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The fossil remains of the first flying vertebrates, the [#permalink]
10 Oct 2007, 16:48
The fossil remains of the first flying vertebrates, the pterosaurs, have intrigued paleontologists for more than two centuries. How such large creatures, which weighed in some cases as much as a piloted hang-glider and had wingspans from 8 to 12 meters, solved the problems of powered flight, and exactly what these creatures were—reptiles or birds—are among the questions scientists have puzzled over.
Perhaps the least controversial assertion about the pterosaurs is that they were reptiles. Their skulls, pelvises, and hind feet are reptilian. The anatomy of their wings suggests that they did not evolve into the class of birds. In pterosaurs a greatly elongated fourth finger of each forelimb supported a wing-like membrane. The other fingers were short and reptilian, with sharp claws. In birds the second finger is the principal strut of the wing, which consists primarily of feathers. If the pterosaurs walked on all fours, the three short fingers may have been employed for grasping. When a pterosaur walked or remained stationary, the fourth finger, and with it the wing, could only turn upward in an extended inverted V-shape along each side of the animal’s body.
The pterosaurs resembled both birds and bats in their overall structure and proportions. This is not surprising because the design of any flying vertebrate is subject to aerodynamic constraints. Both the pterosaurs and the birds have hollow bones, a feature that represents a savings in weight. In the birds, however, these bones are reinforced more massively by internal struts.
Although scales typically cover reptiles, the pterosaurs probably had hairy coats. T. H. Huxley reasoned that flying vertebrates must have been warm-blooded because flying implies a high rate of metabolism, which in turn implies a high internal temperature. Huxley speculated that a coat of hair would insulate against loss of body heat and might streamline the body to reduce drag in flight. The recent discovery of a pterosaur specimen covered in long, dense, and relatively thick hairlike fossil material was the first clear evidence that his reasoning was correct.
Efforts to explain how the pterosaurs became airborne have led to suggestions that they launched themselves by jumping from cliffs, by dropping from trees, or even by rising into light winds from the crests of waves. Each hypothesis has its difficulties. The first wrongly assumes that the pterosaurs’ hind feet resembled a bat’s and could serve as hooks by which the animal could hang in preparation for flight. The second hypothesis seems unlikely because large pterosaurs could not have landed in trees without damaging their wings. The third calls for high waves to channel updrafts. The wind that made such waves however, might have been too strong for the pterosaurs to control their flight once airborne.
1. It can be inferred from the passage that scientists now generally agree that the
(A) enormous wingspan of the pterosaurs enabled them to fly great distances
(B) structure of the skeleton of the pterosaurs suggests a close evolutionary relationship to bats
(C) fossil remains of the pterosaurs reveal how they solved the problem of powered flight
(D) pterosaurs were reptiles
(E) pterosaurs walked on all fours
7. It can be inferred from the passage that some scientists believe that pterosaurs
(A) lived near large bodies of water
(B) had sharp teeth for tearing food
(C) were attacked and eaten by larger reptiles
(D) had longer tails than many birds
(E) consumed twice their weight daily to maintain their body temperature
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Re: RC Inference - please explain the reason [#permalink]
10 Oct 2007, 18:56
lnaik wrote: The fossil remains of the first flying vertebrates, the pterosaurs, have intrigued paleontologists for more than two centuries. How such large creatures, which weighed in some cases as much as a piloted hang-glider and had wingspans from 8 to 12 meters, solved the problems of powered flight, and exactly what these creatures were—reptiles or birds—are among the questions scientists have puzzled over.
Perhaps the least controversial assertion about the pterosaurs is that they were reptiles. Their skulls, pelvises, and hind feet are reptilian. The anatomy of their wings suggests that they did not evolve into the class of birds. In pterosaurs a greatly elongated fourth finger of each forelimb supported a wing-like membrane. The other fingers were short and reptilian, with sharp claws. In birds the second finger is the principal strut of the wing, which consists primarily of feathers. If the pterosaurs walked on all fours, the three short fingers may have been employed for grasping. When a pterosaur walked or remained stationary, the fourth finger, and with it the wing, could only turn upward in an extended inverted V-shape along each side of the animal’s body.
The pterosaurs resembled both birds and bats in their overall structure and proportions. This is not surprising because the design of any flying vertebrate is subject to aerodynamic constraints. Both the pterosaurs and the birds have hollow bones, a feature that represents a savings in weight. In the birds, however, these bones are reinforced more massively by internal struts.
Although scales typically cover reptiles, the pterosaurs probably had hairy coats. T. H. Huxley reasoned that flying vertebrates must have been warm-blooded because flying implies a high rate of metabolism, which in turn implies a high internal temperature. Huxley speculated that a coat of hair would insulate against loss of body heat and might streamline the body to reduce drag in flight. The recent discovery of a pterosaur specimen covered in long, dense, and relatively thick hairlike fossil material was the first clear evidence that his reasoning was correct.
Efforts to explain how the pterosaurs became airborne have led to suggestions that they launched themselves by jumping from cliffs, by dropping from trees, or even by rising into light winds from the crests of waves. Each hypothesis has its difficulties. The first wrongly assumes that the pterosaurs’ hind feet resembled a bat’s and could serve as hooks by which the animal could hang in preparation for flight. The second hypothesis seems unlikely because large pterosaurs could not have landed in trees without damaging their wings. The third calls for high waves to channel updrafts. The wind that made such waves however, might have been too strong for the pterosaurs to control their flight once airborne.
