TF阅读真题第941篇Megapode Approaches to Incubation
Megapode Approaches to Incubation
题目：
The megapodes are a family of birds with unusually large legs. Alone among birds, megapodes do not incubate their eggs (keep eggs warm so that they develop) by direct parental contact. A classic example is the Micronesian scrub fowl, an inhabitant of the western Pacific Rim islands of Palau and the northern Marianas. In common with most megapodes, birds on Palau use their substantial legs to build large mounds out of organic material, which then serve as incubators for their eggs. It is the heat released by microorganisms decomposing plant material that actually provides the heat source for incubation. The function of the rest of the mound, usually sand, is to keep the heat generated by decomposition from leaking out of the mound, and also to provide a material in which an egg can be concealed.
Since megapode eggs hatch without parental support, it is not surprising that a newly hatched megapode emerges in a far more advanced stage of development than any other bird. A typical egg is two or three times larger than the eggs of a bird of similar body size, and also contains far more yolk (yellow, nutritious part of an egg) than equivalent species. The shell is thinner than for other birds, and has specially adapted pores (small openings) that aid gaseous exchange in the egg’s unusual buried state. The result is that a megapode at hatching is something of a super-chick. Rather than politely chipping out of its egg with its egg- tooth, it instead kicks out with its feet. It climbs its way up through the sand and litter, apparently sometimes resting on its back and kicking upward, at the same time allowing its soft, fine feathers to dry. Once at the surface it is so well developed that it can actually fly almost immediately, which is unique among birds. In practice, however, a megapode chick is usually exhausted when it first reaches the surface and is very vulnerable. It is literally unsteady on its feet, however large they might be, for several hours.
The life history of megapodes is unusual enough, but for the Micronesian scrub fowl, there is a further short chapter to tell, which in some ways marks out this species as still more unusual even than its peers. While we might see mound-building as an extreme adaptation to noncontact incubation, it isn’t, in fact, the only one. The Micronesian scrub fowl is a mound-builder on Palau, but on the Marianas Island group it practices something completely different.
The islands of the Pacific Rim are part of the Ring of Fire, a region of the world with heightened surface volcanic activity. On some islands there are geothermal vents- openings on Earth’s surface out of which heated water flows, and the surrounding ground is warmed to a consistent temperature. Although these are naturally limited in scale and space, they do afford opportunities for Micronesian scrub fowl (and other species) to lay their eggs; in these cases the parent doesn’t even need to tend a mound. All a female has to do is dig a pit, lay her egg, and allow the warmth of the ground to do the rest. Elsewhere, some megapodes do something similar, but rather than selecting ground warmed by geothermal activity, they simply lay eggs in the sand and allow the Sun to keep them warm. In at least some areas, it seems that the ever- adaptable Micronesian scrub fowl does this too. If so, it is perhaps the only bird in the world with three separate strategies for incubating its eggs.
But how might mound-building have arisen in the first place, bearing in mind that it involves a profound behavioral switch that no other species of bird has followed? The theory goes that it probably developed from a habit of leaving the eggs temporarily covered by vegetation, for safety reasons, when an adult left the nest. From there the ancestral parents would have begun to spend less and less time with their eggs, as the knack of using heat from decomposition caught on. Finally, ancient megapodes abandoned their chicks completely. Such a change could never, perhaps, have happened on continental landmasses, where such adaptations would probably have made chicks vulnerable to predation by large animals, including other birds. On oceanic islands, however, with no land predators, evolution often favors unusual branches of adaptation.+
1
The megapodes are a family of birds with unusually large legs. Alone among birds, megapodes do not incubate their eggs (keep eggs warm so that they develop) by direct parental contact. A classic example is the Micronesian scrub fowl, an inhabitant of the western Pacific Rim islands of Palau and the northern Marianas. In common with most megapodes, birds on Palau use their substantial legs to build large mounds out of organic material, which then serve as incubators for their eggs. It is the heat released by microorganisms decomposing plant material that actually provides the heat source for incubation. The function of the rest of the mound, usually sand, is to keep the heat generated by decomposition from leaking out of the mound, and also to provide a material in which an egg can be concealed.
The word “concealed”in the passage is closest in meaning to
Vocabulary Questions词汇题
Asurrounded
Bdeveloped
Chidden
Dsupported
2
The megapodes are a family of birds with unusually large legs. Alone among birds, megapodes do not incubate their eggs (keep eggs warm so that they develop) by direct parental contact. A classic example is the Micronesian scrub fowl, an inhabitant of the western Pacific Rim islands of Palau and the northern Marianas. In common with most megapodes, birds on Palau use their substantial legs to build large mounds out of organic material, which then serve as incubators for their eggs. It is the heat released by microorganisms decomposing plant material that actually provides the heat source for incubation. The function of the rest of the mound, usually sand, is to keep the heat generated by decomposition from leaking out of the mound, and also to provide a material in which an egg can be concealed.
