‘When evolution runs backwards’- Reading Answer Explanation – CAM – 10
Here are explanations of the Questions of passage named, ‘When evolution runs backwards’ which is from the Cambridge 10 book. The Questions that have been asked are ‘MCQs’ and Yes/No/Not Given. You will find the locations of the Reading Answers, Keywords(highlighted and underlined) and justifications.
READING PASSAGE 3: When evolution runs backward
| Question | Answer |
| 27 | C |
| 28 | D |
| 29 | C |
| 30 | B |
| 31 | A |
| 32 | F |
| 33 | G |
| 34 | A |
| 35 | B |
| 36 | D |
| 37 | NOT GIVEN |
| 38 | YES |
| 39 | NO |
| 40 | YES |
Questions 27-31
Choose the correct letter, A, B, C or D.
Write the correct letter in boxes 27-31 on your answer sheet.
27. When discussing the theory developed by Louis Dollo, the writer says that
A. it was immediately referred to as Dollo’s law.
B. it supported the possibility of evolutionary throwbacks.
C. it was modified by biologists in the early twentieth century.
D. it was based on many years of research.
Location: 3rd paragraph
Explanation: The main keyword ‘Louis Dollo’ helps to locate an answer in the third line of the paragraph. ‘Early 20th-century biologists came to a similar conclusion, though they qualified it in terms of probability, stating that there is no reason why evolution cannot run backwards …’ This question can be answered by eliminating the options. The writer states that they qualified it in terms of probability means it was modified by biologists. Thus, the best option is C.
Answer: C
‘When evolution runs backwards’- Reading Answer Explanation – CAM – 10
28. The humpback whale caught off Vancouver Island is mentioned because of
A. the exceptional size of its body.
B. the way it exemplifies Dollo’s law.
C. the amount of local controversy it caused.
D. the reason given for its unusual features.
Location: 4th paragraph
Explanation: The main keywords ‘humpback’ and ‘Vancouver’ helps to locate an answer in the last two lines of the paragraph. ‘a humpback whale with a pair of leglike appendages over a metre long, complete with a full set of limb bones, was caught off Vancouver Island in Canada. Explorer Roy Chapman Andrews argued at the time that the whale must be a throwback to a land-living ancestor. ‘I can see no other explanation…’Here, the writer states that humpback whale with a pair of leglike appendages refers to unusual feature. Thus, the best answer is D.
Answer: D
‘When evolution runs backwards’- Reading Answer Explanation – CAM – 10
29. What is said about ‘silent genes’?
A. Their numbers vary according to species.
B. Raff disagreed with the use of the term.
C. They could lead to the re-emergence of certain characteristics.
D. They can have an unlimited life span.
Location: 5th paragraph
Explanation: The main keyword is ‘silent genes’ and its reference is there in the last lines of the paragraph. ‘They reasoned that…others may be the result of genes being switched off. If these silent genes are somehow switched back on, they argued, long lost traits could reappear…’Here, ‘lost traits could reappear’ and ‘re-emergence of certain characteristics’ means the same. ‘re-emergence’= reappear, Characterstics= traits. Thus, the answer is C.
Answer: C
30. The writer mentions the mole salamander because
A. it exemplifies what happens in the development of most amphibians.
B. it suggests that Raffs theory is correct.
C. it has lost and regained more than one ability.
D. its ancestors have become the subject of extensive research.
Location: 6th paragraph
‘When evolution runs backwards’- Reading Answer Explanation – CAM – 10
Explanation: The main keyword ‘mole salamander’ is there in the last line of the paragraph. ‘In other words, metamorphosis in mole salamanders is an atavism. The salamander example fits with Raff’s 10million-year time frame…’ Here, this line means that salamander is used to exemplify the Raff’s theory. This example matches with Raff’s theory and prove that it was correct. Thus, the answer is B.
Answer: B
31. Which of the following does Wagner claim?
A. Members of the Bachia lizard family have lost and regained certain features several times.
B. Evidence shows that the evolution of the Bachia lizard is due to the environment.
C. His research into South American lizards supports Raffs assertions.
D. His findings will apply to other species of South American lizards.
Location: 8th paragraph
Explanation: The main keyword ‘Wagner’ helps to locate an answer in the last line of the paragraph. ‘According to his analysis of the Bachia family tree, the toed species re-evolved toes from toeless ancestors and, what is more, digit loss and gain has occurred on more than one occasion over tens of millions of years…’ Here, the writer states that Bachia family have gained and lost many features. Moreover, ‘more than one time’ means ‘several times’. Thus, the answer is A.
Answer: A
Questions 32-36
Complete each sentence with the correct ending, A-G, below.
Write the correct letter, A-G, in boxes 32-36 on your answer sheet.