1. It can be inferred from the passage that scientists now generally agree that the (A) enormous wingspan of the pterosaurs enabled them to fly great distances (B) structure of the skeleton of the pterosaurs suggests a close evolutionary relationship to bats (C) fossil remains of the pterosaurs reveal how they solved the problem of powered flight (D) pterosaurs were reptiles (E) pterosaurs walked on all fours
7. It can be inferred from the passage that some scientists believe that pterosaurs (A) lived near large bodies of water (B) had sharp teeth for tearing food (C) were attacked and eaten by larger reptiles (D) had longer tails than many birds (E) consumed twice their weight daily to maintain their body temperature
Can you please post all the questions...?
Thank you..
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Re: RC Inference - please explain the reason [#permalink]
10 Oct 2007, 19:14
bkk145 wrote: Can you please post all the questions...? Thank you..
I agree with bkk, I don't like reading entire passages to do one question.
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Or two, as the case may be.
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Is this a GMAT passage.? It seems much longer then anything I have seen although I have only seen 3 or 4 passages. Just curious. Its length is very similar to LSAT passages.
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CEO
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Re: RC Inference - please explain the reason [#permalink]
10 Oct 2007, 23:37
lnaik wrote: The fossil remains of the first flying vertebrates, the pterosaurs, have intrigued paleontologists for more than two centuries. How such large creatures, which weighed in some cases as much as a piloted hang-glider and had wingspans from 8 to 12 meters, solved the problems of powered flight, and exactly what these creatures were—reptiles or birds—are among the questions scientists have puzzled over.
Perhaps the least controversial assertion about the pterosaurs is that they were reptiles. Their skulls, pelvises, and hind feet are reptilian. The anatomy of their wings suggests that they did not evolve into the class of birds. In pterosaurs a greatly elongated fourth finger of each forelimb supported a wing-like membrane. The other fingers were short and reptilian, with sharp claws. In birds the second finger is the principal strut of the wing, which consists primarily of feathers. If the pterosaurs walked on all fours, the three short fingers may have been employed for grasping. When a pterosaur walked or remained stationary, the fourth finger, and with it the wing, could only turn upward in an extended inverted V-shape along each side of the animal’s body.
The pterosaurs resembled both birds and bats in their overall structure and proportions. This is not surprising because the design of any flying vertebrate is subject to aerodynamic constraints. Both the pterosaurs and the birds have hollow bones, a feature that represents a savings in weight. In the birds, however, these bones are reinforced more massively by internal struts.
Although scales typically cover reptiles, the pterosaurs probably had hairy coats. T. H. Huxley reasoned that flying vertebrates must have been warm-blooded because flying implies a high rate of metabolism, which in turn implies a high internal temperature. Huxley speculated that a coat of hair would insulate against loss of body heat and might streamline the body to reduce drag in flight. The recent discovery of a pterosaur specimen covered in long, dense, and relatively thick hairlike fossil material was the first clear evidence that his reasoning was correct.
Efforts to explain how the pterosaurs became airborne have led to suggestions that they launched themselves by jumping from cliffs, by dropping from trees, or even by rising into light winds from the crests of waves. Each hypothesis has its difficulties. The first wrongly assumes that the pterosaurs’ hind feet resembled a bat’s and could serve as hooks by which the animal could hang in preparation for flight. The second hypothesis seems unlikely because large pterosaurs could not have landed in trees without damaging their wings. The third calls for high waves to channel updrafts. The wind that made such waves however, might have been too strong for the pterosaurs to control their flight once airborne.
1. It can be inferred from the passage that scientists now generally agree that the (A) enormous wingspan of the pterosaurs enabled them to fly great distances (B) structure of the skeleton of the pterosaurs suggests a close evolutionary relationship to bats (C) fossil remains of the pterosaurs reveal how they solved the problem of powered flight (D) pterosaurs were reptiles (E) pterosaurs walked on all fours
7. It can be inferred from the passage that some scientists believe that pterosaurs (A) lived near large bodies of water (B) had sharp teeth for tearing food (C) were attacked and eaten by larger reptiles (D) had longer tails than many birds (E) consumed twice their weight daily to maintain their body temperature
I had this same passage off GMATTER yesterday.
1: Answer is D. "solved the problems of powered flight, and exactly what these creatures were—reptiles or birds—are among the questions scientists have puzzled over.
Perhaps the least controversial assertion about the pterosaurs is that they were reptiles. Their skulls, pelvises, and hind feet are reptilian."
7: I ran outta time and had to guess on this one. If I had reread the question, the answer would have been obvious.
It can be inferred from the passage that SOME scientists believe that pterosaurs.
At the very end it discusses how these creatures attained flight. One suggestion was wind generated by waves. This suggests that some scientists believe that these animals were near large bodies of water.
Key word here SOME! rghhhh
Also agree w/ everyone here, in the future please post all the questions. (its just by chance that I did this passage yesterday so the passage is still fresh).
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This passage is from RC1000 - Hence forth I will post all questions. It was just too long. I am practicing these because I am weak at RC.
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just did this yesterday, did not agree neither on 7 (answer is A by the way)
I just agreed to disagree and moved on, hundreds more to go...
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ronron wrote: just did this yesterday, did not agree neither on 7 (answer is A by the way)
I just agreed to disagree and moved on, hundreds more to go...
Ya 7 is A.
Forgot to actually post the answer.
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