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[机经题库答案] 托福阅读生物类真题Dinosaurs and Parental Care原文+题目汇总

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发表于 2017-5-15 14:30 |显示全部楼层
类别:生物类
真题150201CN-P3
Title:Dinosaurs and Parental Care
From  fossil evidence alone the question of whether or not dinosaurs cared for their young is very difficult to answer.  Because behaviors are not preserved in the fossil  record, we can only make inferences from  indirect evidence. Parental care can be divided into  two types of behavior: prehatching (building nests and  incubating eggs—for example, sitting on top of them  so as to warm  the eggs and encourage hatching) and posthatching (feeding the young and guarding the nests). Most of our evidence comes  from alleged dinosaur rookeries (places where  nests are built). Several have been excavated in eastern Montana, where a  large concentration of dinosaur  nests was found at a place now called Egg Mountain. Most  of these probably belonged to the hadrosaur Maiasaura. Preserved in these nests are the bones of baby  dinosaurs. The finds at Egg Mountain  and other sites  around the world  document that dinosaurs laid their eggs in nests.  
The nests at Egg Mountain are  reported to be equally spaced, separated by a space corresponding to the length of an adult Maiasaura. From this arrangement  scientists have inferred that the nests were separated in  this way to allow incubation in a  tightly packed nesting colony. Although this interpretation is  open to challenge, the discovery of Oviraplor  adults on top of Oviraplor  egg clutches (as determined by embryos in some eggs), is relatively powerful evidence that at least  these dinosaurs incubated their nests.  
Evidence  for parental care following  hatching is much more controversial. Behavioral speculation based  on indirect fossil evidence is dangerous because the data is not always as  unambiguous as might appear. At  Egg Mountain, many nests contain baby dinosaur bones. Not all the  dinosaurs in the nest are the same  size. Many of the small bones found in the nests are associated with jaws and teeth, teeth that show signs of  wear. It seems reasonable to  assume that the wear was caused by the chewing  of the coarse  plants that were  the hatchlings’ diet.  Because the young were still in the nest, this  food may have  been brought to the rookery  by foraging adults. This line of reasoning suggests that these animals  had an advanced system of parental  care. A closer look at the evidence clouds this interpretation. Analysis of dinosaur embryos indicates that  worn surfaces are present  on the teeth of juveniles even before hatching. Just as a human baby moves inside  the mother before birth,  modern-day archosaurs also grind their teeth before birth, wearing the surface in some spots.  Thus, the fossil  evidence for an  advanced parental care system in extinct dinosaurs is suggestive  but inconclusive, and it is hard even to imagine the sort of paleontologic discovery that could  settle this debate  for good.
The strongest evidence that  extinct dinosaurs had  some form of advanced parental care system is  based on an understanding of the phylogenetic relationships among dinosaurs  and their closest living relatives. Living  dinosaurs (birds), even primitive ones such as ostriches and kiwis, exhibit  parental care, so some form of parental care can be inferred to have existed  in the last common ancestor of all birds. Although  unappreciated, crocodiles are reptiles that are also caring parents. They build nests, guard  the nests, and in some cases dig their young out of the nest when they hear  the chirping young ones hatching. The young even communicate with each other  while still in the egg by  high-frequency squeaks (as birds do). Some evidence suggests that this  squeaking is  a cue for  the synchronization of the hatching. Since birds and crocodiles share a  common ancestor, the simplest explanation for the characteristics they share  (such as nest building and some form of parental care) is that they evolved  only once—that these attributes were present in their common ancestor and  passed on to its descendants. Because extinct dinosaurs also descended from  that ancestor, the simplest and most general theory is that extinct dinosaurs  also shared these characteristics, even though they cannot be directly  observed, and we cannot be sure how elaborate their parental care was.
Paragraph 1  
From  fossil evidence alone the question of whether or not dinosaurs cared for their young is very difficult to answer.  Because behaviors are not preserved in the fossil  record, we can only make inferences from  indirect evidence. Parental care can be divided into  two types of behavior: prehatching (building nests and  incubating eggs—for example, sitting on top of them  so as to warm  the eggs and encourage hatching) and posthatching (feeding the young and guarding the nests). Most of our  evidence comes from  alleged dinosaur rookeries (places where nests are built).  Several have been excavated in  eastern Montana, where a large concentration of dinosaur nests was found  at a place now called  Egg Mountain. Most  of these probably belonged to the hadrosaur Maiasaura. Preserved in these nests are the bones of baby  dinosaurs. The finds at Egg Mountain  and other sites  around the world  document that dinosaurs laid their eggs in nests.
    