32. For a long time biologists rejected
Location: 1st paragraph
Explanation: The answer to this question is in the second line of the paragraph. ‘For the better part of a century, most biologists have been reluctant to use those words, mindful of a principle of evolution that says ‘evolution cannot run backwards…’ Here, ‘biologists have been reluctant’ and ‘biologists rejected’ means the same. Moreover, ‘evolution cannot run backwards’ means it cannot be reversible. Hence, the answer is F.
Answer: F
33. Opposing views on evolutionary throwbacks are represented by
Location: 3rd paragraph
Explanation: The location of the answer is in the beginning of the paragraph. ‘While Lombroso was measuring criminals, a Belgian palaeontologist called Louis Dollo was studying fossil records and coming to the opposite conclusion…’ Here, this line states that they were studying in different fields as Dollo was finding fossil records whereas Lombroso was measuring criminals. They come to opposing conclusions. Thus, the answer is clear.
Answer: G
‘When evolution runs backwards’- Reading Answer Explanation – CAM – 10
34. Examples of evolutionary throwbacks have led to
Location: 5th paragraph
Explanation: The location of the answer is in the first two lines of the paragraph. ‘Since then, so many other examples have been discovered that it no longer makes sense to say that evolution is as good as irreversible. And this poses a puzzle: how can characteristics that disappeared millions of years ago suddenly reappear?…’ This statement states that examples led to a puzzle which means question that how characters which were disappeared millions of years ago reappeared. Here, ‘millions years ago’ clarifies that these were long lost traits. Thus, the answer is A.
Answer: A
‘When evolution runs backwards’- Reading Answer Explanation – CAM – 10
35. The shark and killer whale are mentioned to exemplify
Location: 9th paragraph
Explanation: The main keywords ‘shark and killer whale’ helps to find an answer in the first line of the paragraph. ‘One possibility is that these traits are lost and then simply reappear, in much the same way that similar structures can independently arise in unrelated species, such as the dorsal fins of sharks and killer whales…’ Here, ‘independently arise’ means ‘occurrence’. Moreover, ‘unrelated’ and ‘different’ means the same.
Answer: B
36. One explanation for the findings of Wagner’s research is
Location: 9th paragraph (Third line)
Explanation: The writer says, ‘Another more intriguing possibility is that the genetic information needed to make toes somehow survived for tens or perhaps hundreds of millions of years in the lizards and was reactivated…’Here, this means genetic information survived for millions of years. That means there was continued existence of genetic information.
Answer: D
‘When evolution runs backwards’- Reading Answer Explanation – CAM – 10
A. the question of how certain long-lost traits could reappear.
B.the occurrence of a particular feature in different species.
C. parallels drawn between behaviour and appearance.
D. the continued existence of certain genetic information.
E. the doubts felt about evolutionary throwbacks.
F. the possibility of evolution being reversible.
G. Dollo’s findings and the convictions held by Lombroso.
Questions 37-40
Do the following statements agree with the claims of the writer in the Reading Passage?
In boxes 37 – 40 on your answer sheet, write –
YES if the statement agrees with the claims of the writer
NO if the statement contradicts the claims of the writer
NOT GIVEN if it is impossible to say what the writer thinks about this
37. Wagner was the first person to do research on South American lizards.
Location: 8th paragraph
Explanation: Though the writer states about the South American lizards in the paragraph. But there is no information regarding Wagner was the first person to do research. Thus, no information available.
Answer: Not Given
‘When evolution runs backwards’- Reading Answer Explanation – CAM – 10
38. Wagner believes that Bachia lizards with toes had toeless ancestors.
Location: 8th paragraph
Explanation: The location of the answer is in the last lines of the paragraph. ‘According to his analysis of the Bachia family tree, the toed species re-evolved toes from toeless ancestors and, what is more, digit loss and gain has occurred on more than one occasion over tens of millions of years…’Here, the question statement is same as the passage statement.
Answer: Yes
39. The temporary occurrence of long-lost traits in embryos is rare.
Location: Last paragraph
Explanation: The main keyword is ‘embryos’ and its reference is there in the second line of the paragraph. ‘Early embryos of many species develop ancestral features…’Here, ‘long-lost traits’ refers to ‘ancestral features’. In addition to this, the writer says that many species develop these features so it was not rare. The question statement contradicts the passage statement. Thus, the answer is clear.
Answer: No
‘When evolution runs backwards’- Reading Answer Explanation – CAM – 10
40. Evolutionary throwbacks might be caused by developmental problems in the womb.
Location: Last paragraph
Explanation: The location of the answer is in the fourth line of the paragraph. ‘But if silent genes degrade within 6 to million years, how can long-lost traits be reactivated over longer timescales? The answer may lie in the womb. Early embryos of many species develop ancestral features…’
Here, this line states that developmental problems answer lie in womb.
Answer: Yes
‘When evolution runs backwards’- Reading Answer Explanation – CAM – 10
‘Second nature’- Reading Answer Explanation – CAM – 10