Download S292 Explaining the emergence of humans

S292 Explaining the emergence of humans
End of Course Assessment S292 03I
Cut-off date Friday 31 October 2003
THIS ECA CAN ONLY BE SUBMITTED BY STUDENTS WHO STARTED THE COURSE IN
MAY 2003 OR SEPTEMBER 2003.
Before attempting this assessment, read the general instructions and advice on End of Course
Assessments that is available as a separate file in the top level of the S292 computer conference.
A brief history of views on ‘man’s place in nature’ is provided in Unit 1 of Lewin’s book Human
Evolution. The notion of a ‘gap’ between humans and animals was discussed in a religious context
long before Darwin published his book The origin of species, in 1859. In the 19th century, the
dominant religious view was that humans are ‘special’ and set apart from, and above, animals. You
will have read how, even after Darwin, views on the natural order of animals and humans, the
‘Great Chain of Being’, remained unchanged. Before Darwin, the mechanism for the origin of the
Great Chain of Being was divine creation; after Darwin, the mechanism switched to natural
selection.
Charles Darwin was convinced of the close evolutionary relationship between apes and humans. He
had visited London Zoo in 1837 to see an orangutan, Jenny, the very first ape to be brought to
England. Jenny disturbed those people who saw her, because her close resemblance to humans
blurred their perception of a sharp distinction between people and animals. Darwin suggested that
humans had evolved from apes in Africa, because the predators and harsh climate there provided
the pressure for natural selection to promote evolution of a biped from an ape. In 1863, Darwin’s
friend Thomas Huxley, in his book Evidence as to Man’s place in Nature, agreed that humans and
great apes share an evolutionary relationship. Yet even Huxley was convinced of ‘the vastness of
the gulf between man and the brutes’.
The modern synthesis of evolution links Mendelian genetics and palaeontology to Darwin’s theory
of evolution by natural selection. Molecular biology provides important contributions to our
understanding of evolution, and supports the close evolutionary relationship between humans and
African apes. Natural selection as a process is applicable to humans, as it is to all species, and the
gulf between humans and other species is not especially great. Nevertheless, the big question for
palaeoanthropologists today remains the same as it was in the 19th century:
What makes a human?
For this ECA, you will be investigating this question scientifically, rather than from a philosophical
point of view. Classification of humans in the Superfamily Hominoidea reflects the close
evolutionary relationship between modern humans and apes. Detailed groupings within the
Hominoidea reflect differences between modern humans and African apes (Lewin, Table 15.1).
However, modern humans Homo sapiens are the sole survivors of a number of Homo species that
existed between about 2 million years and 27 000 years ago. For the purposes of this ECA the term
‘humans’ will be used specifically for modern Homo sapiens but you should be aware that some
palaeoanthropologists use the term ‘humans’ for all species of Homo.
Palaeoanthropologists have traditionally recognized four key events during the evolution of
humans: terrestriality; bipedalism; encephalization; culture. There is general agreement that these
events did occur and that they encompass the features that make us human. There has been
considerable argument about the timing and significance of each of these events in the evolution of
humans (Lewin, Unit 2). There has also been controversy about whether one of them, culture, is
unique to humans and extinct hominoid species on the evolutionary line to Homo sapiens.
The following questions ask you to explore the four key events and to use evidence from living
species, fossils, and artefacts to demonstrate ‘what makes a human’.
In Lewin’s book there is relevant information on this ‘big question’ in Units 1, 2, 3, 10, 15, 16, 17
19, 20, 21, 23, 30, 31; you may find information in other units too. In addition, you will need to use
the web links and news items on the S292 website to get additional information and illustrations;
relevant links are highlighted in the course calendar and also in the reference list at the end of this
ECA. You are advised to use this guidance as it can take a long time to search for relevant material
Copyright  The Open University 2003
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on the web. There will be additional help on the FirstClass conference, in particular the practice
ECA, and the ‘skulls of the week’.
Practice ECA
The practice ECA can be found in the top level of the S292 FirstClass conference. It is compiled
from a previous ECA in which the ‘big question’ was ‘Who were our ancestors?’ and comprises a
set of questions based on a provided evolutionary tree for Homo sapiens. It is worthwhile working
through the questions and reading the sample answers. Doing the questions provides an opportunity
for developing and practising the skills of selecting specific lines of evidence, and using them to
support your views. Although the subject area of the practice ECA is not exactly the same as for
this ECA, the skills required for answering the questions are the same.
Skull of the week
Help with selecting the factual content of your answers for this ECA is provided in the top level of
the FirstClass conference as the ‘Skull of the week’; some of these demonstrate how to select and
use information from websites.
You should answer Part I and select three questions from the five in Part II.
PART I
This part consists of one compulsory question that carries 25 marks. Your answer should be no
more than 400 words.
Question 1
(a) Outline, in no more than two or three sentences for each, the four key events that are supposed
to have transformed our primate ancestors into humans.