According to paragraph 1,which of the following often helps the eggs of the Micronesian scrub fowl to stay warm?
Factual Information Questions事实信息题
AThe parents sit on large mounds to warm their eggs.
BSand prevents heat from escaping the pile that holds the eggs.
CThe parents continuously bring new warm plant material to cover their eggs in mounds.
DMicroorganisms in mounds interact with material in the eggs in a process that releases heat.
3
Since megapode eggs hatch without parental support, it is not surprising that a newly hatched megapode emerges in a far more advanced stage of development than any other bird. A typical egg is two or three times larger than the eggs of a bird of similar body size, and also contains far more yolk (yellow, nutritious part of an egg) than equivalent species. The shell is thinner than for other birds, and has specially adapted pores (small openings) that aid gaseous exchange in the egg’s unusual buried state. The result is that a megapode at hatching is something of a super-chick. Rather than politely chipping out of its egg with its egg- tooth, it instead kicks out with its feet. It climbs its way up through the sand and litter, apparently sometimes resting on its back and kicking upward, at the same time allowing its soft, fine feathers to dry. Once at the surface it is so well developed that it can actually fly almost immediately, which is unique among birds. In practice, however, a megapode chick is usually exhausted when it first reaches the surface and is very vulnerable. It is literally unsteady on its feet, however large they might be, for several hours.
Why does the author describe how a newly hatched megapode“climbs its way up through the sand and litter”?
Rhetorical Purpose Questions修辞目的题
ATo help illustrate the dangers faced by newly hatched birds without parental support
BTo help emphasize the advanced stage of development that newly hatched megapodes are in
CTo help identify a disadvantage of the megapode practice of egg burying
DTo help explain why megapodes kick out of their eggs
4
Since megapode eggs hatch without parental support, it is not surprising that a newly hatched megapode emerges in a far more advanced stage of development than any other bird. A typical egg is two or three times larger than the eggs of a bird of similar body size, and also contains far more yolk (yellow, nutritious part of an egg) than equivalent species. The shell is thinner than for other birds, and has specially adapted pores (small openings) that aid gaseous exchange in the egg’s unusual buried state. The result is that a megapode at hatching is something of a super-chick. Rather than politely chipping out of its egg with its egg- tooth, it instead kicks out with its feet. It climbs its way up through the sand and litter, apparently sometimes resting on its back and kicking upward, at the same time allowing its soft, fine feathers to dry. Once at the surface it is so well developed that it can actually fly almost immediately, which is unique among birds. In practice, however, a megapode chick is usually exhausted when it first reaches the surface and is very vulnerable. It is literally unsteady on its feet, however large they might be, for several hours.
Paragraph 2 suggests that which of the following is true about the flying ability of newly hatched megapodes?
Inference Questions推理题
AThey are not able to fly because their feathers are still soft and wet.
BThe relatively large size of their legs makes it difficult for them to fly.
CAlthough in theory they are able to fly right away, they generally do not for at least several hours.
DFlying causes them to be unsteady on their feet when back on land.
5
The life history of megapodes is unusual enough, but for the Micronesian scrub fowl, there is a further short chapter to tell, which in some ways marks out this species as still more unusual even than its peers. While we might see mound-building as an extreme adaptation to noncontact incubation, it isn’t, in fact, the only one. The Micronesian scrub fowl is a mound-builder on Palau, but on the Marianas Island group it practices something completely different.
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.
Sentence Simplification Questions句子简化题
AThe Micronesian scrub fowl has peers that, in some ways, are even more unusual than the Micronesian scrub fowl itself.
BUnusually enough, the life history of the Micronesian scrub fowl is shorter than the life histories of other megapodes.
CA short chapter about the Micronesian scrub fowl shows that the life history of megapodes is quite unusual.
DThe life history of the Micronesian scrub fowl is even more unusual than that of other megapodes.
