专四
Scientists have determined that Archaeopteryx, the earliest known bird, was definitely birdbrained, meaning no disrespect. Indeed, they consider the fossil's brain size decisive evidence that Archaeopteryx had what it took to fly.
The new research suggests, moreover, that birds probably started flying millions of years earlier than scientists previously thought. It is just that fossils of those fast flying birds-predecessors of Archaeopteryx-have never been found.
The researchers, at the Natural History Museum in London, based their findings on the first X-ray examination and reconstruction of the braincase and inner ear of a 147-million-year-old Archaeopteryx specimen. They found that in size, shape and volume, its brain was similar to that of the modem eagle or sparrow.
Measurements of the semicircular canals, the mechanism for balance inside the ear, showed that Archaeopteryx had the “neurological and structural adaptations necessary for flight," the scientists concluded.
Their research, involving an X-ray computed tomography scan, or C.T., of the fossil's braincase and inner ear, is described today in the journal Nature.
Previous studies of the feathered wing and tail of Archaeopteryx and its birdlike anatomy, including a pronounced wishbone, supported the prevailing view of experts that it was capable of some degree of powered flight. Archaeopteryx is considered a prime transitional species in the evolution of some reptiles, probably dinosaurs, into today's birds.
But the research team, led by Dr. Angela Milner, a paleontologist at the British museum, wrote that until their investigation of Archaeopteryx, "little was understood about the extent to which its brain and special senses were adapted for flight."
Dr. Milner said the new study not only established that Archaeopteryx was capable of "controlling the complex business of flying," but also showed "how much there is still to discover about when and how bird flight began."
In a statement issued by the museum, Dr. Milner said, "If flight was this advanced by the time Archaeopteryx was around, then were birds actually flying millions of years earlier than we'd previously thought?"What is the original meaning of "birdbrained" and what does it mean here in the first paragraph?
A．Naive; intelligen
B．Simple-minded; volan
C．Narrow-minded; navigationa
D．Stupid; adapted for fligh
【解析】词汇题。birdbrained原指“愚蠢的”意思，但在本文中却是指具有适应飞行的能力。第1段最后一句表明始祖鸟拥有使其飞翔的东西，结合第4段“科学家总结，耳内控制平衡的半规管的测量显示始祖鸟拥有为了飞翔所必需的神经的和结构的相应改造”，我们可以得知．选项D为正确答案。
【点睛】选项A．“天真的；聪明的”：B．“头脑简单的；会飞的”：C．“小心眼的；航行的“，均不符题意。
你可能感兴趣的试题
A．fossils of those earliest birds haven't been discovered ye
B．the wishbone they studied is just so-called wishbone:
C．there was no study of the role of its brain and some faculties in fligh
D．Archaeopteryx is regarded as the earliest known bir
A．Archaeopteryx can perform very intricate flyin
B．Archaeopteryx is unlikely to be a prime transitional species between reptiles and bird
C．fossils of those first flying birds are bound to be excavated soo
D．a further investigation should be implemented in Archaeopteryx's anatom
A．bod
B．fossi
C．analysi
D．skeleto
最新试题
Write on ANSWER SHEET THREE a note of about 50-60 words base
In some countries young people are encouraged to work or tra
What does the author suggest as the primary factor of formi
What would the author benefit from the habit?
The author would read the words aloud _________．
What was the first new habit that the author would accompli
根据以下资料，回答题：
Dried foods
Nowadays vegetables are most commonly dried
Alkaline solutions are used to