Cambridge IELTS 11
TEST 144
Questions 20-26
Label the diagram below.
Choose
ONE WORD
from the passage for each answer.
Write your answers in boxes
20-26
on your answer sheet
How a boat is lifted on the Falkirk Wheel
468
FLOW-CHART COMPLETION
TEST 186 READING PASSAGE 3
You should spend about 20 minutes on
Questions 34-39
which are based on
Reading Passage 3 below.
[Note: This is an extract from READING PASSAGE 3 about The History of
the Tortoise]
Walter Joyce and Jacques Gauthier, at Yale University, obtained three
measurements in these particular bones of 71 species of living turtles and tortoises.
They used a kind of triangular graph paper to plot the three measurements against
one another. All the land tortoise species formed a tight cluster of points in the
upper part of the triangle; all the water turtles cluster in the lower part of the
triangular graph. There was no overlap, except when they added some species
that spend time both in water and on land. Sure enough, these amphibious species
show up on the triangular graph approximately half way between the ‘wet cluster’
of sea turtles and the ‘dry cluster’ of land tortoises. The next step was to determine
where the fossils fell. The bones of P. quenstedti and P. talampayensis leave us
in no doubt. Their points on the graph are right in the thick of the dry cluster. Both
these fossils were dry-land tortoises. They come from the era before our turtles
returned to the water.
You might think, therefore, that modem land tortoises have probably stayed on
land ever since those early terrestrial times, as most mammals did after a few of
them went back to the sea. But apparently not. If you draw out the family tree of
all modem turtles and tortoises, nearly all the branches are aquatic. Today’s land
tortoises constitute a single branch, deeply nested among branches consisting
of aquatic turtles. This suggests that modem land tortoises have not stayed on
land continuously since the time of P. quenstedti and P. talampayensis. Rather,
their ancestors were among those who went back to the water, and they then re-
emerged back onto the land in (relatively) more recent times.
Tortoises therefore represent a remarkable double return. In common with all
mammals, reptiles and birds, their remote ancestors were marine fish and before
that various more or less worm-like creatures stretching back, still in the sea, to
the primeval bacteria. Later ancestors lived on land and stayed there for a very
large number of generations. Later ancestors still evolved back into the water and
became sea turtles. And finally they returned yet again to the land as tortoises,
some of which now live in the driest of deserts.
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