6
The islands of the Pacific Rim are part of the Ring of Fire, a region of the world with heightened surface volcanic activity. On some islands there are geothermal vents- openings on Earth’s surface out of which heated water flows, and the surrounding ground is warmed to a consistent temperature. Although these are naturally limited in scale and space, they do afford opportunities for Micronesian scrub fowl (and other species) to lay their eggs; in these cases the parent doesn’t even need to tend a mound. All a female has to do is dig a pit, lay her egg, and allow the warmth of the ground to do the rest. Elsewhere, some megapodes do something similar, but rather than selecting ground warmed by geothermal activity, they simply lay eggs in the sand and allow the Sun to keep them warm. In at least some areas, it seems that the ever- adaptable Micronesian scrub fowl does this too. If so, it is perhaps the only bird in the world with three separate strategies for incubating its eggs.
Paragraph 4 identifies which TWO of the following as incubation strategies used by Micronesian scrub fowl? To receive credit, you must select TWO answer choices.
Factual Information Questions事实信息题
Select 2 answers
AProtecting eggs placed inside a mound until they hatch
BPlacing eggs in a pit filled with heated water
CDigging a hole in geothermally heated ground
DLaying eggs in sand, where they are warmed by sunlight
7
But how might mound-building have arisen in the first place, bearing in mind that it involves a profound behavioral switch that no other species of bird has followed? The theory goes that it probably developed from a habit of leaving the eggs temporarily covered by vegetation, for safety reasons, when an adult left the nest. From there the ancestral parents would have begun to spend less and less time with their eggs, as the knack of using heat from decomposition caught on. Finally, ancient megapodes abandoned their chicks completely. Such a change could never, perhaps, have happened on continental landmasses, where such adaptations would probably have made chicks vulnerable to predation by large animals, including other birds. On oceanic islands, however, with no land predators, evolution often favors unusual branches of adaptation.
The word “temporarily”in the passage is closest in meaning to
Vocabulary Questions词汇题
Acompletely
Bcarefully
Cmore or less
Dfor a limited time
8
But how might mound-building have arisen in the first place, bearing in mind that it involves a profound behavioral switch that no other species of bird has followed? The theory goes that it probably developed from a habit of leaving the eggs temporarily covered by vegetation, for safety reasons, when an adult left the nest. From there the ancestral parents would have begun to spend less and less time with their eggs, as the knack of using heat from decomposition caught on. Finally, ancient megapodes abandoned their chicks completely. Such a change could never, perhaps, have happened on continental landmasses, where such adaptations would probably have made chicks vulnerable to predation by large animals, including other birds. On oceanic islands, however, with no land predators, evolution often favors unusual branches of adaptation.
According to paragraph 5, mound-building likely began with
Factual Information Questions事实信息题
Athe use of decomposing plant material as a heat source
Bthe complete abandonment of young chicks by some megapode parents
Cthe practice of covering eggs with plant material for protection
Dthe habit of laying eggs on top of piles of vegetation
9
The megapodes are a family of birds with unusually large legs. Alone among birds, megapodes do not incubate their eggs (keep eggs warm so that they develop) by direct parental contact. [■] A classic example is the Micronesian scrub fowl, an inhabitant of the western Pacific Rim islands of Palau and the northern Marianas. [■] In common with most megapodes, birds on Palau use their substantial legs to build large mounds out of organic material, which then serve as incubators for their eggs. [■] It is the heat released by microorganisms decomposing plant material that actually provides the heat source for incubation. [■] The function of the rest of the mound, usually sand, is to keep the heat generated by decomposition from leaking out of the mound, and also to provide a material in which an egg can be concealed.
Look at the four squares [■] that indicate where the following sentence could be added to the passage
Instead, the various species within the family use a number of external heat sources.Insert Text Questions句子插入题
Where would the sentence best fit？Click on a square sentence to the passage.
10
Megapodes are the only family of birds that do not sit on their eggs to keep them warm.
Prose Summary Questions概要小结题
Select 3 answers
AMegapode eggs are adapted for enabling megapode chicks to develop quickly while the eggs are buried, which allows them to take care of themselves immediately after hatching.
BAlthough Micronesian scrub fowl living on Palau completely abandon their eggs, those living on the Marianas Island group sometimes return to their mounds to add vegetation.
CIn spite of the fact that megapode eggs have no parents to watch over them, megapodes have a greater chance of successfully hatching than other island bird species.
DMegapodes commonly use mounds of decomposing vegetation to keep their eggs warm, but some, like the Micronesian scrub fowl, vary their strategies depending on where they live.
ENoncontact incubation may have evolved on volcanic islands in the Pacific Rim, where periodic volcanic activity may have forced megapode parents to leave their eggs.
FIsland environments provided the necessary conditions for mound-building to develop gradually as megapodes left their eggs for longer and longer periods of time.