(5 marks)
(b) For each of the events in (a):
(i) state what kinds of evidence you would look for from available fossil and artefactual specimens
and living species, to establish that the event took place in human evolution and to find out when it
occurred; and
(ii) explain briefly how you would use this evidence for your purpose, e.g. for measurements or
comparisons.
(20 marks)
Note that detailed descriptions of specific named fossils and artefacts are not required; just mention
the types of evidence, e.g. fossils of skulls, or observations on named living species.
PART II
This part contains five questions from which you should answer any three. Each question carries
20 marks and, unless stated otherwise, your answer to each question should be no more than 350
words.
Question 2
Robert Martin (Anthropological Institute, Zurich) defines primates as ‘arboreal inhabitants of
tropical and subtropical ecosystems’ (Lewin, Unit 10). Humans, of course, are not arboreal but
are terrestrial, i.e. they live on the ground. African hominoids living during the Miocene, e.g.
Proconsul dated at around 22 million years, are considered to be the ancestors of apes. The
illustration on the top of page 91 of Lewin shows that these apes are considered to have been
partly arboreal and partly terrestrial, rather like chimpanzees except that they were not knuckle
walkers. The hominine clade is thought to have originated around 6 million years ago. Fossil
evidence suggests that the ancestral species for Homo include one of the australopithecines,
hominines living in Africa from around 4.5–1.2 million years ago. Many palaeoanthropologists
give Australopithecus afarensis a prominent place in evolutionary trees for Homo (see forest of
evolutionary trees in Lewin, page 128). The following questions ask you to explore the origin and
significance of terrestriality in Homo, and to draw a conclusion about whether terrestriality was a
key event in the evolution of humans.
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(a) List four features of the chimpanzee skeleton that are linked to arboreality. For each feature,
describe in one or two sentences the equivalent feature in Australopithecus afarensis and Homo
sapiens.
(8 marks)
(b) Name two of the earliest known species of Homo. For each, select a named fossil that has
sufficient of the post-cranial skeleton available to provide evidence about whether this species was
partly arboreal, or totally terrestrial. Summarize features in each of your chosen fossils that provide
evidence for arboreality (if any) and/or terrestriality.
(8 marks)
(c) Drawing on your answers to (a) and (b), explain whether (i) terrestriality can be regarded as a
key event in human evolution and unique for humans, and (ii) the event was a sudden transition.
(4 marks)
Question 3
Bipedal walking using a striding gait is a unique feature of modern humans. No other primate
walks in this way, although some species of ape can walk bipedally for short distances. Lewin
points out that anthropologists have looked for uniquely human explanations for human bipedalism.
The following questions explore the biological origins of human bipedalism.
Write no more than 250 words in total for your answers to (b) and (c).
(a) In a table of your own design, list at least five features of the skeleton of modern Homo sapiens
that can be linked to bipedal walking. Add to your table columns for the chimpanzee and for
Australopithecus afarensis in which you compare the same skeletal features for these two species.
Give your table a title.
(11 marks)
(b) What specific anatomical fossil evidence is available for the earliest appearance of bipedalism
in a hominine? Select a fossil(s) of a named early hominine and write a brief description of features
that support bipedalism. Summarize any evidence for arboreality in your selected fossil species.
Note that for news of fossil finds of early hominines reported after 1999, you will need to look at
the S292 website.
(6 marks)
(c) Does the evidence you present in (a) and (b) support the view either that bipedalism was the
primary hominine adaptation, or that bipedalism is a special attribute of Homo?
(3 marks)
Question 4
Lewin points out that the relative size of the human brain is three times larger than that of apes. The
following questions ask you to explore encephalization in human evolution.
Write no more than 250 words in total for your answers to (b) and (c).
(a) Devise a table, listing eight selected hominid species, which shows the indicators of changes in
brain size and structure during hominid evolution. For each fossil species you include, mention one
or two specimen finds, where they were found and when the species existed (mya or kya). For
instance: Homo imaginius; Piltdown (or identify by number, CCL-889), Sussex, England;
4.6–3 mya. Alongside each species tabulate any information you can find about brain size,
encephalization quotient (EQ), and brain structure, e.g. lobes of the brain or areas linked to
language. You should aim to compare the chimpanzee, two selected australopithecine species and
five Homo species, including H. neanderthalensis and fossil modern H. sapiens.
(10 marks)
(b) Outline the evolutionary trends for brain size and structure in hominines, drawing on
information from your table in (a) to support your answer, including numerical values for brain size
and EQ.
(7 marks)
(c) Drawing on your answers to (a) and (b), explain whether (i) we can conclude from the data
available that encephalization is one of the key events in human evolution, and (ii) increased brain
size is one of the features that ‘makes a human’.
(3 marks)
Question 5
From the 1940’s to the early 1970’s culture was regarded as the defining feature for hominines.
The use of tool technology was one aspect of culture that prior to 1960 was regarded as being
definitive for Homo; you may be aware of the term ‘Man the Tool Maker’. Hence culture, in terms
of tool technology, was regarded as one of the key events that transformed primates into humans.
This question asks you to look for evidence of tool use in hominids other than Homo, and then use
that evidence to test the application of definitions of culture.
