物种进化速度能否超过气候变化?
文章来源:未知 文章作者:enread 发布时间:2011-06-09 03:20 字体: [ ]  进入论坛
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Animals and plants may not be able to evolve their way out of the threat posed by climate change, according to a UC Davis study of a tiny seashore animal. The work was published today (June 8) in the journal Proceedings1 of the Royal Society B. The tide pool copepod Tigriopus californicus is found from Alaska to Baja California — but in a unique lab study, the animals showed little ability to evolve heat tolerance2.

"This is a question a lot of scientists have been talking about," said study co-author Eric Sanford, an associate professor of evolution and ecology at UC Davis and a researcher at the university's Bodega Marine3 Laboratory. "Do organisms have the ability to adapt to climate change on a timescale of decades?"

UC Davis graduate student Morgan Kelly, the first author of the paper, collected copepods from eight locations between Oregon and Baja California in Mexico. The tiny shrimplike animals, about a millimeter long, live in tide pools on rocky outcrops(露头) high in the splash zone.

Kelly grew the short-lived copepods in the lab for 10 generations, subjecting them to increased heat stress to select for more heat-tolerant animals.

At the outset, copepods from different locations showed wide variability in heat tolerance. But within those populations, Kelly was able to coax4 only about a half-degree Celsius5 (about one degree Fahrenheit) of increased heat tolerance over 10 generations. And in most groups, the increase in heat tolerance had hit a plateau before that point.

In the wild, these copepods can withstand(抵挡,反抗) a temperature swing of 20 degrees Celsius a day, Kelly said. But they may be living at the edge of their tolerance, she said.

Although the copepods are widespread geographically6, individual populations are very isolated7, confined to a single rocky outcrop where wave splash can carry them between pools. That means there is very little flow of new genes8 across the population as a whole.

"It's been assumed that widespread species have a lot of genetic9 capacity to work with, but this study shows that may not be so," said co-author Rick Grosberg, professor of evolution and ecology at UC Davis. Many other species of animals, birds and plants face stress from climate change, and their habitats have also been fragmented(分裂) by human activity -- perhaps more than we realize, he said.

"The critical point is that many organisms are already at their environmental limits, and natural selection won't necessarily rescue them," Grosberg said.



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1 proceedings Wk2zvX     
n.进程,过程,议程;诉讼(程序);公报
参考例句:
  • He was released on bail pending committal proceedings. 他交保获释正在候审。
  • to initiate legal proceedings against sb 对某人提起诉讼
2 tolerance Lnswz     
n.宽容;容忍,忍受;耐药力;公差
参考例句:
  • Tolerance is one of his strengths.宽容是他的一个优点。
  • Human beings have limited tolerance of noise.人类对噪音的忍耐力有限。
3 marine 77Izo     
adj.海的;海生的;航海的;海事的;n.水兵
参考例句:
  • Marine creatures are those which live in the sea. 海洋生物是生存在海里的生物。
  • When the war broke out,he volunteered for the Marine Corps.战争爆发时,他自愿参加了海军陆战队。
4 coax Fqmz5     
v.哄诱,劝诱,用诱哄得到,诱取
参考例句:
  • I had to coax the information out of him.我得用好话套出他掌握的情况。
  • He tried to coax the secret from me.他试图哄骗我说出秘方。
5 Celsius AXRzl     
adj.摄氏温度计的,摄氏的
参考例句:
  • The temperature tonight will fall to seven degrees Celsius.今晚气温将下降到七摄氏度。
  • The maximum temperature in July may be 36 degrees Celsius.七月份最高温度可能达到36摄氏度。
6 geographically mg6xa     
adv.地理学上,在地理上,地理方面
参考例句:
  • Geographically, the UK is on the periphery of Europe. 从地理位置上讲,英国处于欧洲边缘。 来自辞典例句
  • All these events, however geographically remote, urgently affected Western financial centers. 所有这些事件,无论发生在地理上如何遥远的地方,都对西方金融中心产生紧迫的影响。 来自名作英译部分
7 isolated bqmzTd     
adj.与世隔绝的
参考例句:
  • His bad behaviour was just an isolated incident. 他的不良行为只是个别事件。
  • Patients with the disease should be isolated. 这种病的患者应予以隔离。
8 genes 01914f8eac35d7e14afa065217edd8c0     
n.基因( gene的名词复数 )
参考例句:
  • You have good genes from your parents, so you should live a long time. 你从父母那儿获得优良的基因,所以能够活得很长。 来自《简明英汉词典》
  • Differences will help to reveal the functions of the genes. 它们间的差异将会帮助我们揭开基因多种功能。 来自英汉非文学 - 生命科学 - 生物技术的世纪
9 genetic PgIxp     
adj.遗传的,遗传学的
参考例句:
  • It's very difficult to treat genetic diseases.遗传性疾病治疗起来很困难。
  • Each daughter cell can receive a full complement of the genetic information.每个子细胞可以收到遗传信息的一个完全补偿物。
TAG标签: animals evolution climate
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