1.        The  word “alleged” in the passage is  closet in meaning to  
¡  scattered  
¡  supposed  
¡  isolated  
¡  exposed  
  
2.        Paragraph  1 answers which  of the following questions about parental care in dinosaurs?  
¡  Which  type of parental care was more important for  the survival of dinosaur young, prehatching care or posthatching care?  
¡  Why were  dinosaur remains in eastern Montana  preserved rather than  destroyed over time?  
¡  Did Maiasaura hadrosaurs provide types  of parental care not provided by other dinosaurs?  
¡  What  evidence supports the view that Maiasaura females laid their eggs in nests?  
  
Paragraph 1  
From  fossil evidence alone the question of whether or not dinosaurs cared for their young is very difficult to answer.  Because behaviors are not preserved in the fossil  record, we can only make inferences from  indirect evidence. Parental care can be divided into  two types of behavior: prehatching (building nests and  incubating eggs—for example, sitting on top of them  so as to warm  the eggs and encourage hatching) and posthatching (feeding the young and guarding the nests). Most of our evidence comes  from alleged dinosaur rookeries (places where  nests are built). Several have been excavated in eastern Montana, where a  large concentration of dinosaur  nests was found at a place now called Egg Mountain. Most  of these probably belonged to the hadrosaur Maiasaura. Preserved in these nests are the bones of baby  dinosaurs. The finds at Egg Mountain  and other sites  around the world  document that dinosaurs laid their eggs in nests.  
  
Paragraph 2  
The nests at Egg Mountain are  reported to be equally spaced, separated by a space corresponding to the length of an adult Maiasaura. From this arrangement  scientists have inferred that the nests were separated in  this way to allow incubation in a  tightly packed nesting colony. Although this interpretation is  open to challenge, the discovery of Oviraplor  adults on top of Oviraplor  egg clutches (as determined by embryos in some eggs), is relatively powerful evidence that at least  these dinosaurs incubated their nests.  
  
3.        According to paragraphs 1 and 2, the fossil  record most clearly shows that dinosaurs engaged in which of  the following behaviors?  
¡  Laying  eggs in nests  
¡  Hiding eggs  
¡  Feeding young  
¡  Storing food  
  
4.        According  to paragraph 2, which of the following supports the theory  that the Maiasaura  incubated their eggs?  
¡  The  examination of embryos found in some eggs  
¡  The  large concentration of nests in one location  
¡  The  amount of space between nests  
¡  The  discovery of adult Maiasaura bones on top of egg clutches
  
Paragraph 3  
Evidence  for parental care following  hatching is much more controversial.  Behavioral speculation based on indirect fossil evidence is  dangerous because the data is not always as unambiguous as might appear. At Egg  Mountain, many nests contain baby dinosaur bones. Not all the dinosaurs in the nest are the same size. Many of  the small bones found in the nests are associated with jaws and teeth, teeth that show signs of wear. It seems reasonable to assume that  the wear was caused by the chewing  of the coarse  plants that were  the hatchlings’ diet.  Because the young were still in the nest, this  food may have  been brought to the rookery  by foraging adults. This line of reasoning suggests that these animals  had an advanced system of parental  care. A closer look at the evidence clouds this interpretation. Analysis of dinosaur embryos indicates that  worn surfaces are present  on the teeth of juveniles even before hatching. Just as a human baby moves inside  the mother before birth,  modern-day archosaurs also grind their teeth before birth, wearing the surface in some spots.  Thus, the fossil  evidence for an  advanced parental care system in extinct dinosaurs is  suggestive but inconclusive, and it  is hard even to imagine the sort of paleontologic discovery that could settle  this debate for  good.  
  
5.        The  word “controversial” in the passage  is closet in meaning to
¡   limited  
¡   convincing  
¡   relevant  
¡   debatable  
  
6.        The  word “inconclusive” in the passage is  closet in meaning to  
¡   not decisive  
¡   insignificant
¡   not valid  
¡   misleading
    
7.        According to paragraph 3, the patterns of wear found on the teeth of young dinosaurs may indicate which of  the following?
¡  Baby  dinosaurs were eating food brought to them by their parents.  
¡   Early  development of jaw and teeth varied according to a dinosaur’s size.  
¡   Dinosaurs went foraging for food at an early age.
¡   Baby dinosaurs did not begin to eat solid  food until after they left the nest.
    
