Population movements and genetics: reading answers and analysis
How genetics, teeth and languages have been used to work out when people first reached the Americas. Robert Williams's blood studies pointed to three waves of migration across the Bering Strait, and later DNA, dental and language research mostly backs that three-wave picture, though the dates need caution.
The headings (14-19) cover A to F in order, with G as the example. The map (20-21) and the classification (22-25) both come from D, with E adding two groups. Question 26 is in F.
Answer key and self-check
Type what you wrote and hit mark. Hide the key first if you haven't done the passage yet. Every question number jumps to its explanation.
How to attack this block: C and D are both about blood variants, so split them carefully: C explains how the method measures genetic distance, D gives the results. B poses the old questions about when and how many waves; nothing in it is about causes. F is about teeth.
Question 14
Answer: ivSection A, second and third sentences
Which heading fits Section A?
A number of techniques developed since the 1950s, however, have placed the study of these subjects on a sounder and more objective footing.
Question says → Passage says
Developments in the methodsA number of techniques developed since the 1950s
used to study early population movementsThe best information on early population movements is now being obtained
Why: A contrasts the old evidence (archaeology and fossils) with newer techniques based on genetic material. Its point is how the methods have changed, heading iv.
The trap: vii (long-standing questions about migration) feels like an introduction too, but A doesn't ask any questions. They come in B.
Question 15
Answer: viiSection B, third and fourth sentences
Which heading fits Section B?
But was there one major wave of migration across the Bering Strait into the Americas, or several? And when did this event, or events, take place?
Question says → Passage says
Long-standinghave long been accepted
questions about prehistoric migration to Americawas there one major wave… or several? / when did this event… take place?
Why: B sets out the open questions: how many waves and when. Combined with 'long been accepted', that's heading vii.
The trap: ix (questions about the causes) also promises questions, but B asks how many and when, never why people migrated.
Question 16
Answer: xSection C, last sentence
Which heading fits Section C?
by comparing the Gm allotypes of two different populations (e.g. two Indian tribes), one can establish their genetic 'distance'
Question says → Passage says
How analysis of blood-variantsby comparing the Gm allotypes
measures the closeness of the relationshipestablish their genetic 'distance'
Why: C explains the method: blood protein variants drift over generations, so comparing them shows how closely two groups are related. 'Genetic distance' is closeness, heading x.
The trap: i (results of the blood research) is the classic mistake. C gives no results; it explains how the measurement works. The results are in D.
Question 17
Answer: iSection D, first four sentences
Which heading fits Section D?
From this evidence it was deduced that there had been three major waves of migration across the Bering Strait.
Question says → Passage says
The resultsThey found that / it was deduced that
the research into blood-variantssampled the blood of over 5,000 American Indians
Why: D reports what Williams's team found when they sampled blood: three groups, which led to the three-wave theory. That's the results of the research, i.
The trap: v (migration from Canada) is built from the bracket about the Navajo and Apache moving south. It's one detail, not what D is about.
Question 18
Answer: viSection E, first sentence and last sentence
Which heading fits Section E?
How far does other research support these conclusions?… As would have been predicted by Robert Williams's work, all three groups appear to be descended from the same ancestral (Paleo-Indian) population.
Question says → Passage says
Further genetic evidenceGeneticist Douglas Wallace has studied mitochondrial DNA
relating to the three-wave theoryAs would have been predicted by Robert Williams's work
Why: E brings in a second geneticist, Wallace, whose DNA study matches Williams's prediction. More genetic evidence supporting the three waves: vi.
The trap: i is tempting because Wallace also uses blood samples. But i is about Williams's blood-variant results, which were D; E is a separate, confirming study.
Question 19
Answer: iiSection F
Which heading fits Section F?
The biological anthropologist Christy Turner is an expert in the analysis of changing physical characteristics in human teeth.
Question says → Passage says
Dental evidencethe study of teeth / Tooth analyses
Why: F mentions teeth and languages in its first line, but everything after is about Turner's tooth studies. Heading ii.
The trap: iii (Greenberg's analysis of dental and linguistic evidence) mixes teeth with the next section. Greenberg is a linguist and appears only in G.
Map labelling (routes A-F)
Questions 20-21
How to attack this block: Both answers come from D. Find the wave that matches each date, then follow where that group went: the first wave reached Central and South America, and the Navajo and Apache moved south from Canada much later. Then match that journey to the map.
Question 20
Answer: ESection D, fifth sentence
Which route matches the migration 15,000 or more years ago?
The first, Paleo-Indian, wave more than 15,000 years ago was ancestral to all Central and South American Indians.
Question says → Passage says
15,000 or moremore than 15,000 years ago
migrated along certain routesthree major waves of migration across the Bering Strait
Why: The first wave crossed the Bering Strait from Asia and became the ancestors of all Central and South American Indians. So you want the route that starts in Asia and runs right down into Central and South America, which is Route E in the key.
The trap: Don't pick a route that stops in North America. This wave's descendants are in Central and South America, so the route has to reach that far.
