1〉Spring is the season for flashy mates, at least for finches. It is only later in the year that the females choose based on genetic diversity,
According to new research from two scientists at the University of Arizona., Their 10-year study of a colony of 12,000 finches in Montana has revealed the seasonal dynamics of finch attraction and thereby resolved an evolutionary conundrum.
2〉Previous research had shown that female birds go for the most resplendent mates; in the case of finches, this means the males with the reddest breast. Some scientists argue that such sexual selection is the driving force behind apparently useless displays, such as red breasts or the brilliance of a male peacock's tail. "For such elaborate traits to evolve, you have to have mating patterns where everyone wants the same thing," ecologist Kevin Oh explains.
3> On the other hand, in a relatively stable population, if all females mated with the flashiest guy, the charm of finches would become inbred. Instead, female finches should seek out males with the most genetic difference from themselves. But this would lead to a variety of hues for male finch breasts. "Even though preference for genetically complementary mates is widely documented, it has always puzzled people that individual differences in mate preference do not prevent the evolution of elaborate ornaments," ecologist Alexander Badyaev notes.
4> Badyaev has spent the last 10 years photographing, taking DNA samples and measuring a charm of house finches in Montana. By 2004, he had the intimate details of the entire population, including who was mating with whom, who was cheating on whom, and whose genes got passed on to the next generation. He also has pictures of the relative rosiness of any given male finches breast. "We have 10 sequential generations of wild birds completely genotyped," he says. "It's never been done before."
5> By analyzing that record, the researchers found that early in the mating season, females chose the male finch with the reddest breast. But as the season wore on--and new females entered the charm--they typically chose males with strong genetic differences from themselves. And those tempted to stray typically chose a mate more genetically different than their regular partner, according to the research presented in Proceedings of the Royal Society B.
6> Although it remains unclear how finches sense genetic difference, the finding does reveal a new strategy for evolving elaborate ornamentation while preventing inbreeding. And that means this behavior might apply to more than just one charm of finches in Montana.
3>段再引入一个与2段中观点相悖的观点.然后利用4和5段中的事实论证该观点.注意：on the other hand。
6.>总结全文,
呵，觉得这结构挺经典的，真题还没敢研究，不太了解出题思路。但是比如在第一段的第二句中，作者既然应用强调句型it is……that, 那么是否有可能这样考：choose based on genetic diversity是在什么时间A。spring. B.later in the year（B选项意思太容易理解，出题人也许可以改改），总之既然是强调句，那么必是作者表达的重点。一段最后一句：conundrum=riddle=problem是否也会考个语意题目？作者: 小叮铛 时间: 2006-6-27 11:03
1〉 Spring is the season for flashy mates, at least for finches. It is only later in the year that the females choose based on genetic diversity, according to new research from two scientists at the University of Arizona. Their 10-year study of a colony of 12,000 finches in Montana has revealed the seasonal dynamics of finch attraction and thereby resolved an evolutionary conundrum.
词汇:
flashy adj浮华, 一组相关词汇2〉段中resplendent adj. brilliance. n. 3)段中elaborate ornaments精雕细琢的装饰
词组及固定搭配:
based on 基于…
genetic diversity .基因的多样性
seasonal dynamics 季节性的变动
resolve a conundrum=riddle=problem 解决一个难题。
句型:
It is only later in the year that….. 强调句(作者在此强调时间,这类句型可能是考查的重点.可以想象,既然作者强调某部分的信息,那么该部分在全文应该有重要地位,可以想个问题:在春天的时候,雀类根据什么选择交配伙伴?在比较靠近年底的时候,又是如何选择?)在作文中,如果自己想强调某部分的内容,也许该句型能效劳.
Previous research had shown that female birds go for the most resplendent mates; in the case of finches, this means the
males with the reddest breast. Some scientists argue that such sexual selection is the driving force behind apparently useless displays, such as red breasts or the brilliance of a male peacock's tail. "For such elaborate traits to evolve, you have to have mating patterns where everyone wants the same thing," ecologist Kevin Oh explains.
词组及固定搭配:
go for 追寻 in the case of 在…例子中.注意与in case 的区别.
sexual selection 性选择. driving force驱动力
mating patterns 交配模式
句型:
Previous research had shown that…;in the case of….这类”无灵句” 句型,往往表达客观的事实.这在作文中,也可以套用,尤其是图表类.如,the chart reveals/shows that ….;in the case of +整体中某个具体部分+其他成分.
On the other hand, in a relatively stable population, if all females mated with the flashiest guy, the charm of finches would become inbred. Instead, female finches should seek out males with the most genetic difference from themselves. But this would lead to a variety of hues for male finch breasts. "Even though preference for genetically complementary mates is widely documented, it has always puzzled people that individual differences in mate preference do not prevent the evolution of elaborate ornaments," ecologist Alexander Badyaev notes.
词汇:
Difference 这类名词有与之对应的形容词 different.这类名词与后面介词的搭配往往和形容词一样.既: difference from, different from.
后面句子中的preference也可以这样搭配.即preference to .(丁SIR好象在第7期文摘精读中,更为详细地讲了该词.可以参考)
还有诸如.association(associate) with Priority(prior) to , .等.