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(a) Is there evidence that extinct hominine species other than Homo used stone or bone tools?
Describe one named example of a find to support your answer.
(5 marks)
(b) Describe one example of use of stone tools in a wild population of an extant species of ape.
(5 marks)
(c) The biological definition of culture is that it is behaviour transmitted repeatedly through social
or observational learning to become a population level feature. To what extent can the use of stone
tools in extant ape species be regarded as culture? To answer this question you need to outline
evidence that a particular way of using of stone or bone tools is a characteristic of a named
population of chimpanzees (or another ape species) and is transmitted by behaviour in that
population.
(5 marks)
(d) Does the evidence in your answers to (a)–(c) support the view that culture defined in biological
terms was one of the key events that transformed our primate ancestors into humans? Refer to
points made in your answers to (a)–(c) in your conclusion.
(5 marks)
Question 6
Culture can be defined in exclusively human terms, as technological, mythological, aesthetic and
institutional activities (Glossary, Lewin, 1999). Can we accept that this definition applies to
modern humans only?
Art, painting, drawing and sculpture, involve representing the real world in a different form, and
requires a high level of cognitive skills. Do the fossil and artefactual evidence support the view that
art is a defining feature for modern humans? Can we say that the ability to create art is one of the
features that makes a human?
In answering parts (a)–(c), you will be considering these questions.
(a) Describe one line of artefactual evidence for artistic ability in Neanderthals. Name the location
and date of the find, if the information is available, and suggest a date for the emergence of artistic
expression in Europe.
(5 marks)
(b) Describe four named examples of finds of art attributed to modern Homo sapiens. In order to
address the big question, you need to select the earliest finds that you can track down from Lewin
and/or the S292 website. Select one example of cave art and one example of portable art from each
of Africa and Europe to provide the evidence that you need.
(10 marks)
(c) Using the evidence that you described in (a) and (b), discuss whether (i) you can conclude that
art is a unique and defining feature for modern humans, and (ii) the ability to create art is one of the
features that ‘makes a human’.
(5 marks)
References
List all of the references cited in your answers to the four questions. You may prefer to list the
references at the end of each answer, or provide a list of all the references used at the end of the
ECA. Mention references in your text, where appropriate.
(5 marks)
Summary of marks available
Part I (Question 1)
25 marks
Part II (three of Questions 2–6 for 20 marks each)
60 marks
For reference list
5 marks
For use of at least three correctly referenced additional sources of evidence
5 marks
For presentation of your answers, including for keeping answers within the word limit, organization
of answers into paragraphs, and correct spelling of scientific terms.
5 marks
References accessible from S292 website
Guidance on the use of the S292 website for finding information relevant for this ECA will be
provided on the S292 FirstClass conference. Useful web links, most of which are accessible from
the S292 website, are listed below:
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S292 website: Site Reviews
Smithsonian National Museum of Natural History
OH62 – ‘More questions than answers’
http://www.mnh.si.edu/anthro/humanorigins/ha/oh62.html
The Laeotoli footprints
http://www.mnh.si.edu/anthro/humanorigins/ha/laetoli.htm
Primate Research Institute, Kyoto (Kyoto University website) – Bossou chimpanzees.
Blombos Cave, South Africa (hosted by Stony Brook University, New York)
Orrorin tugenensis and Ardipithecus ramidus
Once using this site, the hominid index, other species available too, e.g. Australopithecus
afarensis
The cave of Chauvet, Pont d’Arc.
Once using this site, it is worth clicking on:
Time and space: archaeological context – (Aurignacian artefacts)
http://www.culture.fr/culture/arcnat/chauvet/en/espa2.htm
The cave of Lascaux
Kostenki
S292 website: News Online
‘Oldest ape-man fossils unearthed (Millenium Man)’ 4 December 2000 (Orrorin)
‘Old man (Millenium Man)’ 5 December 2000 (Orrorin)
‘Ape-man ate termites’ 16 January 2001 (A. robustus)
‘Fossil find may be missing link’ 23 April 1999 (A. garhi)
‘New species found’ 23 April 1999 (A. garhi)
‘Hominid fills gap in fossil record’ 22 April 1999 (A. garhi)
Other relevant websites
Chimpanzee cultures
http://chimp.st-and.ac.uk/cultures/deWaal.htm
Apollo 11 cave, Namibia, including images of ancient rock art in Africa
http://www.natmus.cul.na/exhib/rockart/apollo11.html
Tetsuro Matsuzawa: Essays on evolutionary neighbours
Essay 4. Stone tools and computers
http://www.pri.kyoto-u.ac.jp/koudou-shinkei/shikou/chimphome/essay/0_essay.htm
Notes
You can choose to illustrate your answers with diagrams, where you judge appropriate.
You may produce your ECA using a word-processing package and any other software that you
wish, or you may write it by hand.
The presentation of the ECA will be assessed, as well as the content, so you should make sure that
your writing is clear and concise, that only relevant material is included and that it follows the
structure suggested.
When you have completed this assessment, follow the instructions for submission given in the
general instructions and advice.
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