Question 21
Answer: DSection D, sixth sentence (in brackets)
Which route matches the movement 600 to 700 years ago?
ancestors of the Navajo and Apache (who only migrated south from Canada about 600 or 700 years ago)
Question says → Passage says
600 to 700about 600 or 700 years ago
migrated along certain routesmigrated south from Canada
Why: The only thing that happened 600-700 years ago is the Navajo and Apache moving south from Canada. That journey is entirely inside North America, which is Route D in the key.
The trap: It's easy to pick the second wave's Bering Strait crossing (14,000-12,000 years ago) because the same people are mentioned. The recent move is southward from Canada, not from Asia.
Matching features (A-C)
Questions 22-25
How to attack this block: D gives the three waves and who descends from each. The Inuit belong with the Eskimo and Aleut in the last wave, and the Apache with the Na-Dene. E puts the Pima-Papago and Ticuna with the Paleo-Indians, so they share a letter.
Question 22
Answer: CSection D, third sentence and last sentence
In which wave did the ancestors of the Inuit arrive?
The third wave, perhaps 10,000 or 9,000 years ago, saw the migration from North-east Asia of groups ancestral to the modern Eskimo and Aleut.
Question says → Passage says
Inuitthe Inuit (or Eskimo)
the third waveThe third wave
Why: The passage says the Inuit are the Eskimo, and the Eskimo and Aleut came in the third wave. So C.
The trap: If you don't spot that 'Inuit' and 'Eskimo' are the same people, you may guess. The bracket '(or Eskimo)' links them.
Question 23
Answer: BSection D, sixth sentence
In which wave did the ancestors of the Apache arrive?
The second wave, about 14,000-12,000 years ago, brought Na-Dene hunters, ancestors of the Navajo and Apache
Question says → Passage says
Apacheancestors of the Navajo and Apache
the second waveThe second wave
Why: The Na-Dene hunters of the second wave are named as the ancestors of the Apache. B.
The trap: The Apache's move south from Canada 600-700 years ago isn't a separate wave. Their ancestors first reached the continent in the second wave.
Question 24
Answer: ASection E, second and third sentences
In which wave did the ancestors of the Pima-Papago arrive?
Pima-Papago Indians in Arizona… all three groups appear to be descended from the same ancestral (Paleo-Indian) population
Question says → Passage says
Pima-PapagoPima-Papago Indians in Arizona
the first wavePaleo-Indian / The first, Paleo-Indian, wave
Why: Wallace's study traces the Pima-Papago back to the Paleo-Indian population, and D says the Paleo-Indians were the first wave. A.
The trap: Arizona is in North America, which might make you think of the later waves. Ancestry, not location, decides it.
Question 25
Answer: ASection E, second and third sentences
In which wave did the ancestors of the Ticuna arrive?
Ticuna Indians in the Upper Amazon region of Brazil. As would have been predicted by Robert Williams's work, all three groups appear to be descended from the same ancestral (Paleo-Indian) population.
Question says → Passage says
TicunaTicuna Indians in the Upper Amazon region of Brazil
the first wavePaleo-Indian
Why: The Ticuna are the third group in Wallace's study, all descended from Paleo-Indians. They're also South American, which D links to the first wave. A again.
The trap: People avoid repeating A. The question allows it, and both groups in Wallace's study share the same ancestors.
Multiple choice
Question 26
How to attack this block: Read the sentence about Turner's specimens closely: New and Old World, ancient and modern, and they are teeth, not living people. The word 'majority' in one option comes from his conclusion, not from what he examined.
Question 26
Answer: ASection F, third sentence
What did Christy Turner's research examine?
Studies carried out by Turner of many thousands of New and Old World specimens, both ancient and modern
Question says → Passage says
teethspecimens
both prehistoric and modernboth ancient and modern
Americans and AsiansNew and Old World
Why: The specimens are teeth, from the New World (America) and the Old World (including Asia), ancient and modern. That's A.
The trap: C copies 'the majority of prehistoric Americans', but that phrase comes from what Turner concluded, not what he examined. B turns specimens into living people.
C borrows 'majority of prehistoric Americans' from Turner's findings. What he examined was teeth from New and Old World, ancient and modern.
Words from this passage worth keeping
objective footing(A)
a basis that relies on facts, not opinion
colonisers(B)
people who settle in a new land
calibrated(C)
adjusted against a scale so it can measure accurately
deduced(D)
worked out from evidence
ancestral(D)
belonging to earlier generations of a group
minimally(F)
only to a very small degree
gives credence to(G)
makes an idea more believable
with caution(G)
carefully, without full trust
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The full Cambridge 7 Test 3 reading paper: all three passages, 60 minutes, marked the second you finish with a review of every answer. Already done it? Take it again and see if the same traps still get you.
Cambridge IELTS 7, Test 3, Reading Passage 2. The passage and questions belong to Cambridge University Press and are not reproduced here. We quote short extracts only as evidence for our own commentary, and the answers are published for self-marking. Get the book for the full text, or sit the test on Langujet.
