1．Larger brain size linked to longer life in deerThe size of a female animals'brain may determine whether they live longer and have more healthy offspring （后代），according to new research led by the University of Cambridge．
The study，published in the Royal Society Open Science journal，shows that female red deer with larger brains live longer and have more surviving offspring than those with smaller brains．Brain size is passed down through the generations．This is the first extensive study of individual differences in brain size in wild mammals and draws on data comparing seven generations of deer．
Across species of mammals，brain size varies widely．This is thought to be a consequence of specific differences in the benefits and costs of a larger brain．Mammals with larger brains may，for example，have greater cognitive abilities that enable them to adapt better to environmental changes or they may have longer lifespans （壽命）．But there may also be disadvantages：for instance，larger brains require more energy，so individuals that possess them may show reduced fertility （繁殖力）．
The researchers，based at the University of Cambridge's Zoology Department and Edinburgh University's Institute of Evolutionary Biology，wanted to test if they could find more direct genetic or non-genetic evidence of the costs and benefits of large brain size by comparing the longevity （長(zhǎng)壽） and survival of individuals of the same species with different sized brains．Using the skulls of 1，314wild red deer whose life histories and breeding success had been monitored in the course of a long-term study on the Isle of Rum，they found that females with larger endocranial volumes （腦腔容量） lived longer and produced more surviving offspring in the course of their lives．
Lead author Dr Corina Logan，a Gates Cambridge Scholar，says，"The reasons for the association between brain size and longevity are not known，but other studies have suggested that larger brains are a consequence of the longer-lived species having longer developmental periods in which the brain can grow．These hypotheses （假設(shè)） were generated from cross-species correlations； however，testing such hypotheses requires investigations at the within-species level，which is what we did．"
Dr Logan adds，"We found that some of the cross-species predictions about brain size held for female red deer，and that none of the predictions were supported in male red deer．This indicates that each sex likely experiences its own set of trade-offs （權(quán)衡，協(xié)調(diào)） with regard to brain size．"The study also showed that females'relative endocranial volume is smaller than that of males，despite evidence of selection for larger brains in females．
Professor Tim Clutton-Brock，who set up the Rum Red Deer study with Fiona Guinness in 1972and initiated the work on brain size，points out，"The reason that this kind of study has not been conducted before is that it requires long term records of a large number of individuals across multiple generations and data of this kind are still rare in wild animals．"
1．What does the new research about brain size reveal？C
A．Large-brain red deer tend to be more reproductive．
B．Large-brain female deer survive small-brain male deer．
C．Brain size causes individual differences in some mammals．
D．Brain size has been increasing from generation to generation．
2．For different species of mammals，brain size varies widely in thatB．
A．mammals can develop different adaptive abilities
B．a(chǎn) larger brain has its advantages and disadvantages
C．different mammals are born with different lifespans
D．brain size is affected by genetic or non-genetic factors
3．What can we learn about the relation between brain size and longevity？A
A．The cause and effect needs to be further investigated．
B．Brain size absolutely determines animals'longevity．
C．Longer-lived species allow brains to grow to a large size．
D．The cross-species assumptions apply to red deer of both sexes．
4．What can we infer from Professor Tim Clutton-Brock's words？D
A．Researchers can't possibly reach a conclusion about the reason．
B．Researchers are not patient enough to keep long term records．
C．Such research has been thoroughly conducted on wild animals before．
D．Such research will witness great difficulty in the long-term process．
分析 本文屬于說明文閱讀，作者通過這篇文章主要向我們描述了大腦的大小導(dǎo)致某些哺乳動(dòng)物的個(gè)體差異和壽命的長(zhǎng)短．
解答 1．C．細(xì)節(jié)理解題．根據(jù)第一段Larger brain size linked to longer life in deerThe size of a female animals'brain may determine whether they live longer and have more healthy offspring （后代），according to new research led by the University of Cambridge可知關(guān)于大腦大小的最新研究揭示了大腦的大小導(dǎo)致某些哺乳動(dòng)物的個(gè)體差異；故選C．
2．B．細(xì)節(jié)理解題．根據(jù)第三段Mammals with larger brains may，for example，have greater cognitive abilities that enable them to adapt better to environmental changes or they may have longer lifespans （壽命）．But there may also be disadvantages：for instance，larger brains require more energy可知較大的大腦有優(yōu)點(diǎn)也有缺點(diǎn)；故選B．
3．A．細(xì)節(jié)理解題．根據(jù)文章，"The reasons for the association between brain size and longevity are not known，but other studies have suggested that larger brains are a consequence of the longer-lived species having longer developmental periods in which the brain can grow可知關(guān)于大腦大小和壽命之間的關(guān)系其原因和后果需要進(jìn)一步調(diào)查；故選A．
4．D．推理判斷題．根據(jù)最后一段The reason that this kind of study has not been conducted before is that it requires long term records of a large number of individuals across multiple generations and data of this kind are still rare in wild animals可知這些研究將在未來長(zhǎng)期過程中遇到很大困難；故選D
點(diǎn)評(píng) 考察學(xué)生的細(xì)節(jié)理解和推理判斷能力，做細(xì)節(jié)理解題時(shí)一定要找到文章中的原句，和題干進(jìn)行比較，再做出正確的選擇．在做推理判斷題不要以個(gè)人的主觀想象代替文章的事實(shí)，要根據(jù)文章事實(shí)進(jìn)行合乎邏輯的推理判斷．
）劃掉．