8.        In paragraph 3, why does  the author mention that baby archosaurs ground their teeth inside the egg?  
¡  To support the claim that baby dinosaurs in the egg shared certain  behaviors with human babies before birth  
¡  To contrast the behavior of bay archosaurs with  that of other types of dinosaurs  
¡   To cast  doubt on the claim that adult dinosaurs fed their hatchlings in the nest  
¡   To explain why the  teeth of baby  archosaurs were more  worn than those  of other juveniles
    
Paragraph 4
The strongest evidence that extinct  dinosaurs had some  form of advanced parental care system is based on an understanding of  the phylogenetic relationships among dinosaurs and their closest living relatives. Living  dinosaurs (birds), even primitive ones such as ostriches and kiwis, exhibit  parental care, so some form of parental care can be inferred to have  existed in the last common ancestor of all birds. Although  unappreciated, crocodiles are reptiles that are also caring parents. They build nests, guard the nests,  and in some cases dig their young out of the nest when they hear  the chirping young ones hatching. The young even communicate with each other  while still in the egg by  high-frequency squeaks (as birds do). Some evidence suggests that this  squeaking is a cue for the synchronization of the hatching.  Since birds and crocodiles share a common ancestor, the simplest explanation for the characteristics they share (such  as nest building and some form of parental care) is that they  evolved only once—that these attributes were  present in their common ancestor and passed on to its  descendants. Because extinct dinosaurs also descended from that  ancestor, the simplest and most general  theory is that extinct dinosaurs also shared these characteristics, even though they cannot be directly observed, and we cannot  be sure how  elaborate their parental care  was.  
  
9.       Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.  
¡  The  simplest explanation for the similarities between birds and crocodiles is  that they evolved at the same time.
¡   A common ancestor is probably the source of  the shared traits of crocodiles and birds.  
¡  The  originally similar traits of birds and crocodiles increased after evolving  through a shared ancestor.  
¡  Only one shared  pattern of behavior—that of nest building—was present in the common ancestor of birds and crocodiles.  
  
10.    The  word “elaborate” in the passage is  closet in meaning to  
¡   widespread  
¡   reliable  
¡   well developed  
¡   long lasting  
  
11.    Paragraph 4 answers all of the following  questions about crocodiles EXCEPT:  
¡   What is the evidence that crocodiles are  caring parents?  
¡   Why do crocodile parents communicate with the  young inside their eggs?  
¡  What is a possible  reason for the high-frequency sounds that crocodiles make inside their eggs?  
¡  How do  crocodiles participate in the hatching process of their young?  
  
12.    In paragraph 4, the author discusses birds  and crocodiles in order to  
¡   contrast patterns of parenting behavior in  both living and extinct animals  
¡   provide evidence that sophisticated parental care behaviors evolved  only relatively recently  
¡  demonstrate that  parental care behaviors have continued to evolve since  the time of the  dinosaurs  
¡  support the theory that  extinct dinosaurs probably inherited some kind of parental care system  
  
Paragraph 1  
From  fossil evidence alone the question of whether or not dinosaurs cared for their young is very difficult  to answer. ■Because behaviors are  not preserved in the fossil record, we can only make inferences from  indirect evidence. ■Parental care can be divided into  two types of behavior: prehatching (building nests and  incubating eggs—for example, sitting on top of them  so as to warm  the eggs and encourage hatching) and posthatching (feeding the young and guarding the nests).  ■Most of our evidence comes from alleged  dinosaur rookeries (places where nests are built). ■Several have been  excavated in eastern Montana, where a large concentration of dinosaur nests  was found at a place now called Egg Mountain. Most of these probably belonged  to the hadrosaur Maiasaura.  Preserved in these nests are the bones of baby dinosaurs. The finds at Egg  Mountain and other sites around the world document that dinosaurs laid their  eggs in nests.  
  
13.    Look at the four squares [■] that indicate where the following sentence  can be added to the passage.
  Evidence of the former  is easier to find than  that of the latter.  
Where would  the sentence best fit? Click  on a square [■] to add the sentence to the passage.  
  
14.   Directions: An introductory sentence for a brief summary  of the passage is provided  below. Complete the summary  by selecting the THREE answer choices that express the most important ideas  in the passage. Some answer choices do not belong in the summary because they express ideas that are not presented in the passage  or are minor ideas in the passage. This question is worth 2 points.
  
Drag your  choices to the spaces where  they belong. To review  the passage, click  on View Text.
   
         
Scientists  must  use  indirect  evidence       to  determine       whether  extinct       dinosaurs  cared  for  their      young.      
     
     
          
     
Answer Choices    
¡  Because baby dinosaur bones and  eggs were very delicate, there are relatively few preserved as fossils, so little is known about  dinosaur young.  
¡  Fossils from sites like Egg  Mountain indicate that dinosaurs built nests, and perhaps that they  incubated their eggs and fed their hatchlings.  
¡  Fossil evidence such as the  spacing of nests may indicate  advanced parental care but can have different interpretations.  
¡  Tightly packed Oviraplor rookeries indicate that dinosaurs may have tended  to nest in large colonies in order  to better protect both eggs and hatchlings.  
¡  Discovery of hadrosaur bones of different sizes in the same nest  may indicate that,  in some species, older siblings took care of younger ones.  
¡  The  strongest evidence comes from extinct  dinosaurs’ nearest living relatives, birds and  crocodiles, who do engage in many forms of parental care.  
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