional Continuity
Out of Africa
Key Points to Cover When Presenting Debates



Outline the theory of the hypothesis in question.
State evidence supporting theory
Refute evidence used to support alternate theory if possible